Antimicrobial susceptibility of mastitis pathogens from first lactation and older cows

Increasing antimicrobial resistance has become a serious concern worldwide and antimicrobial use in animal agriculture is currently under scrutiny. Mastitis is the most common reason for antibiotic use in dairy herds and thus, antimicrobial resistance of mastitis pathogens has received recent attention. The purpose of this study was to describe and compare antimicrobial susceptibility of mastitis pathogens isolated at calving from first lactation and older cows. A total of 202 bacteria were isolated from intramammary infections (IMIs) within 3 days after calving over a 16-month study period in the Krauss Dairy Research Herd at the Ohio Agricultural Research and Development Center (OARDC) in Wooster, OH. Of these IMIs, 78% were caused by coagulase-negative staphylococci (CNS). Forty-four percent of them were resistant to at least one antibiotic. Most resistance was observed against penicillin, 39% of the isolates from older cows and 26% from first lactation cows being resistant to penicillin (P > 0.05). Also MIC90 for penicillin was higher among isolates from older cows. On the other hand, resistance to tetracycline was more common and MIC90 higher among isolates from first lactation cows than from older cows. Differences in the proportions of resistant isolates between first lactation and older cows were not statistically significant, though. The resistance patterns of the CNS isolated during the study are concordant with antimicrobial usage in the study herd. This is in agreement with the generally accepted notion that selection pressure from the use of antibiotics is a main factor in development of antibiotic resistance.

Growth responses of Escherichia coli to immunoglobulin G from cows immunized with ferric citrate receptor, FecA

Effects of purified immunoglobulin (Ig) G from cows immunized with ferric citrate receptor, FecA, on the in vitro growth of Escherichia coli were investigated. Twenty-one cows were assigned to one of 3 treatments: 1) FecA immunization, 2) E. coli J5 bacterin immunization, and 3) unimmunized control. FecA was derived from E. coli UT5600/pSV66. Immunoglobulin G was purified from pooled colostral whey for each treatment group. The IgG from FecA immunized cows had higher titers against FecA compared with other treatment groups. Bacterial isolates tested were 14 E. coli from intramammary infections and E. coli UT5600/pSV66. Iron depletion decreased the growth of E. coli compared with growth in Fe-replete medium. The presence of IgG further decreased the growth compared with the growth under iron restriction alone. Bacterial growth did not differ among IgG sources nor between IgG concentrations. Replenishing media with exogenous iron overrode the inhibitory effects of the Fe-depletion and IgG. Vaccinating cows with FecA had little effect on the growth inhibitory properties of IgG toward E. coli mastitis isolates cultured in Fe-deplete media.

Changes in Vitamin C Concentrations in Plasma and Milk from Dairy Cows After an Intramammary Infusion of Escherichia coli

Plasma and milk concentrations of ascorbic acid and dehydro-L-ascorbic acid (DHAA) were measured before and after 21 Holstein cows (approximately 26 DIM) were given an intramammary infusion of Escherichia coli. Blood, milk from the unchallenged quarters, and milk from the challenged gland were sampled immediately before challenge (d 0) and 24 h and 7 d postchallenge. Plasma vitamin C (ascorbic acid + DHAA) concentrations decreased 39%, and concentrations of vitamin C and ascorbic acid in milk from the challenged quarter decreased 52 and 62%, respectively, in samples taken 24 h postchallenge. No change was observed in vitamin C concentrations in milk from unchallenged quarters. The concentration of DHAA in milk from challenged quarters increased 67% 24 h postchallenge. The duration of clinical mastitis, peak body temperature, number of colony-forming units of E. coli isolated from the infected gland, and loss in milk yield were associated with a change in concentration of vitamin C in milk from the challenged quarter. Increased severity of clinical signs was associated with large decreases in concentration of vitamin C in milk from the challenged quarter. Similar, but statistically weaker, relationships were observed for changes in plasma vitamin C concentrations.

Is the public equipped to act in out of hospital cardiac emergencies?

STUDY OBJECTIVE

This study aimed to determine whether the people in Australia are informed about and prepared to intervene in a cardiac emergency.

METHODS

A cross sectional telephone survey, which contained sections regarding participant demographics, cardiopulmonary resuscitation (CPR) training, knowledge of CPR, and the emergency contact number and potential barriers to performing chest compressions and mouth to mouth.

RESULTS

A total of 1489 people completed the questionnaire. Only 11% of the population had recently (<12 months) trained in CPR. When presented with a cardiac arrest scenario most participants stated that they would telephone 000. Significantly more respondents believed that they would give mouth to mouth to a family member compared with a stranger. A bleeding victim and fear of not having the skills were the most common barriers that reduced the participants perceived willingness to perform chest compressions and mouth to mouth.

CONCLUSION

This study suggests that a low percentage of the public is currently trained in CPR and also that they are unprepared to act in a cardiac emergency.

Opsonic activity of serum and whey from cows immunized with the ferric citrate receptor

The effects of immunizing dairy cows with the ferric citrate receptor, FecA, on the opsonic activity of serum and whey were measured in a phagocytosis assay. Fifteen cows were assigned to five blocks of three cows based on date of expected parturition. Cows within a block were randomly assigned to one of three treatments: 1) FecA immunization, 2) immunization with a commercially available Escherichia coli J5 bacterin, and 3) unimmunized controls. Cows were challenged at approximately 21 DIM by intramammary infusion of E. coli 727 into one mammary quarter. Escherichia coli 727 were opsonized for the phagocytosis assay with either 10% heat-inactivated serum or 50% heat-inactivated whey collected from each cow at calving, immediately before challenge and 7 d after challenge. Cows immunized with FecA or the E. coli J5 bacterin had increased IgG titers against FecA and E. coli 727 compared with unimmunized control cows. However, sera and whey collected from cows immunized with FecA did not enhance opsonization of E. coli 727 compared with sera and whey from control cows. Immunization with the E. coli J5 bacterin increased opsonization of sera greater than immunization with FecA. Immunoglobulin M antibody titer against E. coli 727 in whey and phagocytic indexes were positively correlated. The phagocytic index of whey immediately before challenge and 7 d after challenge were negatively associated with peak bacterial counts in mammary quarters challenged with E. coli 727. Results of the current trial suggest that the immune response resulting from immunization with FecA did not enhance opsonization and in vitro phagocytosis of E. coli 727.

Effect of immunoglobulin G from cows immunized with ferric citrate receptor (FecA) on iron uptake by Escherichia coli

The effects of immunoglobulin (Ig) G from cows immunized with the ferric citrate receptor (FecA) on iron uptake by Escherichia coli were investigated. Receptor FecA was purified from E. coli UT5600/pSV66. Cows were immunized with 400 microg purified FecA three times at 21 d intervals during late lactation and the nonlactating period. Immunoglobulin G was purified by protein G affinity chromatography from colostral whey from cows immunized with FecA and from unimmunized control cows. The purified IgG from FecA immunized cows had higher IgG titers against FecA compared with control IgG. Fifteen E. coli isolated from intramammary infections and E. coli UT5600/pSV66 were grown in an iron-depleted medium containing 1 mM citrate to induce FecA. The bacterial cells were mixed with 0, 2, and 4 mg/ml purified IgG, and 55Fe was added to the assay. After 5, 10, and 15 min incubations at 37 degrees C, samples were passed through 0.45-pm pore size filters. Filters were washed with saline three times, and the radioactivity of 55Fe taken up by the bacterial cells on the filters was measured by a liquid scintillation counter. The measurements were expressed as numbers of 55Fe atoms per colony-forming unit and transformed to log10. The assay was repeated three times for each isolate in a partially balanced incomplete block design. The presence of IgG decreased 55Fe uptake by E. coli mastitis isolates and E. coli UT5600/pSV66. Anti-FecA IgG reduced 55Fe uptake by E. coli greater than IgG from unimmunized cows.

