Isolation, selection, and characterization of lactic acid bacteria for a competitive exclusion product to reduce shedding of Escherichia coli O157:H7 in cattle

Lactic acid bacteria (LAB) were selected on the basis of characteristics indicating that they would be good candidates for a competitive exclusion product (CEP) that would inhibit Escherichia coli O157:H7 in the intestinal tract of live cattle. Fecal samples from cattle that were culture negative for E. coli O157:H7 were collected. LAB were isolated from cattle feces by repeated plating on deMan Rogosa Sharpe agar and lactobacillus selection agar. Six hundred eighty-six pure colonies were isolated, and an agar spot test was used to test each isolate for its inhibition of a four-strain mixture of E. coli O157:H7. Three hundred fifty-five isolates (52%) showed significant inhibition. Seventy-five isolates showing maximum inhibition were screened for acid and bile tolerance. Most isolates were tolerant of acid at pH levels of 2, 4, 5, and 7 and at bile levels of 0.05, 0.15, and 0.3% (oxgall) and were subsequently identified with the API system. Lactobacillus acidophilus, Lactobacillus fermentum, Lactobacillus delbreukii, Lactobacillus salivarius, Lactobacillus brevis, Lactobacillus cellobiosus, Leuconostoc spp., and Pediococcus acidilactici were the most commonly identified LAB. Nineteen strains were further tested for antibiotic resistance and inhibition of E. coli O157:H7 in manure and rumen fluid. Four of these 19 strains showed susceptibility to all of the antibiotics, 13 significantly reduced E. coli counts in manure, and 15 significantly reduced E. coli counts in rumen fluid (P < 0.05) during at least one of the sampling periods. One of the strains, M35, was selected as the best candidate for a CEP. A 16S rRNA sequence analysis of M35 revealed its close homology to Lactobacillus crispatus. The CEP developed will be used in cattle-feeding trials.

Coexistent IgG2 and IgA deficiencies in blood donors

BACKGROUND

To meet the transfusion requirements of IgA-deficient patients with anti-IgA, blood services screen random donors to identify potential donors of IgA-deficient blood components. New information reveals that some IgA-deficient persons may also be deficient in IgG2 and may be at increased risk for bacterial infections.

STUDY DESIGN AND METHODS

Serum samples from IgA-deficient blood donors and patients were tested for IgG2 concentration by radial immunodiffusion using monospecific anti-IgG2.

RESULTS

Four (9.0%) of 44 IgA-deficient blood donors and 14 (31.5%) of 44 IgA-deficient patients had coexistent IgG2 and IgA deficiencies. Follow-up interviews with the 4 donors who had coexistent IgG2 and IgA deficiencies revealed that 3 had recurrent respiratory infections and had been hospitalized at least once for pneumonia. The fourth donor did not report a history suggestive of recurrent infections.

CONCLUSION

Some blood donors, recruited specifically because they are IgA deficient, may also be deficient in IgG2. Persons identified by donor screening programs as being IgA deficient should be tested for IgG2. If deficient in IgG2, they should be evaluated for a history of recurrent bacterial infections and counseled accordingly.

Niruriside, a new HIV REV/RRE binding inhibitor from Phyllanthus niruri

During the screening of natural products for their ability to inhibit the binding of HIV-REV protein to [33P]-labeled RRE RNA, one novel compound, niruriside (1), was isolated from the MeOH extract of the dried leaf of Phyllanthus niruri L. by bioassay-guided fractionation. The structure of niruriside was determined by spectroscopic methods. Niruriside showed specific inhibitory activity against the binding of REV protein to RRE RNA with an IC50 value of 3.3 microM; however, niruriside did not protect CEM-SS cells from acute HIV infection at concentrations up to 260 microM using an XTT dye reduction assay.

Genotypic and phenotypic analysis of human immunodeficiency virus type 1 isolates from patients on prolonged stavudine therapy

Development of stavudine resistance was studied using human immunodeficiency virus type 1 isolates from 13 patients treated with stavudine for 18-22 months. Drug sensitivity testing on 11 of these pre- and posttherapy isolates identified only 2 posttreatment isolates with decreased stavudine sensitivity (ED50s < 4-fold higher than the average pretreatment ED50). Genotypic analysis of all 13 pairs of isolates identified multiple mutations in the reverse transcriptase (RT) gene. However, no genetic basis was identified to account for the observed changes in stavudine susceptibility. A recombinant virus containing the entire RT gene of the posttherapy isolate displaying the greatest resistance remained sensitive to stavudine. Five of the stavudine posttreatment isolates developed resistance (9- to 176-fold) to zidovudine, although the relationship between stavudine treatment and the appearance of zidovudine resistance remains unexplained. Analysis of 10 additional pairs of isolates did not confirm this relationship. The low frequency and modest degree of change in stavudine sensitivity following prolonged treatment is very encouraging.

