New germline mutations in the hypervariable minisatellite CEB1 in the parents of children with leukaemia

Gardner and co-workers advanced the hypothesis that the Seascale leukaemia cluster could have been caused by new mutations in germ cells, induced by paternal preconceptional irradiation (PPI) exposure at the Sellafield nuclear installation. Since evidence has shown that PPI can increase the de novo germline mutation rate in hypervariable minisatellite loci, we investigated the hypothesis that sporadic childhood leukaemia might be associated with an increased parental germline minisatellite mutation rate. To test this hypothesis, we compared de novo germline mutation rates in the hypervariable minisatellite locus, CEB1, in family trios (both parents and their child) of children with leukaemia (n=135) compared with unaffected control families (n=124). The majority of case and control germline mutations were paternal (94%); the mean paternal germline mutation rates of children with leukaemia (0.083) and control children (0.156) were not significantly different (odds ratio, 95% confidence interval: 0.50, 0.23–1.08; P=0.11). There were no significant differences in case and control parental allele sizes, case and control germline mutation progenitor allele sizes (2.74 vs 2.54 kb; P=0.56), case and control mutant allele sizes (2.71 vs 2.67 kb; P=0.90), mutant allele size changes (0.13 vs 0.26 kb; P=0.10), or mutational spectra. Within the limitation of the number of families available for study, we conclude that childhood leukaemia is unlikely to be associated with increased germline minisatellite instability.

A randomised control trial comparing lifestyle groups, individual counselling and written information in the management of weight and health outcomes over 12 months

OBJECTIVE

To investigate the effect of an 8-week group-based cognitive behaviour therapy lifestyle intervention with monthly follow-up to 6 months and further follow up at 12 months on change in weight and other weight-related variables, change in physical activity and change in health and well being compared to individualised dietetic treatment or giving an information booklet only (BO).

DESIGN

A randomised controlled trial of two intervention groups, a group-based cognitive behaviour therapy lifestyle intervention, Fat Booters Incorporated--(FBI) and individualised dietetic treatment (IDT) and control group receiving an information booklet only (BO). The intervention groups involved weekly contact for 8 weeks with monthly follow-up to 6 months and further follow-up at 12 months, conducted in real practice setting.

SUBJECTS

A total of 176 adults with body mass index (BMI)>27 kg/m2, mean (+/-s.d.) age 48+/-13 years, mean BMI 34+/-5.5 kg/m2.

MAIN OUTCOME MEASURES

Weight, percent body fat, waist circumference, physical activity, health status, self-efficacy and satisfaction with life were measured at baseline, 3, 6 and 12 months.

RESULTS

A statistically significant difference between groups was observed for weight change over time (P=0.05). The change in weight (mean+/-s.e.) for the FBI group was significantly greater than the BO group at 3 and 12 months (-2.8+/-0.7 compared to -1.0+/-0.6 kg, P<0.05 and -2.9+/-0.9 compared to +0.5+/-0.9 kg, P<0.005, respectively). Change in weight in the IDT group did not differ from the FBI group at any time point. For all groups, waist circumference was significantly less than baseline at all time points (P<0.001). Significant differences in self-efficacy were observed over time (P=0.02), with both intervention groups having greater self-efficacy than the BO group. Significant drop-outs occurred over time for all three groups.

CONCLUSIONS

A cognitive behaviour-based lifestyle intervention was more effective than providing an information booklet alone and as effective as intensive individualised dietetic intervention in weight loss and improvements in self-efficacy.

Effect of clonidine pre-medication on propofol requirements during lower extremity vascular surgery: a randomized controlled trial

BACKGROUND

Pre-medication with clonidine reduces the requirement for volatile agents during general anaesthesia. This may also be true for anaesthesia with propofol, but the amount of dose reduction has not been measured. Because clonidine also affects cardiac output and thus regional blood flow it could alter the pharmacokinetics of propofol. This randomized, double-blind placebo-controlled trial aimed to study the effect of clonidine pre-medication on dose requirement for propofol during lower extremity vascular surgery using the bispectral index (BIS) as a measure of anaesthetic depth.

METHODS

After oral pre-medication with either clonidine 3 microg kg(-1) or placebo, 39 subjects had lower limb vascular surgery using propofol infusion for anaesthesia. Anaesthetic depth was adjusted to a BIS of 45. Predicted plasma propofol concentrations were noted every 30 min from a target-controlled propofol infusion pump and arterial samples were taken at the same time for propofol measurements.

RESULTS

Patients in both groups were anaesthetized to similar depths of anaesthesia as indicated by BIS readings (P=0.44). The groups had comparable mean (95% CI) arterial concentrations of propofol, 4.8 (3.5-6.1) microg ml(-1) in the patients given clonidine, and 4.6 (3.4-5.7) microg ml(-1) in the patients given placebo (P=0.81). However, the average plasma concentration predicted by the target-controlled infusion was less in the clonidine group [3.2 (2.9-3.5)] than in the group given placebo [3.6 (3.3-3.9)] microg ml(-1) (P<0.05).