Bacillus anthracis evolution and epidemiology

Bacillus anthracis is a pathogen that is widely distributed around the globe. However, this great distribution is not accompanied by great genetic diversity. Although subtle morphological and biochemical differences exist, the underlying genetic basis for this plasticity is not known. Indeed, very few single nucleotide differences have been detected among isolates and the only documented high variable sequences are associated with variable number tandem repeated (VNTR) sequences. The differences among the VNTRs has been used to suggest phylogenetic relationships among the worldwide isolates. There is one major clonal split in B. anthracis (A and B), with two minor clusters established within the B branch and four or more minor branches within the A group. The A branch is the most common worldwide, though the B branch is locally important in certain areas. The ecology and the evolution of B. anthracis have been greatly influenced by the spore phase of the lifecycle.

Phagocytosis and serum susceptibility of Escherichia coil cultured in iron-deplete and iron-replete media

The susceptibility of Escherichia coli cultured in either iron-deplete or iron-replete media to phagocytosis by bovine neutrophils and the bactericidal activity of bovine serum was tested in vitro. Fourteen E. coli isolates from naturally occurring intramammary infections (IMI) were cultured overnight at 37 degrees C in iron-replete media and iron-deplete media. The iron-replete media were trypticase soy broth or a chemically defined medium. The iron-deplete media were either trypticase soy broth plus 0.2 mM alpha, alpha' dipyridyl and 1mM citrate, or the chemically defined medium plus 0.2 mM alpha, alpha' dipyridyl, and 1 mM citrate. Iron-replenished medium was the chemically defined iron-deplete medium plus 40 mM ferric citrate. Bacteria grown in iron-deplete media were less susceptible to phagocytosis compared with bacteria grown in iron-replete media. Replenishing the chemically defined iron-deplete medium with ferric citrate obliterated the decreased susceptibility to phagocytosis observed in iron-deplete media. The iron availability in media used to culture E. coli before assay did not affect the bactericidal action of either the classical pathway of complement or the antibody independent alternative pathway of complement in serum. The growth of bacteria in iron-deplete medium did not alter the expression of capsule compared with growth in iron-replete medium. Iron availability during culture of E. coli altered the susceptibility of isolates to phagocytosis by neutrophils, but had no effect on the susceptibility of isolates to the bactericidal activity of serum.

Efficacy of immunization with ferric citrate receptor FecA from Escherichia coli on induced coliform mastitis

The effects of immunization with the ferric citrate receptor FecA on antibody responses and on experimentally induced mastitis following intramammary challenge were investigated. Twenty-one cows were assigned to seven blocks of three cows based on expected parturition. Cows within block were randomly assigned to one of three treatments: 1) FecA immunization, 2) Escherichia coli J5 immunization, and 3) unimmunized controls. Challenge was by infusion of approximately 60 cfu of E. coli 727 into one uninfected mammary gland between 13 and 31 d after parturition. Cows within block were challenged on the same day. Cows immunized with FecA had higher immunoglobulin (Ig)G titers against FecA in serum and in mammary secretions at calving, immediately before challenge, and 7 d after challenge than did cows immunized with E. coli J5 or control cows. Immunization with FecA also increased IgG titers against whole-cell E. coli 727 in serum and in mammary secretions at calving. Serum IgM titers against FecA were higher in FecA immunized cows than in other treatment groups immediately before challenge. Bacterial counts in milk, duration of bacterial isolation in milk, rectal temperature, and milk somatic cell counts following intramammary challenge were similar among treatments. Milk production and dry matter intake did not differ among treatments. The ferric citrate receptor FecA was immunogenic in cows, but immunization had minimal effect on the clinical severity of experimentally induced E. coli mastitis.

Molecular investigation of the Aum Shinrikyo anthrax release in Kameido, Japan

In 1993, the Aum Shinrikyo cult aerosolized Bacillus anthracis spores over Kameido, Japan. Spore samples were obtained from the release site, cultured, and characterized by molecular genetic typing. The isolates were consistent with strain Sterne 34F2, which is used in Japan for animal prophylaxis against anthrax.

Nitric oxide enhancement of fludarabine cytotoxicity for B-CLL lymphocytes

Fludarabine is active but not curative in the treatment of chronic lymphocytic leukemia (B-CLL). Nitric oxide (NO) supplied from exogenous, NO-donating pro-drugs can also induce apoptosis and death of acute leukemia cells. This study investigated combinations of fludarabine with NO-donating pro-drugs for their cytotoxicity against freshly isolated B-CLL lymphocytes following a 72 h exposure in vitro. The median IC(50)for fludarabine was 2.2 microM (n = 85). The nitric oxide donors DETA-NO, PAPA-NO, and MAHMA-NO were also cytotoxic, and their effects were inversely related to rates of NO release. Neither DETA-NO depleted of NO nor DETA itself was effective, indicating that NO was required for cytotoxicity. Drug interactions were evaluated by a modified combination index method. Synergy was observed in combinations of fludarabine or nelarabine (506U78) with DETA-NO in 52% and 88% of samples, respectively. Interestingly, the combination of fludarabine and DETA-NO was more cytotoxic in B-CLL cells less sensitive to fludarabine. DETA-NO did not enhance the activity of other DNA anti-metabolites, topoisomerase I and II inhibitors, or alkylating agents. Finally, the anti-leukemic activity of fludarabine alone or in combination with DETA-NO was found to correlate with inhibition of cellular RNA synthesis. These results indicate that NO donors could enhance fludarabine therapy for B-CLL.

Effects of a community-based intervention to increase activity in American Indian elders

The purpose of this study was to evaluate the efficacy of a community-based exercise course applied to a group of American Indians (AI) who, because of physician recommendation and/or self-motivation, desired to increase their physical activity. Changes in physiological measurements and self-perceived measurements were determined following a moderate-intensity exercise program implemented through a randomized controlled trial to a population of American Indian elders between the ages of 55 and 75 living in an urban area. It was hypothesized that the exercise subjects would show improvement in all of the study variables examined, including three subjective measurements in emotional health, seven subjective measurements in physical health, and several physiological indices. The subjects participated in a six-week exercise class designed for healthy elderly persons as well as for those struggling from arthritis, heart disease, obesity, and/or non-insulin dependent diabetes. Results were measured using both subjective self-perceived and objective physiological measurements; T-tests were used to analyze the data, using subjects as their own controls and using a separate control group. Following the intervention, the exercise participants significantly improved their self-perceived physical health (p = 0.001), emotional health (p = 0.023), and personal appearance (p = 0.025) when compared with baseline values. The exercise subjects also significantly increased the self-perceived frequency with which they performed chores that gave them exercise (p = 0.035) and significantly increased the self-perceived frequency that they participated in activities specifically for exercise (p = 0.023) when compared with pre-intervention measurements. A corresponding trend in objective indices was also observed: following the intervention period, exercise participants were found to significantly lower their systolic blood pressure (p = 0.046) and significantly lower their respirations (p = 0.048) as compared with initial values. Findings of this study suggest that senior Al adults who participated in the exercise program subjectively and objectively improved their health status. The authors think that this type of program would be an excellent resource for physicians to recommend to their eldrly patients in need of increased physical activity. A literature search found no previously published clinical data documenting the response of Al elders to excercises that developed flexibility, muscular strength, and muscular endurance.