Characterization of a Mutant HIV-1 Reverse Transcriptase Resistant to (+)-(5S)-4,5,6,7-tetrahydro-5-methyl-6-(3-methyl-2-butenyl)-imidazo[4,5,1-jk][1,4]benzodiazepin-2(1H)-thione (TIBO R82150)

A virus strain resistant to R82150, a non-nucleoside reverse transcriptase (NNRT) inhibitor (tetrahydro-imidazo [4,5, 1- jk] [1,4] benzodiazepine-2(1 H)-thione), was isolated following serial passage of HIV-1 RF in CEM-SS cells. The virus is cross-resistant to another non-nucleoside reverse transcriptase inhibitor, TGG-II-23A [1,4-dimethyl-1-[5,5-dimethyl-2-oxazoionyl]-naphthalen-2-one), but remains susceptible to AZT, DDI, D4T and phosphonoformate (PFA). DNA sequencing of reverse transcriptase genes from resistant virus indicated that R82150 selects for amino acid alterations Y181C and V108I. In vitro mutagenized reverse transcriptase and recombinant HIV-1 (pNL4-3) carrying either of the mutations have been generated. Genotypic and phenotypic analyses identified V108I as an unreported R82150-associated mutation. Both reverse transcriptase and viral resistance assays indicated that the resistance conferred by the V108I mutation is 7-fold less than that conferred by Y181C.

Total quality improvement according to hospital nursing executives

Total quality management (TQM) is certainly a hot topic in health care today. The Department of Veterans Affairs is not alone in launching the quality movement in their hospitals. The question is, can it succeed. The success of total quality lies in the commitment of the organizations' leaders. Nursing leadership has yet to be studied regarding TQM implementation. Nursing performs a vital role in hospitals, and if nursing leaders are opposed to total quality, then it is highly unlikely that the philosophy will succeed. This study is designed to measure the attitudes and perceptions of VA nursing chiefs regarding the total quality improvement (TQI) process.

Substituted naphthalenones as a new structural class of HIV-1 reverse transcriptase inhibitors

A novel substituted naphthalenone (TGG-II-23A) has been found that inhibits HIV-1 infection of CEM-SS cells at concentrations that are not cytotoxic. Time of addition experiments indicate that TGG-II-23A functions at a stage of the HIV-1 life cycle at or near reverse transcription. Cell free assays confirmed that TGG-II-23A inhibits HIV-1 reverse transcriptase. Similar to other non-nucleoside inhibitors, TGG-II-23A was specific for HIV-1 and failed to inhibit the replication of HIV-2. The binding site of TGG-II-23A appears to be in close proximity to that of the TIBO-like inhibitors, since a TIBO-resistant HIV-1 was also resistant to TGG-II-23A treatment. TGG-II-23A is a mixed non-competitive inhibitor that exhibits the same template:primer selectivity as other non-nucleoside inhibitors. TGG-II-23A therefore represents a new structural entry into the TIBO/Nevirapine class of inhibitors of HIV-1 reverse transcriptase.

Electrophoretic and Morphological Analysis of the Systematics of the Phalanger-Orientalis (Marsupialia) Species Complex in Papua-New-Guinea and the Solomon-Islands

Three electrophoretically and morphologically distinct populations previously referred to Phalanger orientalis are recognised within Papua New Guinea and the Solomon Islands: Phalanger orientalis orientalis from northern Papua New Guinea and some nearby offshore islands, Phalanger orientalis breviceps from the Bismarck Archipelago and Solomon Islands, and Phalanger intercastellanus from eastern and southern Papua New Guinea and the islands of Milne Bay. P. o. orientalis is genetically and geographically relatively uniform. P. o. breviceps may have been introduced by humans over most of its range, and it is extremely variable, even within island populations. P. intercastellanus shows considerable intraspecific geographic variation, and is genetically divergent from P. o. orientalis (Nei's unbiased distance of 0.216) and P. o. breviceps (Nei's unbiased distance of 0.171). Indeed, this divergence is so marked that the previously recognised taxa Phalanger carmelitae and Phalanger vestitus are apparently genetically closer to P. orientalis than to P. intercastellanus.