CONCLUSIONS

Pre-medication with clonidine reduces the requirement for propofol, which is a pharmacokinetic effect and not a pharmacodynamic central sedative effect.

Does the provision of pre-prepared morphine solution alter the administration of opioids to patients in the recovery room?

The provision of immediate postoperative analgesia using titrated intravenous opioid is widespread. Protocols requiring two nurses to sign out, check and draw up opioid solutions are time-consuming and might act as a bar to the prompt provision of analgesia. One hundred and five patients were randomly assigned to one of three groups. Prepared morphine solution 10 mg (Group Ten) or 5 mg (Group Five) or no syringe (Group Zero) accompanied the patient to the post anaesthesia care unit. Nursing staffs were unaware of the trial. The likelihood of receiving morphine was actually higher in Group Zero than in Groups Five and Ten but not significantly different (relative risk 1.4, 95% confidence intervals 0.8-2.4). The dose of morphine administered was not significantly different between the groups. Provision of pre-prepared opioid solution did not increase either the frequency of morphine administration or the dose in this study.

Cu, Cr and As distribution in soils adjacent to pressure-treated decks, fences and poles

Chromated copper arsenate (CCA)-treated wood has been widely used in the Southeastern United States to protect wood products from microbial and fungal decay. The aims of this study were to (1). determine the distribution of arsenic (As), chromium (Cr), and copper (Cu), in soils surrounding CCA-treated wood structures such as decks, fences and poles; and (2). evaluate the impacts of these structures on As, Cr and Cu loading of the soils. Profile and lateral soil samples were collected under CCA-treated decks and adjacent to poles and fences. The results showed elevation of As, Cr and Cu concentrations close to and under the structures, with mean As concentrations as high as 23 mg x kg(-1) close to utility poles compared with less than 3 mg x kg (-1) at distances of about 1.5 m away. Concentrations of As, Cr, and Cu decreased with depth in areas close to CCA-treated poles. However, these results were only apparent in relatively new structures. A combination of weathering and leaching with time may have reduced the impact in older poles. Increased concentrations of As, Cu and Cr were also observed close to CCA-treated decks and fences, with age showing a similar impact. These results are helpful for CCA-treated wood product users to determine the safe use of these structures.

Adding ketamine to morphine for patient-controlled analgesia after major abdominal surgery: a double-blinded, randomized controlled trial

In this double-blinded, randomized controlled trial we tested if the addition of ketamine to morphine for patient-controlled analgesia (PCA) resulted in improved analgesic efficacy and lower pain scores compared with morphine PCA alone after major abdominal surgery. Seventy-one patients were randomly allocated to receive either morphine 1 mg/mL (Group M) or morphine 1 mg/mL plus ketamine 1 mg/mL (Group MK) delivered via PCA after surgery. No other analgesics or regional blocks were permitted during the 48-h study period. Postoperatively there were no differences between the groups for subjective assessment of analgesic efficacy, pain scores at rest, and on movement, opioid consumption, or adverse events. Group MK patients performed worse in cognitive testing (P = 0.037). There was an increased risk of vivid dreaming in patients who received ketamine (relative risk = 1.8, 95% confidence interval 0.78-4.3). We conclude that small-dose ketamine combined with PCA morphine provides no benefit to patients undergoing major abdominal surgery.

IMPLICATIONS

We performed a randomized, controlled trial comparing the use of ketamine and morphine with morphine alone to relieve pain after major abdominal surgery.Ketamine did not improve pain relief and merely increased side effects.

Persistence of a distinct Corynebacterium diphtheriae clonal group within two communities in the United States and Canada where diphtheria is endemic

Molecular characterization of 53 U.S. and Canadian Corynebacterium diphtheriae isolates by multilocus enzyme electrophoresis, ribotyping, and random amplified polymorphic DNA showed that strains with distinct molecular subtypes have persisted in the United States and Canada for at least 25 years. These strains are endemic rather than imported from countries with current endemic or epidemic diphtheria.

Rapid identification of Corynebacterium diphtheriae clonal group associated with diphtheria epidemic, Russian Federation

We used 199 Corynebacterium diphtheriae isolated from 1995 to 1997 in Russia to evaluate the ability of random amplified polymorphic DNA (RAPD) to identify the unique clonal group that emerged there in 1990. Our data show that RAPD can reliably, reproducibly, and rapidly screen a large number of strains to identify the epidemic clonal group.

Measurement of complex surface deformation by high-speed dynamic phase-stepped digital speckle pattern interferometry

We describe a high-speed digital speckle pattern interferometer incorporating a line-scan camera and a waveguide phase modulator for the measurement of complex deformation (vibration phase and amplitude) at audio acoustic frequencies. Experimental data show continuous phase-stepped recovery of out-of-plane surface deformation in one dimension, obtained at 100 kHz with 2pi/20-rad (0.02-mum) displacement resolution, for surface velocities of 3.2 mm s>(-1) .