Intraspecific comparisons reveal differences in the pattern of ultraviolet radiation responses in four maize (Zea mays L.) varieties

Four maize (Zea mays L.) varieties were examined for ultraviolet radiation-induced changes in leaf rolling, biomass, fluctuating leaf asymmetry and DNA damage. Short-term dose-response curves for each response were constructed and responses in each line compared. The four varieties each exhibited a different pattern of tolerance and reactivity, ranging from B73, which was tolerant in all four measures, to TS1, which was affected in DNA damage levels and leaf rolling but unaffected in biomass accumulation and fluctuating leaf asymmetry. The pattern of ultraviolet radiation responses allows us to narrow the possibilities for the source of the defect in reactive varieties. The four varieties tested include inbred parents that have been used to construct recombinant inbred lines and a variety that is found in the background of the engineered RescueMu transposon mutagenesis lines. These dose-response curves and variety comparisons provide the foundation for genetic dissection of the mechanisms of ultraviolet radiation responses in maize.

Francisella tularensis strain typing using multiple-locus, variable-number tandem repeat analysis

Francisella tularensis, the etiological agent of tularemia, is found throughout the Northern hemisphere. After analyzing the F. tularensis genomic sequence for potential variable-number tandem repeats (VNTRs), we developed a multilocus VNTR analysis (MLVA) typing system for this pathogen. Variation was detected at six VNTR loci in a set of 56 isolates from California, Oklahoma, Arizona, and Oregon and the F. tularensis live vaccine strain. PCR assays revealed diversity at these loci with total allele numbers ranging from 2 to 20, and Nei's diversity index values ranging from 0.36 to 0.93. Cluster analysis identified two genetically distinct groups consistent with the current biovar classification system of F. tularensis. These findings suggest that these VNTR markers are useful for identifying F. tularensis isolates at this taxonomic level. In this study, biovar B isolates were less diverse than those in biovar A, possibly reflecting the history of tularemia in North America. Seven isolates from a recent epizootic in Maricopa County, Ariz., were identical at all VNTR marker loci. Their identity, even at a hypervariable VNTR locus, indicates a common source of infection. This demonstrates the applicability of MLVA for rapid characterization and identification of outbreak isolates. Future construction of reference databases will allow faster outbreak tracking as well as providing a foundation for deciphering global genetic relationships.

Characteristics and management practices associated with milk production in dairy herds in Ohio enrolled in official Dairy Herd Improvement Association programs

OBJECTIVE

To determine herd characteristics and management practices associated with milk production in dairy herds enrolled in official Dairy Herd Improvement Association (DHIA) programs in Ohio.

SAMPLE POPULATION

186 dairy farms in Ohio.

PROCEDURE

All herds in official DHIA programs in 9 counties were invited to participate. Information regarding herd characteristics and management practices was obtained, using a standardized questionnaire. Bulk-tank milk samples were obtained for bacteriologic culture. Official DHIA test-day records were obtained, and associations were identified, using multivariable ANOVA procedures.

RESULTS

Of 479 eligible producers, 186 (39%) participated, and consecutive bulk-tank milk samples were available for culture from 172 (36%). Streptococcus agalactiae and Mycoplasma spp were not recovered from bulk-tank milk samples, but Staphylococcus aureus was recovered from 64 (37%) herds. Mean (+/- SD) number of lactating cows in participating herds was 97+/-66, with 123 (66%) herds milking < 100 cows. The RHA was significantly associated with number of cows in milk, estimated percentage of herd detected in estrus, reported annual percentage of heifer calves born alive that died before 8 weeks old, percentage days in milk, use of bovine somatotropin during the preceding 2 years, and sex of the person completing the questionnaire.

CONCLUSIONS AND CLINICAL RELEVANCE

In this study, the strongest indicator of milk production was number of cows in milk. However, merely adding cows to a herd should not be considered to guarantee increased milk production, because other management traits could be confounded with increased number of cows in a herd.

Breast cancer: variables affecting sentinel lymph node visualization at preoperative lymphoscintigraphy

PURPOSE

To compare patients with visualized sentinel lymph nodes (SLNs) and patients with nonvisualized SLNs, with a focus on variables affecting SLN visualization at preoperative lymphoscintigraphy and on nodal drainage basins as related to tumor location.

MATERIALS AND METHODS

One hundred thirty-six patients who had breast cancer underwent preoperative lymphoscintigraphy before SLN biopsy. Patients with visualized and nonvisualized SLNs were compared for age; tumor site, size, and histologic findings; injection guidance method; diagnostic biopsy type; interval between biopsy and lymphoscintigraphy; intraoperative identification method; and surgical identification rate. Visualized SLN drainage basins were noted.

RESULTS

Ninety-nine patients had visualized and 37 had nonvisualized SLNs, without statistically significant differences in tumor site, size, and histologic findings; injection guidance method; diagnostic biopsy type; and interval between biopsy and lymphoscintigraphy. Ninety-nine (73%) of the 136 SLNs were visualized at lymphoscintigraphy; 30 (81%) of the 37 nonvisualized SLNS were identified at surgery. Of the seven SLNs not identified at surgery, five were mapped with radiocolloid only. Patients with nonvisualized SLNs were older than those with visualized SLNs. Eleven (46%) of 24 tumors with internal mammary drainage were in the outer part of the breast.

CONCLUSION

Patients with and those without visualization differed in age, SLN identification at surgery, and surgical identification method. Nonvisualized status does not preclude axillary metastasis. In older patients with nonvisualized SLNs, blue dye may aid in SLN detection, as compared with isotope-only localization.

Asystolic cardiac arrest in Melbourne, Australia

OBJECTIVE

To study the outcome of victims of out-of-hospital cardiac arrest presenting to the Metropolitan Ambulance Service in asystole, in Melbourne, Australia.

METHODS

A retrospective case-note review of all patients presenting to the Metropolitan Ambulance Service in asystole for 1997 was performed. Metropolitan Ambulance Service case notes and hospital records were examined to determine the presenting rhythm and the patients' outcome.

RESULTS

In a 12-month period, 778 patients met the entry criteria. Age mean was 67 years, 36% female, 64% male. Metropolitan Ambulance Service response time to scene time was a mean of 9.76 min. Resuscitation was commenced on 37% of patients. There was one survivor (0.12%).

CONCLUSION

Adult victims of out-of-hospital cardiac arrest presenting as asystole should not receive treatment.

Results from the first 12 months of a fire first-responder program in Australia

STUDY OBJECTIVE

We aimed to reduce response times and time to defibrillation for out-of-hospital cardiac arrest patients through fire first-responders equipped with automatic external defibrillators (AEDs). The fire first-responders were added as an extra tier to the existing two-tired ambulance response.