The adenohypophysis of the Australian lungfish, Neoceratodus forsteri--an immunocytological study

The cell types in the adenohypophysis of Neoceratodus resemble closely those already described for Lepidosiren and Protopterus. Four of these were immunocytochemically identified as prolactin cells, gonadotropes, corticotropes, and melanotropes. Antiserum to bullfrog growth hormone could not distinguish between prolactin cells and somatotropes. Anti-bullfrog prolactin, however, did selectively stain the prolactin cells, which allowed the identification of the somatotropes. The presumptive thyrotropes, as the only remaining cell type in the pars distalis, can then be tentatively identified by default. Likewise a PAS-positive cell type in the pars intermedia had no immunoreactivity to any of the antisera used. The functional significance of this cell remains to be demonstrated. One of the more unexpected findings was the presence of large numbers of cells immunoreactive to alpha-MSH in the proximal pars distalis. The implications of the presence of these cells in adult lungfish are discussed. The distribution of cell types within the pituitary of Neoceratodus showed more regionalization than is present in the other lungfish and corresponded more closely to that described for primitive actinopterygian fish. The general structure of the pituitary of Neoceratodus also resembled primitive actinopterygian fish more closely than it did amphibians, unlike the pituitaries of Lepidosiren and Protopterus. The evolutionary significance of this is also discussed.

Analytical method for the analysis and simulation of human locomotion

An all purpose computer algorithm used in the analysis and simulation of human locomotion is presented. The utility of the program "DYAMUS" stems from its simplicity in defining the initial configuration of the human model through a configuration graph called the "tree-array," and the handling of individual cases of human locomotion through separate sets of constraints conditions. Both the forward and inverse dynamical problems are presented together with the accommodation of kinematical experimental data. Closed-loops, linear and nonlinear springs and dampers at the joints, friction forces, and other external forces are easily incorporated. The selection of mathematical constraint equations to predict the human behavior during normal walking (gait) is presented. The intention of this paper is to emphasize how the constraints equations play a major role in the simulation of human locomotion once the dynamical equations of motion for a particular model are developed.

The identification of serum tuftsin by reverse-phase high-performance liquid chromatography and mass spectrometry

We describe for the first time a method for unambiguously identifying the phagocytic stimulating tetrapeptide tuftsin from trypsinized human serum. The method consists of separating serum tuftsin by reverse-phase (RP)-HPLC, collecting HPLC fractions corresponding to the synthetic tuftsin retention time, and then subjecting those fractions to mass spectrometry/mass spectrometry (MS/MS) analysis, which provides optimal molecular specificity to the measurement. Although quantification was not the goal, it was estimated that the amount of tuftsin found by RP-HPLC and MS/MS was in the hundreds of nanograms per milliliter.

Adult-onset hemiplegia: changes in gait after muscle-balancing procedures to correct the equinus deformity

Fifty-four adult patients with acquired spastic equinus and equinovarus deformity were treated with lengthening of the Achilles tendon, lateral transfer of the anterior tibial tendon, and appropriate muscle releases. All patients had preoperative dynamic electromyography and electrogoniometry performed in order to assist in planning the surgical procedures and to provide a baseline assessment of the dynamic deformities. Preoperatively, the stance and double-support phases of gait were prolonged. Throughout the stance phase, the gait of these patients was characterized by equinus deformity of the ankle, decreased flexion of the knee (hyperextension in the most severely involved patients), and increased flexion of the hip (which also varied with the severity of the equinus deformity of the ankle and hyperextension of the knee). In all patients, the operation was performed at least one year after onset of the hemiplegia. Clinical follow-up at an average of thirty months (range, twenty-four to sixty-two months) showed that the equinus deformity was corrected in all patients and that 59 per cent of them were brace-free. Two patients had a superficial infection that healed uneventfully, and two had pull-out of the tendon that required reoperation. Postoperative analyses of gait, performed at least one year after surgery for twenty-seven of the patients, showed that the stance and double-support phases of gait (which had been prolonged before surgery) approached the findings in normal control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Temporal gait monitoring: a new device

A new device that provides continuous recording of gait and gait events is presented. It can be used with motor point electromyography to perform walking electromyography, an electrogoniometer to continuously record joint position, or other measuring devices to record events or activities related to phase of gait. The major advantages of this system as compared with available systems are ease of use, decreased patient encumbrance, potential for portability, potential for digitizing the signal for minicomputer compatibility, and greatly reduced expense.

The gait abnormality of Huntington's disease

We investigated 13 patients with Huntington's disease and assessed gait by filming and by gait analyzer before and after increasing haloperidol dosage, until chorea was suppressed or side effects intervened. The severity of chorea and ataxia was scored blindly from videotapes. Gaits were abnormal in 12 of 13 patients and 5 of 6 patients who had symptoms for less than 5 years. Clinical characteristics included wide-based station, lateral swaying, spontaneous knee flexion, variable cadence, and parkinsonian features. Biomechanical analysis illustrated that gait characteristics varied in each walk, with a mean decrease in velocity, stride length, and cadence. Haloperidol treatment decreased chorea but did not affect gait patterns. Ataxia occurs early in the disease, has a distinct but variable pattern, is unrelated to chorea, and is not improved by haloperidol.

