Development of polymorphic markers in the immune gene complex loci of cattle

The addition of cattle health and immunity traits to genomic selection indices holds promise to increase individual animal longevity and productivity, and decrease economic losses from disease. However, highly variable genomic loci that contain multiple immune-related genes were poorly assembled in the first iterations of the cattle reference genome assembly and underrepresented during the development of most commercial genotyping platforms. As a consequence, there is a paucity of genetic markers within these loci that may track haplotypes related to disease susceptibility. By using hierarchical assembly of bacterial artificial chromosome inserts spanning 3 of these immune-related gene regions, we were able to assemble multiple full-length haplotypes of the major histocompatibility complex, the leukocyte receptor complex, and the natural killer cell complex. Using these new assemblies and the recently released ARS-UCD1.2 reference, we aligned whole-genome shotgun reads from 125 sequenced Holstein bulls to discover candidate variants for genetic marker development. We selected 124 SNPs, using heuristic and statistical models to develop a custom genotyping panel. In a proof-of-principle study, we used this custom panel to genotype 1,797 Holstein cows exposed to bovine tuberculosis (bTB) that were the subject of a previous GWAS study using the Illumina BovineHD array. Although we did not identify any significant association of bTB phenotypes with these new genetic markers, 2 markers exhibited substantial effects on bTB phenotypic prediction. The models and parameters trained in this study serve as a guide for future marker discovery surveys particularly in previously unassembled regions of the cattle genome.

Students' Engagement in and Perceptions of Blended Learning in a Clinical Module in a Veterinary Degree Program

Blended learning has received much interest in higher education as a way to increase learning efficiency and effectiveness. By combining face-to-face teaching with technology-enhanced learning through online resources, students can manage their own learning. Blended methods are of particular interest in professional degree programs such as veterinary medicine in which students need the flexibility to undertake intra- and extramural activities to develop the range of competencies required to achieve professional qualification. Yet how veterinary students engage with blended learning activities and whether they perceive the approach as beneficial is unclear. We evaluated blended learning through review of student feedback on a 4-week clinical module in a veterinary degree program. The module combined face-to-face sessions with online resources. Feedback was collected by means of a structured online questionnaire at the end of the module and log data collected as part of a routine teaching audit. The features of blended learning that support and detract from students' learning experience were explored using quantitative and qualitative methods. Students perceived a benefit from aspects of face-to-face teaching and technology-enhanced learning resources. Face-to-face teaching was appreciated for practical activities, whereas online resources were considered effective for facilitating module organization and allowing flexible access to learning materials. The blended approach was particularly appreciated for clinical skills in which students valued a combination of visual resources and practical activities. Although we identified several limitations with online resources that need to be addressed when constructing blended courses, blended learning shows potential to enhance student-led learning in clinical courses.

The major histocompatibility complex homozygous inbred Babraham pig as a resource for veterinary and translational medicine

The Babraham pig is a highly inbred breed first developed in the United Kingdom approximately 50 years ago. Previous reports indicate a very high degree of homozygosity across the genome, including the major histocompatibility complex (MHC) region, but confirmation of homozygosity at the specific MHC loci was lacking. Using both direct sequencing and PCR-based sequence-specific typing, we confirm that Babraham pigs are essentially homozygous at their MHC loci and formalise their MHC haplotype as Hp-55.6. This enhances the utility of the Babraham pig as a useful biomedical model for studies in which controlling for genetic variation is important.

The epidemic of human papillomavirus and oropharyngeal cancer in a Canadian population

BACKGROUND

Sexually transmitted infection with the human papillomavirus (hpv) is responsible for a significant burden of human cancers involving the cervix, anogenital tract, and oropharynx. Studies in the United States and Europe have demonstrated an alarming increase in the frequency of hpv-positive oropharyngeal cancer, but the same direct evidence does not exist in Canada.

METHODS

Using the London Health Sciences Centre pathology database, we identified tonsillar cancers diagnosed between 1993 and 2011. Real-time polymerase chain reaction was then used on pre-treatment primary-site biopsy samples to test for dna from the high-risk hpv types 16 and 18. The study cohort was divided into three time periods: 1993-1999, 2000-2005, and 2006-2011.

RESULTS

Of 160 tumour samples identified, 91 (57%) were positive for hpv 16. The total number of tonsillar cancers significantly increased from 1993-1999 to 2006-2011 (32 vs. 68), and the proportion of cases that were hpv-positive substantially increased (25% vs. 62%, p < 0.002). Those changes were associated with a marked improvement in 5-year overall survival (39% in 1993-1999 vs. 84% in 2006-2011, p < 0.001). When all factors were included in a multivariable model, only hpv status predicted treatment outcome.