METHODS

This prospective controlled trial set in Melbourne, Australia, consisted of a control area (277 km2, population density 2343/km2-ambulance only dispatch) and a pilot area (171 km2, population density 2290/km2-ambulance and fire first-responder dispatch). The main outcome measures were time to emergency medical service (EMS) arrival at scene for all cardiac arrest patients and time to defibrillation for cardiac arrest patients presenting in ventricular fibrillation (VF). The study participants were patients who suffered a cardiac arrest of presumed cardiac aetiology for which a priority 0 emergency response was activated. A total of 268 patients were located in the control area and 161 in the pilot (intervention) area.

RESULTS

The mean response time to arrival at scene was reduced by 1.60 (95% CI 1.21, 1.99) min, P < 0.001. A large reduction in prolonged responses (> or = 10 min) to cardiac arrests was also observed in the pilot area (2%) compared with the control area (18%), chi = 23.19, P < 0.001. Mean time to defibrillation was reduced by 1.43 (95% CI 0.11, 2.98) min, P = 0.068.

CONCLUSION

The results from this study suggest that fire officers can be successfully trained in the use of AEDs and can integrate well into a medical response role. The combined response of ambulance and fire personnel significantly reduced the response interval and reduced time to defibrillation. This suggests that in appropriate situations other agencies could be considered for involvement in co-ordinated first-responder programs.

Neuronal activity and the establishment of normal and epileptic circuits during brain development

The question we attempted to address in this chapter is: Do brief but recurrent seizures in early life alter the ontogeny of hippocampal networks in ways that produce epileptic circuits? Results from the tetanus toxin model suggest that this is likely the case. Following seizures in Postnatal Weeks 2 and 3, most adult rats have a focal epilepsy that arises from hippocampus. Recordings from hippocampal slices support this conclusion since they demonstrated the occurrence of spontaneous network discharges in normal artificial cerebrospinal fluid. Moreover, when GABA-A receptor-mediated synaptic transmission was suppressed, slices from adult epileptic rats produced prolonged electrographic seizures which are never observed in control rats. This suggests that hyperexcitable recurrent excitatory networks contribute to hippocampal seizures in this model. In light of this, anatomical results from biocytin-filled neurons were surprising. Results suggest that recurrent axon arbors neither sprout additional branches as a result of seizure activity nor maintain their exuberant branching patterns of early life. Thus, excessive connectivity cannot explain seizure generation. Axon arbors either remodel in normal ways or prune additional collaterals as a result of ongoing epileptiform discharging. At the same time that axon arbors remodel, the dendrites of these cells have decreased dendritic spine density, suggesting a partial deafferentation. While a complete understanding of the origins of spine loss requires further investigation, we hypothesize that this loss is a product of a partial deafferentation that occurs due to excessive and abnormal selection of synaptic connections. Network-induced heterosynaptic LTD of noncoincidentally active afferants may be one mechanism that leads to a loss of synapses. Moreover, competition among and selection between individual recurrent excitatory synapses may contribute to spine loss as well. The "winners" of this competition, the most potent and effective early-formed recurrent excitatory synapses, are likely key contributors to seizure generation in this model and possibly in humans with early-onset temporal lobe epilepsy.

Survival of dentate hilar mossy cells after pilocarpine-induced seizures and their synchronized burst discharges with area CA3 pyramidal cells

The clinical and basic literature suggest that hilar cells of the dentate gyrus are damaged after seizures, particularly prolonged and repetitive seizures. Of the cell types within the hilus, it appears that the mossy cell is one of the most vulnerable. Nevertheless, hilar neurons which resemble mossy cells appear in some published reports of animal models of epilepsy, and in some cases of human temporal lobe epilepsy. Therefore, mossy cells may not always be killed after severe, repeated seizures. However, mossy cell survival in these studies was not completely clear because the methods did allow discrimination between mossy cells and other hilar cell types. Furthermore, whether surviving mossy cells might have altered physiology after seizures was not examined. Therefore, intracellular recording and intracellular dye injection were used to characterize hilar cells in hippocampal slices from pilocarpine-treated rats that had status epilepticus and recurrent seizures ('epileptic' rats). For comparison, mossy cells were also recorded from age-matched, saline-injected controls, and pilocarpine-treated rats that failed to develop status epilepticus. Numerous hilar cells with the morphology, axon projection, and membrane properties of mossy cells were recorded in all three experimental groups. Thus, mossy cells can survive severe seizures, and those that survive retain many of their normal characteristics. However, mossy cells from epileptic tissue were distinct from mossy cells of control rats in that they generated spontaneous and evoked epileptiform burst discharges. Area CA3 pyramidal cells also exhibited spontaneous and evoked bursts. Simultaneous intracellular recordings from mossy cells and pyramidal cells demonstrated that their burst discharges were synchronized, with pyramidal cell discharges typically beginning first. From these data we suggest that hilar mossy cells can survive status epilepticus and chronic seizures. The fact that mossy cells have epileptiform bursts, and that they are synchronized with area CA3, suggest a previously unappreciated substrate for hyperexcitability in this animal model.

Correlates with comfort and function after total shoulder arthroplasty for degenerative joint disease

Although most patients are improved after shoulder arthroplasty, the degree of improvement is variable. The factors contributing to this variability are not well understood. In particular, little information is available regarding the preoperative characteristics of the patient that may influence the quality of the result. This study correlated patient demographics, preoperative health status, and preoperative shoulder function with 3 outcome metrics: comfort, physical role function, and shoulder-specific function. One hundred thirty-four shoulders having total shoulder arthroplasty for degenerative glenohumeral joint disease had an average follow-up of 3.4 +/- 1.8 years. The SF-36 Comfort score improved from 39 to 61 (P < .0001). The SF-36 Physical Role Function score improved from 30 to 52 (P < .0001). The average number of Simple Shoulder Test functions performable (out of 12) improved from 4 to 9 (P < .0001). The strongest correlates with postoperative comfort included preoperative physical function (P < .0001), general health (P < .0001), and social function (P < .001). The strongest correlates with postoperative physical role function included preoperative physical function (P < .0001) and general health (P < .001). The strongest correlates with postoperative shoulder function included male gender (P < .0001), and preoperative physical function (P < .0001), social function (P < .0001), mental health (P < .0001) and shoulder function (P < .0001). These data indicate that the overall well-being of the patient before surgery is strongly correlated with the quality of the outcome from total shoulder arthroplasty for degenerative glenohumeral joint disease.

Neuro-endocrine biomarkers of pollution-induced stress in marine invertebrates

Nitric oxide (NO) is a molecular mediator of the non-specific immune response of vertebrates but production has also been recorded in response to bacterial infection in invertebrates. Together with biogenic amines and cytokines, production of NO in invertebrate phagocytic haemocytes is thought to represent a putative stress response. In this study the hypothesis that NO might be a sensitive biomarker of stress in invertebrates has been tested. The spectrophotometric Griess assay for nitrite and nitrate has been modified so that the final breakdown products of NO are suitable for measurement in invertebrate haemolymph. The assay was linear in the range 1-100 microM with a sensitivity of 4 microM. The baseline NOx measurement in unstressed mussels was 0.74 mM NOx/mg protein. Mytilus edulis were kept at 15 micro C in filtered seawater for at least 2 days prior to exposure to TBTO (0.001-0.1 mg/l) for 24 h. Preliminary results suggest that TBTO perturbs the NO response and that the outlined assay protocol is a sensitive means of detecting those changes. It is proposed that NO measurements potentially offer a highly sensitive, non-invasive means of monitoring stress responses associated with environmental change.