Measurement of enkephalin peptides in canine brain regions, teeth, and cerebrospinal fluid with high-performance liquid chromatography and mass spectrometry

Endogenous enkephalin pentapeptides are measured with unambiguous molecular specificity in canine and human tissue and fluid extracts. Both field desorption and fast atom bombardment mass spectrometry have been used to produce a protonated molecular ion of the peptide high-performance liquid chromatography fraction. The protonated molecular ion is subjected to collision-activated dissociation processes and a linked-field scan (B/E) selects a unique amino acid sequence-determining ion for monitoring and measurement. Stable isotope-incorporated peptide internal standards are used for quantification. Endogenous enkephalins are measured in hypothalamus, cerebrospinal fluid, pituitary, caudate nucleus, and tooth pulp extracts. Part-per-billion levels of endogenous peptide are measured.

Qualitative and quantitative gait phase analysis by continuous monitoring of inter-ankle distance

A new device is presented that is able to provide a temporal recording of gait as well as a continuous qualitative monitoring of gait events. It can be used with motor-point electromyography to perform walking electromyography, with an electrogoniometer to record joint position, or with other measuring devices to record events relative to phase of gait. The major advantages of this system as compared with available systems are ease of use, decreased patient encumbrance, potential for portability, greatly reduced expense, and the potential for digitizing the signal for computer compatibility. Preliminary data are comparable to available accepted norms.

High-performance liquid chromatographic and field desorption mass spectrometric measurement of picomole amounts of endogenous neuropeptides in biologic tissue

A unique combination of chromatographic separation and mass spectrometric techniques has been developed for a novel method for measurement of picomole amounts of endogenous oligopeptides in biologic tissue. High-performance liquid chromatography is utilized for rapid high-resolution separation of peptides. A new buffer system using dilute triethylamine-formic acid is utilized. The buffer system possesses excellent UV transparent properties enabling femtomole sensitivity for measurement of standard solutions of somatostatin. Use of porous polystyrenedivinylbenzene copolymer and octadecylsilyl columns facilitate retention of a peptide fraction from biologic extracts. Advantage was taken of field desorption mass spectrometric methods to eliminate chemical derivatization of peptides and to produce protonated molecular ions which retain total molecular information of the peptide. Use of appropriate internal standards and selected ion monitoring methods enabled nanogram sensitivity and, more importantly, optimized structural specificity of the compound being quantified. Results are compatible with radioimmunoassay data. Data obtained with field desorption mass spectrometry provide, for the first time, measurement of intact, chemically underivatized oligopeptides extracted form biologic matrices and significantly, provide and analytic method to calibrate radioimmunoassay data. This novel combination of methods is being applied to measurements of peptide (leu-enkephalin, met-enkephalin, somatostatin, etc.) in canine brain regions and dental pulp tissue.

Contribution of myocardial contractility to myocardial perfusion

Myocardial contractility in open-chest anesthetized (sodium pentobarbital) dogs was varied while ventricular pressure, coronary perfusion pressure, and coronary tone were held constant. Under those conditions, changes in regional blood flow should reflect changes only in intramyocardial compression related to the altered inotropic state. Increasing contractility with isoproterenol caused flow to decrease in the outer myocardial layers without change at the subendocardium. When contractility was decreased with pentobarbital, flow at the subendocardium was increased with little change in the outer layers. By manipulating perfusion pressure in the latter experiments it was demonstrated that subendocardial compression was falling from a starting value that was somewhat above peak ventricular pressure.

Somatosensory evoked potentials, cerebral blood flow and metabolism following cerebral missile trauma in monkeys

Somato sensory evoked potentials (SEP), cerebral blood flow and cerebral metabolism were studied in seven rhesus monkeys before and after a right occipito-frontal missile injury with an air rifle. The sensory evoked potential was present shortly after injury though markedly altered in shape. There was a very close correlation (r2 equal to 0.83) between SEP and cerebral blood flow on the uninjured side five minutes after injury. On the injured side, this was also noted but the amplitude of the SEP was much smaller, perhaps due to direct injury. If the flow in either hemisphere fell below 15-20 mls/100 gm/min, the evoked response disappeared, but in several animals a subsequent increase in flow was associated with a return of electrical activity. There was no correlation with cerebral perfusion pressure or cerebral metabolic rates for oxygen or lactate production, though it is likely that this is not due to physiological reasons but rather methodological. It might be inferred from these results that adequate flow is vital for the preservation and return of electrical activity following brain injury.