Identification and cellular localisation of voltage-operated calcium channels in immature rat testis

Sertoli cells regulate the spermatogenic process mainly through the secretion of a complex fluid into the lumen of the seminiferous tubules behind the blood-testis barrier, containing many of the essential proteins necessary for maintenance and maturation of male germ cells. Thus, the study of Sertoli cell secretory processes is strictly correlated with the understanding of the regulatory mechanisms of spermatogenesis. In this work the authors have explored the voltage-sensitive calcium channel variety in the immature rat testis, their localisation and distribution within the seminiferous epithelium and peritubular and interstitial tissues as well as the possible role in the control of Sertoli cell secretion. The results reported in this paper, obtained by in situ hybridisation, immunohistology of rat testicular sections and Western blot analysis of Sertoli cell plasma membranes, show that mammalian Sertoli cells express mRNA encoding for several voltage-operated calcium channel subunits and express such proteins on their surface. Experiments performed on Sertoli cell monolayers cultured in the presence of specific toxins indicate that both N and P/Q-type Ca(2+) channels are involved in the regulation of protein secretion.

The pain visual analog scale: is it linear or nonlinear?

The visual analog scale (VAS) is a tool widely used to measure pain, yet controversy surrounds whether the VAS score is ratio or ordinal data. We studied 52 postoperative patients and measured their pain intensity using the VAS. We then asked them to consider different amounts of pain (conceptually twice as much and then half as much) and asked them to repeat their VAS rating after each consideration (VAS2 and VAS3, respectively). Patients with unrelieved pain had their pain treated with IV fentanyl and were then asked to rate their pain intensity when they considered they had half as much pain. We compared the baseline VAS (VAS1) with VAS2 and VAS3. The mean (95% confidence interval) for VAS2:1 was 2.12 (1.81-2.43) and VAS3:1 was 0.45 (0.38-0.52). We conclude that the VAS is linear for mild-to-moderate pain, and the VAS score can be treated as ratio data.

IMPLICATIONS

A change in the visual analog scale score represents a relative change in the magnitude of pain sensation. Use of the VAS in comparative analgesic trials can now meaningfully quantify differences in potency and efficacy.

Epidemic serogroup B meningococcal disease in Oregon: the evolving epidemiology of the ET-5 strain

CONTEXT

In 1993, Oregon's incidence of serogroup B meningococcal disease began to rise because of a highly clonal group of strains designated enzyme type 5 (ET-5), the first such increase observed in the United States.

OBJECTIVE

To evaluate the impact that the ET-5 strain has had on the epidemiology of meningococcal disease in Oregon.

DESIGN AND SETTING

Epidemiologic analysis of surveillance data on Oregon meningococcal disease cases from 1987 through 1996 and multilocus enzyme electrophoresis typing of serogroup B isolates from June 1993 through April 1995 and from April through June 1996.

PATIENTS

A total of 836 persons with invasive meningococcal disease.

MAIN OUTCOME MEASURES

Disease frequency and clonality of strains.

RESULTS

Serogroup B disease incidence rates more than doubled from the preepidemic period in 1987-1992 (1.0 case per 100000 population) to the recent epidemic period in 1995-1996 (2.2 cases per 100000). The age-specific incidence rate of serogroup B disease among those 15 through 19 years old increased 13-fold between the preepidemic period (0.5 case per 100000) and 1995-1996 (6.4 cases per 100000). However, the proportion of cases with meningococcemia and the case-fatality rate did not change. Of 99 Neisseria meningitidis isolates obtained from 1993-1995, 88 (89%) belonged to the ET-5 complex. Of these, 69 (78%) were a single clone, designated 301. Of 20 serogroup B isolates from 1996, 18 (90%) belonged to the ET-5 complex; 17 (94%) were the 301 clone.

CONCLUSION

Serogroup B meningococcal disease incidence continues at high levels in Oregon with increasing predominance of the ET-5 clonal strains.

Use of molecular subtyping to document long-term persistence of Corynebacterium diphtheriae in South Dakota

Enhanced surveillance of patients with upper respiratory symptoms in a Northern Plains community revealed that approximately 4% of them were infected by toxigenic Corynebacterium diphtheriae of both mitis and gravis biotypes, showing that the organism is still circulating in the United States. Toxigenic C. diphtheriae was isolated from five members of four households. Four molecular subtyping methods-ribotyping, multilocus enzyme electrophoresis (MEE), random amplified polymorphic DNA (RAPD), and single-strand conformation polymorphism-were used to molecularly characterize these strains and compare them to 17 archival South Dakota strains dating back to 1973 through 1983 and to 5 isolates collected from residents of diverse regions of the United States. Ribotyping and RAPD clearly demonstrated the household transmission of isolates and provided precise information on the circulation of several distinct strains within three households. By MEE, most recent and archival South Dakota strains were identified as closely related and clustered within the newly identified ET (electrophoretic type) 215 complex. Furthermore, three recent South Dakota isolates and eight archival South Dakota isolates were indistinguishable by both ribotyping and RAPD. All of these molecular methods showed that recent South Dakota isolates and archival South Dakota isolates were more closely related to each other than to the C. diphtheriae strains isolated in other parts of the United States or worldwide. The data also supported the improbability of importation of C. diphtheriae into this area and rather strongly suggest the long-term persistence of the organism in this region.