Bacillus anthracis diversity in Kruger National Park

The Kruger National Park (KNP), South Africa, has a recorded history of periodic anthrax epidemics causing widespread disease among wild animals. Bacillus anthracis is the causative agent of anthrax, a disease primarily affecting ungulate herbivores. Worldwide there is little diversity among B. anthracis isolates, but examination of variable-number tandem repeat (VNTR) loci has identified six major clones, with the most dissimilar types split into the A and B branches. Both the A and B types are found in southern Africa, giving this region the greatest genetic diversity of B. anthracis worldwide. Consequently, southern Africa has been hypothesized to be the geographic origin of B. anthracis. In this study, we identify the genotypic types of 98 KNP B. anthracis isolates using multiple-locus VNTR analysis. Two major types are evident, the A branch and the B branch. The spatial and temporal distribution of the different genotypes indicates that anthrax epidemic foci are independent, though correlated through environmental cues. Kruger B isolates were found on significantly higher-calcium and higher-pH soils than were Kruger type A. This relationship between genotype and soil chemistry may be due to adaptive differences among divergent anthrax strains. While this association may be simply fortuitous, adaptation of A types to diverse environmental conditions is consistent with their greater geographic dispersal and genetic dissimilarity.

Do shoulder patients insured by workers' compensation present with worse self-assessed function and health status?

The purpose of this study was to test the hypothesis that patients whose shoulder problems are covered by workers' compensation insurance perceive worse shoulder function and health status than do comparable patients whose problem is not covered by workers' compensation. Each of 1063 consecutive patients presenting with shoulder problems to an individual consultant completed 2 questionnaires: the Simple Shoulder Test inventory of shoulder function and the Short Form 36 general health assessment. The patients were divided into 2 groups on the basis of whether care of the shoulder problem was covered by injured workers' compensation insurance. The results indicate that patients whose shoulder condition is covered by workers' compensation have significantly lower self-assessed shoulder function and health status than do those patients whose shoulder conditions are not related to on-the-job injuries. The differences between the workers' compensation and non-workers' compensation groups could not be attributed to differences in age, sex, or diagnosis.

A prospective, multipractice study of shoulder function and health status in patients with documented rotator cuff tears

A total of 191 patients from 29 orthopedic practices are analyzed in this report. All had full-thickness tears documented by imaging tests and/or surgical observation; 190 had tears of the supraspinatus, 54 had tears of the infraspinatus, and 13 had tears of the subscapularis. The greatest functional deficits were in the ability to place 8 pounds on a shelf at the level of the head (93% unable), the ability to throw overhand (93% unable), and the ability to sleep on the affected side (86% unable). The SF-36 physical role function and comfort scores were 27% and 48%, respectively, of those of age- and sex-matched controls. Of the variables suggested by a review of the literature, only female sex, involvement of the infraspinatus in the cuff tear, and workers' compensation claims were significantly correlated with lower shoulder function in this series of patients.

Herd characteristics and management practices associated with bulk-tank somatic cell counts in herds in official Dairy Herd Improvement Association programs in Ohio

OBJECTIVE

To identify herd characteristics and management practices associated with bulk-tank somatic cell counts (BTSCC) in dairy herds in Ohio enrolled in official Dairy Herd Improvement Association (DHIA) programs.

SAMPLE POPULATION

186 dairies in Ohio.

PROCEDURE

All herds in official DHIA programs in 9 counties were asked to participate. Extensive information regarding herd characteristics and management practices was obtained, using a standardized questionnaire. Bulk-tank milk samples were requested from all participating herds for bacterial culture. Official DHIA test-day records for January 1997 were obtained from all herds enrolled in official DHIA programs in the 9 counties. Potential associations were identified, using multivariable ANOVA.

RESULTS

Participation was 186 of 479 (39%) herds. Streptococcus agalactiae and Mycoplasma spp were not isolated from bulk-tank milk samples. Staphylococcus aureus was isolated from 64 of 172 (37%) of the herds. The BTSCC were inversely associated with peak daily milk production, postmilking teat disinfection, percentage of eligible cows in the herd detected in estrus, and directly related to the extent to which BTSCC was perceived as a herd problem during the preceding 2 years. Type of housing for nonlactating cows and product used for treatment of nonlactating cows also were significantly associated with BTSCC.

CONCLUSIONS AND CLINICAL RELEVANCE

Consideration of herd characteristics and implementation of management practices associated with BTSCC could result in increased milk yield and production of milk with lower BTSCC.

Association between measures of milk quality and risk of violative antimicrobial residues in grade-A raw milk

OBJECTIVE

To determine whether bulk-tank standard plate counts or plate loop counts and bulk-tank somatic cell counts (SCC) were associated with detection of violative antimicrobial residues in milk from dairy cattle.

DESIGN

Longitudinal study.

PROCEDURE

Information for 1994 through 1997 was obtained from a large milk marketing cooperative that operated in multiple states throughout the northeastern and midwestern United States (16,831 herd-years of information from 6,546 farms) and from the Ohio Department of Agriculture Grade-A Milk Certification Program (12,042 herd-years of information from 4,022 farms). Data were analyzed by use of multivariate logistic regression.

RESULTS

For both data sets, odds that a violative antibiotic residue would be detected increased as mean SCC for the herd-year increased. Standard plate counts and plate loop counts were not associated with odds that a violative antibiotic residue would be detected.

CONCLUSIONS AND CLINICAL RELEVANCE

Results of this study suggested that the odds that a violative antibiotic residue would be found in bulk-tank milk increased as mean SCC for the herd-year increased. This suggests that management practices that would be expected to influence SCC may also influence the risk of antibiotic residue violations.

Cross-species amplification, non-invasive genotyping, and non-Mendelian inheritance of human STRPs in Savannah baboons

Twenty-nine human microsatellite primer pairs were screened for their utility in the cross-species amplification of baboon DNA derived from both blood and feces as part of a larger study to identify paternal half sisters in a population of wild baboons (Papio cynocephalus). Forty-one percent (12/29) of the human primers successfully amplified baboon DNA. Of these 12 primers, six amplified fragments that were both polymorphic and heterozygous (mean number of alleles = 6, mean heterozygosity = 87%) and yielded repeatable results. However, only five of these six simple tandem repeat polymorphisms (STRPs) showed patterns of Mendelian inheritance (i.e., mothers and offspring shared at least one allele at each locus), and were therefore useful for determining relatedness between individuals. Analysis of the sixth primer revealed non-Mendelian inheritance, i.e., three of the six known mother-daughter pairs had no shared alleles. This failure was probably due to non-specific fragment amplification, and may have resulted from a different STRP locus being amplified in mother and daughter. This finding highlights the importance of sampling DNA from known parent-offspring pairs when screening microsatellite primers for genetic studies. Multiple, independent replications of genotypes and Mendelian checks are both particularly important when using cross-species amplification or when using a low-quality source of DNA.

The value of the axial view in assessing calcaneal fractures

We studied the value of the axial view of the calcaneum in diagnosing fractures. Fifty sets calcaneal radiographs were studied by four senior trauma staff and four orthopeadic trainees on two occasions 2-3 weeks apart. On the first occasion only the lateral view was studied; on the second, both lateral and axial views were studied. The axial view did not improve the sensitivity or specificity of the lateral view alone. Senior staff were more accurate in assessing the radiographs. We suggest that the axial view should not be used routinely in assessing a patient with a possible calcaneal fracture.