INTERPRETATION

The present study is the first to provide direct evidence that hpv-related oropharyngeal cancer is increasing in incidence in a Canadian population. Given the long lag time between hpv infection and clinically apparent malignancy, oropharyngeal cancer will be a significant clinical problem for the foreseeable future despite vaccination efforts.

Role of endolaryngeal surgery (with or without laser) compared with radiotherapy in the management of early (T1) glottic cancer: a clinical practice guideline

AIMS

To provide evidence-based practice guideline recommendations concerning the role of endolaryngeal surgery (with or without laser) compared with radiation therapy for patients with early (T1) glottic cancer, assessing survival, locoregional control, laryngeal preservation rates, and voice outcomes.

METHODS

The medline, embase, and Cochrane Library databases were searched to identify relevant studies from 1996 to 2011. Recommendations were formulated based on that evidence and on the expert opinion of Cancer Care Ontario's Head and Neck Cancer disease site group. The systematic review and practice guideline were externally reviewed by practitioners in Ontario, Canada.

RESULTS

The available evidence was of a level insufficient to demonstrate a clear difference between treatment options when considering the likelihood of local control or overall survival. Although the evidence was mainly retrospective, there was a suggestion that, compared with surgery, radiotherapy might be associated with less measureable perturbation of voice without a significant difference in patient perception. The likelihood of laryngeal preservation may be higher when surgery can be offered as initial treatment.

CONCLUSIONS

For patients with early (T1) glottic cancer, the evidence is insufficient to demonstrate a difference between endolaryngeal surgery (with or without laser) and external-beam radiation therapy. The choice between treatment modalities has been based on patient and clinician preferences and general medical condition.

Explaining socioeconomic status effects in laryngeal cancer

INTRODUCTION

People with lower socioeconomic status (SES) experience shorter survival times after a cancer diagnosis for many disease sites. We determined whether area-level SES was associated with the outcomes: cause-specific survival and local-regional failure in laryngeal cancer in Ontario, Canada. When we found an association we sought explanations that might be related to access to care including age, sex, rural residence, tumor stage, lymph node status, use of diagnostic imaging, treatment type, percentage of prescribed radiotherapy delivered, number of radiotherapy interruption days, treatment waiting time, and treating cancer center.

MATERIALS AND METHODS

The study population consisted of 661 glottic and 495 supraglottic stage-stratified randomly-sampled patients identified using the Ontario Cancer Registry. Area-level SES quintiles were assigned using adjusted median household income from the Canadian Census. Other data were collected from patient charts. Explanations for SES effects were determined by measuring whether the effect moved toward the null value by at least 10% when an access indicator was added to a the model.

RESULTS

Socioeconomic status was not related to either outcome for those with supraglottic cancer, but an association was present in glottic cancer. With the highest socioeconomic status quintile as the referent group, the relative risks for patients in the lowest socioeconomic quintile were 2.75 (95% CI 1.48, 5.12) for cause-specific survival and 1.90 (95% CI 1.24, 2.93) for local-regional failure. Disease stage as measured by T-category explained between 3% and 23% of these socioeconomic effects. None of the other access indicators met our 10% change criterion.

CONCLUSION

We question why people in lower socioeconomic quintiles were not diagnosed earlier in the disease progression. Having ruled out several variables that may be related to access to care, additional biologic and social variables should be examined to further understand socioeconomic status effects.

Cloning of a glycosylphosphatidylinositol-anchored alpha-2-macroglobulin cDNA from the ascidian, , and its possible role in immunity

Molecular approaches were used to study thiolester-containing genes in the ascidian, Ciona intestinalis. RT-PCR, RACE and genome mining revealed that this animal expresses not only conventional alpha-2-macroglobulin (alpha2m) and two forms of C3 but also a gene encoding a glycosylphosphatidylinositol (GPI)-anchored alpha2m. Previously, GPI-anchored alpha2ms have been reported only for humans and mice. We propose that GPI-anchored alpha2ms constitute a third subgroup of the alpha2m superfamily and may represent an important evolutionary stage in the phylogeny of the thiolester containing proteins. Its occurrence in an ascidian shows its origin pre-dates the evolution of the vertebrates. In C. intestinalis this GPI-anchored alpha2m, designated Ciona alpha2m-GPI, is expressed in the hepatopancreas, circulating coelomic blood cells and the gut of adults. It is also expressed in 3-5 days old larvae. Its tissue distribution coupled with its sequence characteristics and unusual domain structure indicate that the encoded protein probably assists in host defence by entrapping and inhibiting proteases from micro-organisms.

Radiotherapy patterns of practice: T1N0 glottic cancer in Ontario, Canada

AIMS

To describe the variation in the delivery of radiation therapy to patients with T1N0 glottic cancer who were diagnosed in Ontario, Canada, between 1982 and 1995.