Characterization and partial purification of CD34+ progenitor cell ecto-phosphatidic acid phosphohydrolase

Phosphatidic acid and its hydrolysis product, diacylglycerol, play potentially vital roles as extracellular messengers in numerous cellular systems and may play a key role in regulating hematopoiesis. In this study, we describe an ecto-phosphatidic acid phosphohydrolase that potentially regulates cellular responses to phosphatidic acid on bone marrow derived human hematopoietic progenitors. We partially purified hematopoietic progenitor ecto-PAPase using a novel in-gel phosphatase assay and then characterized the enzyme on phenotypically defined subpopulations of hematopoietic CD34+ progenitors isolated by flow cytometry. The most pronounced PAPase activity was confined to uncommitted CD34+/CD38+ hematopoietic progenitors, which lacked the expression of other lineage-associated antigens. We conclude that hematopoietic progenitor cells at various stages of maturation possess a potent ecto-PAPase, an enzyme well positioned to regulate progenitor cell growth and differentiation induced by phosphatidic acid and related lipids.

Confocal, two-photon laser-induced fluorescence technique for the detection of nitric oxide

We describe a confocal two-photon laser-induced fluorescence scheme for the detection of gaseous NO. Excitation from a simple YAG-pumped Coumarin 450 dye system near 452.6 nm was used to promote the two-photon NO(A (2)?(+), nu? = 0 ? X (2)?, nu? = 0) transition in the gamma(0, 0) band. Subsequent fluorescence detection in the range 200-300 nm permitted almost total rejection of elastic and geometric scatter of laser radiation for excellent signal/noise ratio characteristics. The goal of the research was to apply NO fluorescence to a relatively realistic limited optical access combustion environment. A confocal optical arrangement was demonstrated for single-point measurements of NO concentration in gas samples and in atmospheric-pressure flames. The technique is suitable for applications that offer only a single direction for optical access and when significant elastic scatter is present.

Tuberculosis case detection in a state prison system

OBJECTIVE

This study was designed to describe the epidemiology of tuberculosis ((TB) among inmates in the Georgia state prison system; to evaluate the effectiveness of the TB case detection methods used; to evaluate the use of contact tracing for inmate TB cases; and to determine rates of completion of therapy.

METHODS

Using a standardized form, the authors abstracted data from reports to the Centers for Disease Control and Prevention, prison hospital medical charts, and county health department records for all patients with TB treated in the Georgia Department of Corrections prison system from 1991 through 1995.

RESULTS

A total of 142 cases of tuberculosis were treated in the prison during five-year period. Approximately two-thirds were detected by active case finding,either at the county jail prior to transfer to the prison system (31%) or at the prison intake evaluation (37%). Routine screening procedures at entry, following Centers for Disease Control and Prevention guidelines, had a sensitivity of 96%. Contact investigations were carried out in county jails or in the community for only 25% of cases detected at entry to prison. For those released from prison still on treatment, 38% were lost to follow-up before completion of therapy.

CONCLUSIONS

The Georgia prison system is doing an effective job of TB case detection and treatment among incarcerated inmates. Closer cooperation between the prison system and local health departments is needed to improve contact tracing and completion of therapy for this high risk population. Some cases detected at entry to prison appear to have been missed in the county jails

Molecular epidemiology of sporadic (endemic) serogroup C meningococcal disease

Understanding the basis of sporadic (endemic) meningococcal disease may be critical to prevention of meningococcal epidemic outbreaks and to understanding fluctuations in incidence. Active, prospective, population-based surveillance and molecular epidemiologic techniques were used to study sporadic serogroup C meningococcal disease in a population of 2.34 million persons (Atlanta area). During 1988-1994, in which no outbreaks or case clusters were reported, 71 patients developed sporadic serogroup C meningococcal disease (annual incidence, 0.51/100,000). Eighty-three percent of patients were >2 years old. By multilocus enzyme electrophoresis, pulsed-field gel electrophoresis, and serotyping, 84% (52/62) of the isolates available for study were identical or closely related members of the electrophoretic type 37 (ET 37) complex responsible for multiple serogroup C outbreaks in the United States in the 1990s. Sporadic disease caused by 9 clonal strains occurred over periods up to 4 years and accounted for 45% (28/62) of cases. Sporadic serogroup C meningococcal disease was most often due to a limited number of related strains that appear to slowly circulate in the population.