Fluvoxamine reduces physiologic reactivity to trauma scripts in posttraumatic stress disorder

This study assessed the effect of open-label fluvoxamine treatment for posttraumatic stress disorder (PTSD), depressive symptoms, and physiologic arousal to trauma cues. Baseline psychometric ratings and physiologic assessments of heart rate and blood pressure responses to individualized, taped trauma scripts were determined for 16 patients with PTSD and 16 mentally healthy age- and gender-matched control subjects exposed to at least 1 serious trauma. Patients with PTSD had greater autonomic reactivity than control subjects at baseline, with physiologic measures correlating with the severity of the PTSD for the combined groups. Discriminant analyses indicated that systolic blood pressure best classified patients with PTSD (75% sensitivity) and control subjects (100% specificity), with a stepwise discriminant analysis showing that combined physiologic variables correctly classified 75% of patients with PTSD and 100% of control subjects. After 10 weeks of fluvoxamine treatment (100-300 mg/day), patients' PTSD, depression, and physiologic reactivity improved significantly. Medicated patients with PTSD could not be distinguished statistically from untreated control subjects in any physiologic measure. This dampening of autonomic reactivity after drug treatment corroborates subjective measures of improvement, validating the reported efficacy of fluvoxamine in this open trial.

Controversies in sentinel lymph node biopsy for breast cancer

Sentinel lymph node biopsy, validated in melanoma staging, is currently under investigation for breast cancer staging. Reports suggest that the sentinel lymph node has a high predictive value in determining the presence of axillary metastases. Identification of a sentinel lymph node that is free of metastatic tumor cells may eliminate the necessity of performing a standard axillary lymph node dissection with its attendant morbidity. Numerous techniques are utilized to identify the sentinel node with approximately the same success rate. This paper will address some of the controversial areas of sentinel lymph node biopsy and offer an option for physicians who want to develop a sentinel lymph node program in their hospital.

Multiple-locus variable-number tandem repeat analysis reveals genetic relationships within Bacillus anthracis

Bacillus anthracis is one of the most genetically homogeneous pathogens described, making strain discrimination particularly difficult. In this paper, we present a novel molecular typing system based on rapidly evolving variable-number tandem repeat (VNTR) loci. Multiple-locus VNTR analysis (MLVA) uses the combined power of multiple alleles at several marker loci. In our system, fluorescently labeled PCR primers are used to produce PCR amplification products from eight VNTR regions in the B. anthracis genome. These are detected and their sizes are determined using an ABI377 automated DNA sequencer. Five of these eight loci were discovered by sequence characterization of molecular markers (vrrC(1), vrrC(2), vrrB(1), vrrB(2), and CG3), two were discovered by searching complete plasmid nucleotide sequences (pXO1-aat and pXO2-at), and one was known previously (vrrA). MLVA characterization of 426 B. anthracis isolates identified 89 distinct genotypes. VNTR markers frequently identified multiple alleles (from two to nine), with Nei's diversity values between 0.3 and 0.8. Unweighted pair-group method arithmetic average cluster analysis identified six genetically distinct groups that appear to be derived from clones. Some of these clones show worldwide distribution, while others are restricted to particular geographic regions. Human commerce doubtlessly has contributed to the dispersal of particular clones in ancient and modern times.

Novel hippocampal interneuronal subtypes identified using transgenic mice that express green fluorescent protein in GABAergic interneurons

The chief inhibitory neurons of the mammalian brain, GABAergic neurons, are comprised of a myriad of diverse neuronal subtypes. To facilitate the study of these neurons, transgenic mice were generated that express enhanced green fluorescent protein (EGFP) in subpopulations of GABAergic neurons. In one of the resulting transgenic lines, called GIN (GFP-expressing Inhibitory Neurons), EGFP was found to be expressed in a subpopulation of somatostatin-containing GABAergic interneurons in the hippocampus and neocortex. In both live and fixed brain preparations from these mice, detailed microanatomical features of EGFP-expressing interneurons were readily observed. In stratum oriens of the hippocampus, EGFP-expressing interneurons were comprised almost exclusively of oriens/alveus interneurons with lacunosum-moleculare axon arborization (O-LM cells). In the neocortex, the somata of EGFP-expressing interneurons were largely restricted to layers II-IV and upper layer V. In hippocampal area CA1, two previously uncharacterized subtypes of interneurons were identified using the GIN mice: stratum pyramidale interneurons with lacunosum-moleculare axon arborization (P-LM cells) and stratum radiatum interneurons with lacunosum-moleculare axon arborization (R-LM cells). These newly identified interneuronal subtypes appeared to be closely related to O-LM cell, as they selectively innervate stratum lacunosum-moleculare. Whole-cell patch-clamp recordings revealed that these cells were fast-spiking and showed virtually no spike frequency accommodation. The microanatomical features of these cells suggest that they function primarily as "input-biasing" neurons, in that synaptic volleys in stratum radiatum would lead to their activation, which in turn would result in selective suppression of excitatory input from the entorhinal cortex onto CA1 pyramidal cells.

Automatic external defibrillators: changing the way we manage ventricular fibrillation

OBJECTIVE

To discuss recent developments in automatic defibrillation and to review the evidence that first-responders equipped with automatic external defibrillators (AEDs) improve survival from out-of-hospital cardiac arrest.

DATA SOURCES

MEDLINE search from 1966 to 1999 (articles in English only) and examination of bibliographies.

STUDY SELECTION

Published studies of out-of-hospital cardiac arrest and first-responders equipped with AEDs. Studies had to have a control group and to report survival to hospital discharge from ventricular fibrillation (VF).

DATA EXTRACTION

Six studies met the selection criteria (two prospective randomised trials, two prospective controlled trials, and one cohort study and one retrospective study, both with historical controls).

DATA SYNTHESIS

A random effects meta-analysis of odds ratios for survival from VF.

CONCLUSIONS

Meta-analysis suggests that equipping first-responders with AEDs increases the probability of survival to hospital discharge after out-of-hospital cardiac arrest (odds ratio, 1.74; 95% CI, 1.27-2.38; P < 0.001). However, most of the studies lacked sufficient power to draw definitive conclusions. Until the impact of wide deployment of AEDs is fully understood, first-responder defibrillation in Australia should only occur as part of coordinated multicentre research studies.

Blockade of neuronal activity during hippocampal development produces a chronic focal epilepsy in the rat

During brain development, neuronal activity can transform neurons characterized by widely ranging axonal projections to ones with more restricted patterns of synaptic connectivity. Previous studies have shown that an exuberant outgrowth of local recurrent excitatory axons occurs in hippocampal area CA3 during postnatal weeks 2 and 3. Axons are remodeled with maturation, and nearly half of the branches are eliminated. Postnatal weeks 2 and 3 also coincide with a "critical" period of development, when CA3 networks have a marked propensity to generate electrographic seizures. In an attempt to prevent axonal remodeling, local circuit activity was blocked unilaterally in dorsal hippocampus by continuous infusion of tetrodotoxin (TTX). Field potential recordings from behaving animals were dramatically altered when TTX infusion was initiated at the beginning of the critical period, week 2, but not later in life. Spontaneous, synchronized spikes and electrographic seizures with behavioral accompaniments were observed after 4 weeks of TTX infusion and persisted into adulthood. When recordings were made during TTX infusion, synchronized spiking was recorded in ventral hippocampus as early as 2 weeks after infusate introduction. At this same time, extracellular field recordings from in vitro slices demonstrated spontaneous network-driven "mini-bursts" arising from ventral hippocampal slices. These were abolished by glutamate receptor antagonists. Whole-cell recordings from CA3 neurons revealed bursts of excitatory synaptic potentials coincident with the network bursts recorded extracellularly. Thus, local assemblies of mutually excitatory CA3 pyramidal cells are hyperexcitable in these rats. Whether alterations in developmental axonal remodeling mediate these effects awaits further studies.