Topographic associations between DNA fragmentation and Alzheimer's disease neuropathology in the hippocampus

To identify whether the process of apoptosis bears a topographic relationship to selected aspects of Alzheimer's disease (AD) pathology, we used an in situ nick translation method (TUNEL) to map DNA fragmentation in hippocampal sections immunostained for abnormally phosphorylated tau, which exists in the neurofibrillary tangles (NFTs) and in the dystrophic neurites associated with senile plaques. To ascertain associations of DNA fragmentation with glia, TUNEL was combined with immunohistochemistry for the astrocyte marker, glial fibrillary acidic protein (GFAP), or the microglial antigen OX-42. Consistent with previous reports, the incidence of putative DNA fragmentation detected by TUNEL was much higher in the AD brain, compared to non-demented subjects. While most TUNEL-positive cells did not exhibit any systematic topographic relationship to senile plaques, which were visualized by immunostain of abnormally phosphorylated tau for dystrophic neurites, DNA fragmentation was found frequently within cells containing NFTs. In hippocampal sections prepared to visualize glia, DNA fragmentation was not observed in GFAP-positive astrocytes, but some OX-42-positive microglia exhibited TUNEL signals. Other TUNEL-positive cells were found frequently in proximity to glia. The data suggest that cells compromised by the deposition of NFTs are prone to initiate the process of apoptosis. Furthermore, some glial populations appear to be apoptotic in the AD brain.

The value of simulations in the management education of nurses: students' perceptions

This paper examines the use of simulations in the education of student nurses as part of their preparation for management responsibility. A review of the literature indicates that there is little published work on this topic and that those evaluations that have been reported invariably occur at the end of the exercise, thus giving an incomplete picture of the simulation. The nature and format of the simulation, used with 128 students undertaking a pre-registration/diploma in higher education course, is described. Results from student evaluations immediately following the exercise and after 13 weeks of clinical experience are presented. The findings indicate that this is a realistic and enjoyable way of learning which adequately prepares students for management experience in subsequent clinical allocations. Issues concerned with internal and external validity of simulations and areas for further research are explored.

Long-term survival in advanced chronic myelogenous leukemia following bone marrow transplantation from haploidentical related donors

From 1987 to 1991, 26 patients with CML and a median age of 31 years received allogeneic BMT from a partially mismatched related donor (PMRD) who shared at least one haplotype with the recipient. Nine patients were in accelerated phase (AP), and 11 patients were in blast crisis (BC) at the time of BMT. Patients were mismatched either in graft-versus-host or host-versus-graft directions for one antigen in 3 patients, two antigens in 14 patients, and three antigens in 9 patients. All patients were prepared with a regimen consisting of total body irradiation, etoposide, cytosine arabinoside, cyclophosphamide and methylprednisolone. All marrows were treated ex vivo with T10B91.A-31, a monoclonal antibody directed toward the alpha beta heterodimer of the CD3 receptor, and rabbit complement. Additional GVHD prophylaxis included either the anti-CD5 immunoconjugate XomaZyme-H65, cyclosporine, or both in combination with methylprednisolone. Eight patients did not have sustained engraftment. The 100-day survival was 42%. The incidence of > or = grade II acute GVHD was 29%. The incidence of chronic GVHD was 50% and was limited in all cases. The median survival at 4 years for all 26 patients was 27%. Seven patients (CP 1, AP 3, BC 3) remain in hematologic remission 1297-2241+ days after transplantation. AlloBMT from a PMRD may be considered for patients with advanced CML who lack a matched sibling or unrelated donor.

The utilization and evaluation of a simulation game in pre-registration nurse education

The employment of simulations and games has been widely recommended for use in nurse education but there are few reports of their introduction or evaluation. This paper describes the use and evaluation of a simulation game which prepares students for a management module in an English National Board pilot scheme course. Evaluation took place by using a questionnaire completed by 528 students and by participant observation by the facilitators. The evaluation indicates that a simulation game is an appropriate way of preparing students for practice and that it provides a realistic and safe environment for enjoyable and meaningful learning to take place.

Axonal interactions regulate Schwann cell apoptosis in developing peripheral nerve: neuregulin receptors and the role of neuregulins

Programmed cell death during development resulting from the lack of appropriate survival factors has been demonstrated in both neurons and oligodendrocytes and occurs mostly in the form of apoptosis. We now demonstrate that Schwann cells in the rat sciatic nerve undergo apoptosis during early postnatal development and that the amount of apoptosis is markedly increased by axotomy. The apoptotic Schwann cells express the low-affinity nerve growth factor receptor but not myelin-related proteins, indicating that they are in the premyelinating state. Apoptosis resulting from normal development or from axotomy can be inhibited markedly by exogenous neuregulin. Consistent with this, the neuregulin receptor components erbB2 and erbB3 are expressed and phosphorylated in developing sciatic nerve. These data suggest that Schwann cell number in developing peripheral nerve is regulated by apoptosis through competition for axonally derived neuregulin.

Forage quality of kikuyu (Pennisetum clandestinum): the effect of time of defoliation and nitrogen fertiliser application and in comparison with perennial ryegrass (Lolium perenne)

This study, conducted on the north coast of New South Wales, determined the optimal time to defoliate kikuyu (Pennisetum clandestinum Hochst ex chiov.) in terms of pasture quality in relation to the number of leaves per tiller. It also compared the quality of well-managed kikuyu grass and ryegrass (Lolium perenne L.) pasture to determine the nutrients in kikuyu likely to limit milk production. The crude protein (CP), P, and K concentrations of individual leaves declined; Ca and Mg increased; and Na levels remained constant with increasing age. These changes in individual leaves were reflected in the quality of kikuyu available above the 5-cm stubble height. The proportion of green leaf available above the 5-cm stubble height declined whilst the proportion of stem and dead material increased markedly after 4.5 leaves per tiller had regrown. These changes were reflected in a substantial decline in organic matter digestibility (OMD) and CP of herbage. Between 0900 and 1500 hours, water-soluble carbohydrate (WSC) levels in kikuyu above the 5-cm stubble height increased at a rate of 5 g/kg dry matter (DM) per hour, reaching maximum levels during the mid afternoon. Kikuyu fertilised at a high rate of N fertiliser contained significantly higher nitrate levels than that receiving moderate levels (3.12 v. 0. 67 g/kg DM, respectively). There was a linear increase in the levels of nitrate as the CP of forage exceeded 230 g/kg DM. Kikuyu and ryegrass samples plucked to simulate forage consumed by milking cows were obtained in the midst of the growing season for each species. Kikuyu had a lower OMD than ryegrass (733 v. 842 g/kg DM) but contained higher levels of neutral detergent fibre (600 v. 400 g/kg DM). High levels of CP and low content of WSC in kikuyu compared with ryegrass resulted in a much lower ratio WSC: CP (0.09 v. 0.36, respectively). Kikuyu contained 50% less Ca than ryegrass, much of which would be expected to be bound to oxalates and thus unavailable to grazing stock. The concentration of Na in kikuyu was extremely low compared with ryegrass (0.15 v. 3.67 g/kg DM, respectively). The most desirable stage of regrowth of kikuyu on which to graze lactating dairy cows, in terms of a compromise between forage quality and quantity, appears to be at 4.5 leaves/tiller. However, even at this stage, various innate nutrient deficiencies would appear to restrict milk production to 15-16 L milk/cow.day.

A comparison of three techniques to determine the herbage intake of dairy cows grazing kikuyu (Pennisetum clandestinum) pasture

Two studies were conducted to compare the precision of estimating kikuyu grass (Pennisetum clandestinum) intake by Friesian cows fed 0, 3 or 6 kg of cereal-based concentrate/cow.day, using a rising plate meter (RPM), standard energy requirements in reverse (RS) and plant wax alkanes as internal markers. Study 1 compared herbage intake estimates obtained using the RPM and RS techniques over a 45-day period. RS estimates were based on the metabolisable energy (ME) of ration components derived from in vitro organic matter digestibility (OMD) values. Pregrazing calibration equations for the RPM determined at 2-weekly intervals differed significantly (P<0.01) from postgrazing calibrations; consequently separate equations were used to determine pasture intake as the difference in pre- and post-grazing pasture mass. Estimates of total intake were lower using the RPM than the RS technique for the groups fed 0 kg (12.5 v. 14.8 kg dry matter (DM)/cow.day) and 3 kg (10.4 v. 12.9 kg DM/cow.day) of concentrate, and higher for those receiving 6 kg (10.5 v. 7.8 kg DM/cow.day). In study 2 (12 days duration), intakes derived using alkanes were compared with intakes estimated using the RS and RPM techniques. The C32/C33 alkane pair gave the closest estimate of herbage intake to that obtained using the RPM and RS techniques. Whole diet in vivo DM digestibility (DMD), determined by the alkane method, was not significantly different between the 3 groups (mean 70%), suggesting that digestibility of the kikuyu declined with increasing concentrate supplementation. The in vivo DMD of kikuyu alone (determined in the non-concentrate-supplemented cows) was considerably higher (69.5%) than the OMD determined in vitro (63.9%). By using in vivo rather than in vitro digestibilities for kikuyu in the RS calculations, the intake estimates were reduced by 17%, and for the 0 kg concentrate group, intake estimates aligned closely to predictions of the RPM and alkanes. Concentrates in the diet resulted in lower intake estimates using the RS technique compared with the RPM and alkane techniques. This was most evident at the 6 kg level of supplementation where RS predicted kikuyu intake to be 6.5 kg DM/cow.day using in vivo-derived DMD and this was substantially lower than either the RPM (12.4 kg DM/cow.day) or alkanes (9.2 kg DM/cow.day). The alkane technique provided a direct and precise method of measuring the intake of individual cows grazing tightly-managed kikuyu pasture. With the use of accurate animal production and feed quality parameters, the RS technique can provide sensible pasture intake estimates over an extended time period. The RPM technique is useful for obtaining herd estimates of pasture intake and for the determination of pasture parameters associated with intake.