Care for older persons. Are divisional programs meeting needs?

BACKGROUND

A national forum on healthy ageing was convened for divisions of general practice in November 1998.

OBJECTIVE

Views of delegates were sought regarding divisional programs for older people related to the following areas: working in collaboration; integration; the context of the older person; ageism; and structural barriers. These areas were felt to influence success of current prospects for future programs for older people.

DISCUSSION

Further communication, collaboration and integration appears essential to realise the potential that general practice offers to programs for older people. Issues from the forum are discussed in relation to relevant National General Practice Strategy Review and the changes introduced into the Medical Benefits Schedule in November 1999. Consideration of these themes will aid future divisional programs for older people.

The extended Segmüller flap

A modification of the homodigital lateral V-Y advancement flaps described by Segmüller in 1976 for the treatment of fingertip injuries is described. The extended flap used in this series makes this flap more versatile in the treatment of injuries with considerable soft-tissue loss from the volar aspect of the fingertip. The Segmüller flap technique, its applications, and the results of 100 flaps are reported and discussed.

Out-of-hospital cardiac arrest

Out-of-hospital cardiac arrest (OHCA), with its high fatality rate, is a significant public health issue. The aetiology of OHCA is reviewed, and management strategies are discussed, including the "chain of survival", the Utstein method of data collection, and recent developments in advanced cardiac life support emphasising defibrillation.

Functionally different GPI proteins are organized in different domains on the neuronal surface

We have investigated the organization, on the plasma membrane and in detergent-insoluble membrane vesicles, of two neuronal glycosylphosphatidylinositol-anchored (GPI) proteins: Thy-1, a negative regulator of transmembrane signalling; and prion protein, whose rapid endocytosis and Cu(2+) binding suggest that it functions in metal ion uptake. Prion protein occurred on the neuronal surface at high density in domains, located primarily at the cell body, which were relatively soluble in detergent. Thy-1, although much more abundantly expressed on neurons, occurred at lower density over much of the surface of neurites (and in lower abundance at the cell body) in domains that were highly resistant to detergent solubilization. Detergent-insoluble membrane vesicles contained Thy-1 at a density similar to that on the neuronal surface. Vesicles containing each protein could be separated by immunoaffinity isolation; lectin binding showed that they were enriched in different glycoproteins. Our results demonstrate a structural diversity of the domains occupied by functionally different GPI proteins.

Efficacy of intramammary immunization with an Escherichia coli J5 bacterin

Intramammary immunization was investigated as a procedure to reduce the clinical signs of coliform mastitis. Twenty-four cows were equally distributed to the following Escherichia coli J5 immunization schedules: 1) Subcutaneous injection 14 d prior to the end of lactation, intramammary immunization 7 d after drying off, and subcutaneous injection 30 d into the dry period; 2) subcutaneous injections at drying off, at 30 d into the dry period, and within 12 h after calving; and 3) unimmunized controls. Intramammary immunizations were the infusion of vaccine via the teat canal into each of the four mammary glands. Cows were challenged by infusion of E. coli 727 into one uninfected mammary quarter at approximately 30 d after calving. Intramammary immunization enhanced antibody titers against E. coli J5 and E. coli 727 compared with subcutaneous immunization. Immunoglobulin G titers against E. coli J5 and E. coli 727 in whey were greater at the time of challenge and 7 d after challenge for cows that received the intramammary immunization than for cows immunized by only subcutaneous injections. Serum IgG titers against E. coli 727 were enhanced at 7 d after challenge for cows receiving intramammary immunizations compared with conventionally immunized cows. Serum IgM titers against E. coli 727 were higher at calving for cows receiving intramammary immunization compared with conventionally immunized cows. Immunization schedule had minimal effect on systemic and local signs of clinical mastitis following challenge.

Orthopaedic residency training: a survey of the graduates' perspective

STUDY DESIGN

A survey of residency graduates.

OBJECTIVES

To establish a profile of the typical graduate and to determine the value and influence of residency training on professional development, particularly on clinical expertise.

BACKGROUND

Physical therapists are involved in direct access in some states as a result of health care reform. There is increasing interest within the physical therapy profession in evaluating residency education as an avenue for providing physical therapists with the advanced skills to meet the changing nature of providing care.

METHODS AND MEASURES

A questionnaire was sent to 98 graduates of a year long advanced orthopaedic manual therapy residency program. A response rate of 94.9% was obtained.

RESULTS

Influence of residency training on clinical skills and expertise received high ("major positive") ratings on the abilities to logically reason (94%), thoroughly examine (95%), treat effectively (84%) and efficiently (79%), and to "diagnose" (85%). Graduates spend 23% of their time teaching in some manner. Autonomy of decision making was the primary factor (43%) in determining place of work.

CONCLUSIONS

The results of this survey suggest that residency education assists physical therapists to refine and expand their clinical knowledge and skills that are important for health care roles requiring increasing autonomy of practice, such as primary care. Our questionnaire may also serve as a template for the measurement of outcome in clinical physical therapy residency programs.

Making sense of problem-based learning: the perceptions and experiences of undergraduate nursing students

This paper reports the findings of one stage of an ongoing project to evaluate a problem-based learning (PBL) curriculum. Focusing on the students themselves, the ethnographic study explored how undergraduate nursing students (n=17) managed and made sense of a PBL programme. Fieldwork and ethnographic interviews revealed the students' perceptions of the purpose of PBL and further issues that were of concern were identified and labelled the uncertainty of functioning without a clearly delineated educational structure, perceptions of knowledge acquisition, understanding of group interaction processes, and the role of the facilitator. These findings and the implications that arise as a result are discussed.

Antigenic homology of the inducible ferric citrate receptor (FecA) of coliform bacteria isolated from herds with naturally occurring bovine intramammary infections

Expression of ferric citrate receptor FecA by Escherichia coli and Klebsiella pneumoniae isolated from bovine mastitis was investigated. Transformant E. coli UT5600/pSV66, which produces large quantities of FecA in the presence of citrate, was constructed. The FecA of E. coli UT5600/pSV66 was purified by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and used to prepare polyclonal antiserum in rabbits. All coliform isolates of E. coli (n = 18) and K. pneumoniae (n = 17) from naturally occurring bovine intramammary infections in five herds induced iron-regulated outer membrane proteins when grown in Trypticase soy broth containing 200 microM alpha-alpha'-dipyridyl and 1 mM citrate. Polyclonal antiserum against FecA was used in conjunction with an immunoblot technique to determine the degree of antigenic homology of FecA among isolates. In the presence of citrate, each isolate expressed FecA that reacted with the anti-FecA polyclonal antiserum. The molecular mass of FecA ( approximately 80.5 kDa) was also highly conserved among isolates. Therefore, the ferric citrate iron transport may be induced in coliform bacteria and utilized to acquire iron in milk for survival and growth. The FecA is an attractive vaccine component for controlling coliform mastitis during the lactation period.

Developmental neuroplasticity: roles in early life seizures and chronic epilepsy

Both clinical and experimental studies suggest that the immature nervous system is unusually susceptible to seizures during critical periods in postnatal life. A late onset of gamma-aminobutyric acid (GABA)-mediated synaptic inhibition could conceivably play a contributing role in this phenomenon. Numerous studies have shown that neural systems that use GABA in the neonatal brain are different than those of adulthood. GABA is an excitatory neurotransmitter that likely plays a neurotrophic role in neuronal differentiation. Other reports suggest that unique, possibly transient, GABAergic interneuron populations exist in the embryonic and neonatal nervous system. At these early times in development, the immature nervous system is remarkably resistant to seizure generation. However, as the hippocampus and neocortex enter the critical period of enhanced seizure susceptibility, inhibitory GABA systems mature rapidly. At this time, blockade of GABA type A (GABAA) receptors produce unusually severe seizure discharges. In hippocampus, concurrent exuberant outgrowth of recurrent excitatory axon collaterals and synapses appear to play a role in the generation of these seizures. As the hippocampus matures, these axons are morphologically remodeled and nearly 50% of branches within arbors are pruned. This pruning of axon branches corresponds in time with the decrease in seizure susceptibility that characterizes adulthood. Developmental remodeling of neuronal connectivity is a common feature of most areas of the central nervous system. Results from an audiogenic seizure model of early onset epilepsy suggest that prevention of axon arbor remodeling by transient sensory deprivation can lead to a permanent overinnervation of target nuclei and chronic seizure susceptibility. Early life seizures may have a similar effect. Recent results in one model have shown that repeated seizures induced by intrahippocampal injections of tetanus toxin during a critical period results in a chronic epilepsy. Future studies should attempt to determine if the synchronized discharging of early-life seizures prevents the remodeling of neuronal connectivity that normally takes place during postnatal development and results in an overinnervated and chronically hyperexcitable hippocampus.

Molecular diversity in Bacillus anthracis

Molecular typing of Bacillus anthracis has been extremely difficult due to the lack of polymorphic DNA markers. We have identified nine novel variable number tandemly repeated loci from previously known amplified fragment length polymorphism markers or from the DNA sequence. In combination with the previously known vrrA locus, these markers provide discrimination power to genetically characterize B. anthracis isolates. The variable number tandem repeat (VNTR) loci are found in both gene coding (genic) and non-coding (non-genic) regions. The genic differences are 'in frame' and result in additions or deletion of amino acids to the predicted proteins. Due the rarity of molecular differences, the VNTR changes represent a significant portion of the genetic variation found within B. anthracis. This variation could represent an important adaptive mechanism. Marker similarity and differences among diverse isolates have identified seven major diversity groups that may represent the only world-wide B. anthracis clones. The lineages reconstructed using these data may reflect the dispersal and evolution of this pathogen.

Bacterial counts associated with sawdust and recycled manure bedding treated with commercial conditioners

Bacteria counts associated with untreated organic bedding materials were compared with those of bedding treated with either an alkaline commercial bedding conditioner, acidic commercial bedding conditioner, or hydrated lime. Bedding materials were recycled manure and kiln-dried sawdust. The effects of bedding treatments on bacteria counts differed between bedding types. Each of the bedding treatments significantly reduced bacteria in recycled manure prior to use. The alkaline conditioner and hydrated lime effectively inhibited bacteria in recycled manure for 1 d. Bedding counts and teat swabs of cows housed on recycled manure treated with the alkaline conditioner were reduced on d 2. The use of the acid conditioner in recycled manure had little effect on bacteria in bedding. Sawdust differed from recycled manure in that bacteria in untreated sawdust prior to use were minimal, and populations increased rapidly during the first 2 d after use as bedding. The acid conditioner had a bacteriostatic effect in sawdust, evident by the reduction of bacteria on d 2. The alkaline conditioner and hydrated lime did not alter bacteria counts in sawdust compared with untreated sawdust. Antibacterial activity of each conditioner deteriorated between d 2 and d 6 in both beddings. The antibacterial activities of conditioners were related to the pH of bedding materials. The use of commercial bedding conditioners initially reduced bacterial counts; however, the antibacterial effects had diminished between d 2 and 6 after use in bedding.

Meso-scale ecology of anthrax in southern Africa: a pilot study of diversity and clustering

It has only recently been possible to detect sufficient genetic diversity among anthrax isolates to allow genotype grouping (Keim et al. 1997). Early results of such grouping suggest that the southern African subcontinent may be the geographical origin of Bacillus anthracis. This report describes a pilot investigation of the genetic diversity of a study group of isolates from the Kruger National Park, South Africa, and efforts to detect spatio-temporal clustering within the study group. This study has also served as further validation for the newly developed Multi-Locus VNTR Analysis (MLVA), designed to simplify genotyping of B. anthracis isolates. The results reveal a diverse range of genotypes within the park allied with three genotype reference groups, and show that the MLVA procedure is robust for rapid analysis of B. anthracis genotypes. We also observed multiple genotype groups within epidemics and between geographically and temporally close epidemic episodes. This is in contrast to earlier characterizations of anthrax epidemics. The result of a Mantel test for time-space clustering indicates clustering of the anthrax isolates selected for the study.

Simple home program for frozen shoulder to improve patients' assessment of shoulder function and health status

BACKGROUND

The purpose of this investigation was to test the hypothesis that a simple home program can improve the self-assessed shoulder function and health status of a group of patients with frozen shoulders.

METHODS

A case series using a one-group pretest, posttest design analyzing 41 patients from a single orthopedic practice who had a frozen shoulder were included in this study. The patients completed the Simple Shoulder Test (SST) and the Medical Outcomes Study Short-Form Health Survey (SF-36) questionnaire at the time of initial consultation, had treatment consisting of education regarding frozen shoulder and home stretching instructions, and were asked to complete the same questionnaires mailed every 6 months. Initial results were compared with previously published control values to establish level of impairment, and follow-up results were compared with the initial results to determine the extent of improvement.

RESULTS

Patients initially had serious deficits in the 12 shoulder functions inventoried by the SST and were also compromised in their general health status as reflected by the SF-36 scores. At follow-up, 4 of 10 SST functions were improved (P < 0.001). The SF-36 health status scores of physical function, comfort, and physical role function were also improved (P < 0.001).

CONCLUSION

These data suggest that this home program for frozen shoulder can lead to improved self-assessed shoulder function and health status in patients similar to those in the study population.

Self-assessment questionnaires document substantial variability in the clinical expression of rotator cuff tears

The goal of this investigation was to document the variability in the clinical expression of full-thickness rotator cuff tears with practical and standardized patient self-assessment tools. One-hundred twenty-three consecutive patients with full-thickness cuff tears diagnosed by standard cuff-imaging methods (sonography, arthrography, or magnetic resonance imagery) assessed their own shoulder function and health status with the Simple Shoulder Test and the Short Form 36, respectively. As a group, these patients were substantially compromised in their ability to perform the functions of the Simple Shoulder Test and in the Short Form 36 scales of physical role, physical function, and comfort. As individuals, however, their self-assessments varied widely. The standard deviations were often greater than 50% of the mean and the range of responses often covered the entire scale from the minimum possible score to the maximum possible score. These results show the importance of documenting the clinical expression of cuff tears in patients at initial evaluation and when treatment is being considered. The results also show the practicality of standardized self-assessment questionnaires in such documentation.