Production responses of dairy cows grazing well-managed kikuyu (Pennisetum clandestinum) pastures to energy and protein supplementation

Three studies were conducted to examine the production response of Friesian cows grazing well-managed lukuyu (Pennisetum clandestinum) pasture to supplementation with a cereal grain concentrate, with and without the inclusion of formaldehyde-treated protein meal. Mean (¦ s.e.) levels of nutrients in the pasture (g/kg DM) on offer were: 205 ¦ 3 crude protein; 683 ¦ 7 in vitro organic matter digestibility; 239 ¦ 2 acid detergent fibre; 615 ¦ 8 neutral detergent fibre and 4.47 ¦ 0.16, 2.51 ¦ 0.06, 31.96 ¦ 0.98, 0.39 ¦ 0.03 and 3.18 ¦ 0.09 of calcium, phosphorus, potassium, sodium and magnesium, respectively. Study 1 was a 3-farmlet study conducted over 45 days (March-April 1993) involving cows 5-6 months into lactation, which compared 3 levels of concentrate feeding at 0 (R0), 3 (R3) or 6 (R6) kg crushed barley/cow.day. Study 2 was an 18-day extension of study 1 with animals in the seventh month of lactation. The concentrate fed was 72% barley and 24% formaldehyde-treated sunflower meal. Pasture intake of individual cows was determined using an alkane technique. Mean milk yields (L/cow. day) in study 1 were 14.2, 18.3 and 18.0, and in study 2 were 12.5, 18.5 and 17.4 for treatments R0, R3 and R6, respectively. Milk fat (3.77 v. 3.26%), but not milk protein, content of the Ro cows was significantly higher than R6 cows in study 1 only. In study 2, the apparent whole-diet digestibility remained constant as concentrate level rose, indicating a negative effect of concentrate fed on forage digestibility in the absence of buffers. Study 3 was a 3 x 4 factorial design plus a 'control' group (0.5 kg barley/cow.day used as a carrier for minerals) to examine the milk production response to 3 levels of concentrate feeding (3, 6 and 9 kg/cow.day) with 4 levels of formaldehyde-treated canola meal (FTCM; 0, 20, 40 and 60% of concentrate). Rations were iso-energetic within levels of concentrates fed. The control group had significantly lower milk production (17.2 L/cow.day), as well as milk protein (2.90%), plasma urea (PU) (5.90 mmol/L) and P-hydroxybutyrate (G-OHB) (0.525 mmo1L) than other treatment groups. The mean milk production response of 0.6 L milk/kg concentrate fed in study 3 at the 3 kg/day level of feeding was lower than observed in studies 1 and 2 (1.4 and 2.0 L/kg concentrate, respectively). The level of metabolisable energy in the concentrate in study 3 had a significant influence on milk production, milk fat and milk protein levels. Plasma glucose and G-OHB levels significantly increased with the incorporation of FTCM into the concentrate. Nonesterified fatty acid levels dropped significantly below levels of other treatments at the lowest level of inclusion of FTCM. PU levels generally increased in response to increasing metabolisable energy and inclusion of FTCM in the concentrate, with an interaction between them. Milk urea (MU) levels (mmol/L) showed a significant linear (P<0.001; r2 = 0.44) relationship to PU levels (mmol/L) as follows: MU = 0.167 + 0.272PU.

Biosorption of nickel in complex aqueous waste streams by cyanobacteria

A study was undertaken to determined if a suitable biosorbent could be found for removal of nickel at low concentrations (< 20 parts per million [ppm]) from a chemically complex wastewater effluent generated by electroplating operations. Algae and cyanobacteria were chosen as candidate biosorbent materials because they are easy to grow and they have the ability to withstand processing into biosorbent materials. Several species were screened for nickel-biosorption capacity initially, and three species of cyanobacteria were selected for further study based on their performance in the scoping tests. When compared to live controls, autoclaving improved the binding capacities of all three species, but usually biosorption data from experiments with live cells were more consistent. None of the three species was able to bind nickel efficiently in actual effluent samples. Further experimentation indicated that sodium ions, which were present in high concentrations in the effluent, were interfering with the ability of the cells to bind nickel. Adsorption isotherm plots for biosorption of nickel by two species of Anabaena in NiCl2-deionized water solutions were prepared.

Serum urea nitrogen and conception rate: the usefulness of test information

Total of 627 AI in 332 Holstein cows in nine herds were used to examine the relationship between serum urea N and conception rate. Cows were assigned randomly to one of three isocaloric diets varying in protein degradability and content. The AI occurred from 50 to 150 DIM. Mean serum urea N for each cow from 50 to 150 DIM was used to examine conception rate and serum urea N. The clinical interpretation of serum urea N on conception rate is evaluated using Bayes theorem from two approaches (dichotomization vs. continuous). Test information resulting from dichotomization of serum urea N into high and low categories (maximizing the average of test sensitivity and specificity) is compared with likelihood ratio approaches allowing a continuous measure. Likelihood ratio test indicates that conception rate decreases with serum urea N of > 14.9 mg/dl, but dichotomized test suggests that the decrease does not occur until serum urea N is > 20 mg/dl.

Analysis of multiply antimicrobial-resistant isolates of Streptococcus pneumoniae from the United States

Streptococcus pneumoniae isolates resistant to penicillin, chloramphenicol, tetracycline and sulfamethoxazole-trimethroprim are being recovered with increasing frequency in the United States. We analyzed the penicillin-binding proteins (PBPs), multilocus enzyme electrophoresis (MLEE) genotypes, and ribotypes of 22 multiresistant serotype 23F isolates of S. pneumoniae from the United States and 1 isolate each from Spain and South Africa. Also included were seven multiresistant isolates of other serotypes, three penicillin-resistant but chloramphenicol-susceptible serotype 23F isolates, and two penicillin-susceptible isolates (one penicillin-susceptible isolate was serotype 23F). Fifteen of the 22 multiresistant isolates from the United States and the isolates from Spain and South Africa had identical PBP patterns, MLEE profiles, and ribotypes. Six of the remaining seven multiresistant isolates were related by PBP pattern, but demonstrated slightly different MLEE and/or ribotype profiles, possibly because of acquisition of additional resistance markers (four of the six isolates were also resistant to erythromycin). The remaining multiresistant serotype 23F isolate had a unique PBP pattern and ribotype and was only distantly related to the other pneumococcal isolates by MLEE analysis. The PBP patterns, MLEE profiles, and ribotypes of the multiresistant serotype 23F isolates were easily distinguished from those of six multiresistant isolates of other serotypes; three other penicillin-resistant, chloramphenicol-susceptible, serotype 23F isolates; and two penicillin-susceptible isolates. One exception was a multiresistant serotype 19A isolate that was highly related to the clonal group by PBP pattern and MLEE analysis and that had a ribotype similar to those of the other erythromycin-resistant serotype 23F isolates. MLEE analysis and ribotyping were more discriminating than were the PBP patterns in discerning strain differences. These data strongly suggest that a multiresistant clone of S. pneumoniae serotype 23F that is related to multiresistant isolates from Spain and South Africa has become disseminated in the United States. Clinicians should be alerted to the spread of these multiresistant strains in the United States.

Epidemic meningococcal disease in Nairobi, Kenya, 1989. The Kenya/Centers for Disease Control (CDC) Meningitis Study Group

An epidemic of meningococcal disease occurred in Nairobi, Kenya, during 1989, outside the "meningitis belt" of sub-Saharan Africa. About 3800 cases occurred between April and November (250/100,000 population). The case-fatality rate was 9.4% among hospitalized patients. Areas that included Nairobi's largest slums had particularly high attack rates. The epidemic displayed an unusual age distribution, with high attack rates among those 20-29 years old. A vaccination campaign was conducted. By early January, the weekly case count had fallen to 25 from a high of 272 (in September). A case-control study estimated the vaccine efficacy to be 87% (95% confidence interval, 67%-95%). A model estimated that the vaccination campaign reduced the number of cases by at least 20%. Multilocus enzyme electrophoretic typing demonstrated that the strain responsible for this large epidemic is closely related to strains that caused other recent epidemics, documenting further spread of what may be a particularly virulent clonal complex of group A Neisseria meningitidis.

Role of foods in sporadic listeriosis. II. Microbiologic and epidemiologic investigation. The Listeria Study Group

OBJECTIVE

To evaluate the role of foods in sporadic listeriosis.

DESIGN

Microbiologic survey of foods collected from refrigerators of patients with listeriosis identified through active laboratory-based surveillance. Patient and food Listeria monocytogenes isolates were subtyped to identify foods contaminated with the same strain of L monocytogenes that caused illness in the patient; samples of these foods were obtained from the retail source.

SETTING

Multistate population-based study conducted between 1988 and 1990.

RESULTS

Listeria monocytogenes grew from at least one food specimen in the refrigerators of 79 (64%) of 123 listeriosis patients; 11% of more than 2000 food specimens collected in the study contained L monocytogenes. Twenty-six (33%) of 79 refrigerators with foods that grew L monocytogenes contained at least one food isolate of the same strain as that in the corresponding patient, a frequency much higher than would be expected by chance (P less than .001). Multivariate analysis showed that of the food specimens that grew L monocytogenes, foods that were ready-to-eat, foods that grew L monocytogenes by a direct-plating method (a measure of the level of contamination), and foods that contained serotype 4b isolates were independently associated with an increased likelihood of containing the patient-matching strain.

CONCLUSION

We identified specific food and L monocytogenes isolate characteristics--ready-to-eat foods, foods containing higher concentrations of L monocytogenes, and foods containing serotype 4b--which were associated with disease-causing strains. These results can provide guidance to industry and regulatory agencies in developing strategies to prevent listeriosis.

Femoral artery flow and pain during lumbar aortography: comparison of ionic and non-ionic contrast media

A method is described for non-invasively measuring the increase in lower limb blood flow during transfemoral lumbar aortography. Flow measurements were made using a continuous wave Doppler-shift ultrasound transducer placed over the contralateral femoral artery. The effect of the non-ionic contrast medium B15000 (Iopamidol), conventional contrast medium (Urografin 370) and Urografin 370 plus Lignocaine were compared in a double-blind trial. All three produced an increase in flow which reached a peak between 12 and 45 s after injection. The peak flow following Iopamidol was significantly lower than that from both Urografin 370 alone and with addition of Lignocaine. There was a difference of lesser degree between Urografin 370 plus Lignocaine and Urografin 370 alone; however, this was not statistically significant. The subjective assessments of pain and patient 'discomfort' paralleled these objective flow measurements.