MATERIALS AND METHODS

The patient population consisted of a random sample of 461 patients treated with curative intent from the nine cancer centres that administer radiation therapy in the province. Abstracted variables included prescribed dose (Gy) and fractionation (f), beam energy and arrangement, set-up, field size, beam modifiers, positioning and treatment interruptions.

RESULTS

Thirteen prescribed dose-fractionation schemes (> or = four cases each) were identified, including 50.0-53.0 Gy/20 f (54.5%), 55.0-61.0 Gy/25 f (30.3%), and 60.0-66.0 Gy/30-33 f (7.7%). All regimens used one fraction per day, 5 days per week. An isocentric set-up was used (94.3%), with megavoltage (MV) beam energies of Cobalt-60 (87.9%), 6 MV (6.1%) and 4 MV (6.1%). A lateral parallel-opposed pair of beams was the predominant technique (76.4%) versus an anterior oblique pair (17.2%) or angle-down pair (caudally directed fields to achieve shoulder clearance, 5.7%). Wedging (96.3%) and bolus (11.8%) were used as beam-modifying devices. Predominant field-width dimensions were 5.0-6.0 cm (43.4%) and 6.5-7.0 cm (43.1%), and field length dimensions were 5.0-6.0 cm (49.5%) and 6.5-7.0 cm (35.0%). Head, neck or chin immobilisation was used in 86.9% of the cases, with 94.6% of these being custom-made. We found that radiotherapy practice was stable over time, except for a trend of increasing field size and increasing use of immobilisation. In contrast, we found practice variations among the province's cancer centres. On the basis of our findings, we defined a predominant technical practice consisting of Cobalt-60 (reflecting machine availability during the period of the study), an isocentric set-up, a lateral parallel-opposed pair technique with wedging, and supine-head neutral positioning with custom immobilisation. Forty-two per cent of the cases had one or more components of treatment that differed from this definition.

CONCLUSIONS

Description of practice variation can provoke discussion about unrecognised differences in practice policies, perhaps identifying the need for better evidence, treatment guidelines, or both.

Lipopolysaccharide induces DNA-synthesis in a sub-population of hemocytes from the swimming crab, Liocarcinus depurator

The swimming crab, Liocarinus depurator, contains a small proportion of circulating blood cells which enter S-phase in vitro, as revealed by BrdU assay. These cells are enriched within the semigranular cell band produced by density gradient centrifugation on Percoll and their proportion is significantly higher in blood samples taken from crabs injected 3h previously with lipopolysaccharide (LPS). The occurrence of these cells does not persist as blood samples taken 12h post-injection show similar numbers of these cells to those from saline-treated and untreated controls. However, their appearance appears to be dose related; hemolymph from animals given 15 microg LPS per animal contains greater numbers than that from animals given LPS doses of 0.15 or 0.015 microg per animal. Estimation of the probable number of these cells per ml of the hemolymph, taking into account cell viability and changes in the size of the semigranular cell pool, indicates that they are very rare, comprising merely ca 0.06% of the total cell count. Notwithstanding, this still represents a baseline population in the region of 1.25 x 10(4) ml-1. More importantly, their number rises, approximately 11-fold to ca 14 x 10(4) ml-1 of hemolymph by 3h of injection of LPS. These results show that certain hemocytes from a brachyuran crab can synthesise DNA in vitro, and offers evidence that these cells constitute a rare but distinct sub-population of hemocytes that co-migrate with the semigranular cells during density gradient centrifugation. Since the cells received the stimulus to enter S-phase in vivo, the response must represent one of the mechanisms used by decapods to restore the hemocyte number in the circulation after non-self challenge.

A comparison of ON-PUMP vs OFF-PUMP coronary artery bypass surgery among low, intermediate, and high-risk patients: the Hartford Hospital experience

BACKGROUND

Off-pump coronary artery bypass (OP-CAB) graft surgery is being used with increasing frequency. This study was designed to compare OP-CAB outcomes with conventional surgical revascularization using cardiopulmonary bypass (CPB) in patients with varying risk categories at a high-volume center.

METHODS AND RESULTS

Between 1/1/1999 and 1/31/2001, bypass surgery was performed on 1,312 patients, including 348 OP-CAB cases and 964 CPB cases. Compared to CPB cases, OP-CAB patients were more likely to be female and had a lower incidence of three vessel coronary artery disease, prior percutaneous intervention, and prior bypass surgery. Postoperatively, OP-CAB patients had a lower incidence of renal failure and prolonged ventilatory support, as well as a lower composite endpoint of inhospital mortality, perioperative myocardial infarction, cerebrovascular accident, and/or renal failure. In addition, OP-CAB patients required fewer transfusions and had a shorter total length of hospital stay. In general, morbidity and mortality increased in both OP-CAB and CPB groups with increasing Parsonnet score.

CONCLUSIONS

OP-CAB surgery is a safe and effective alternative to conventional coronary artery bypass graft (CABG) surgery, with a lower incidence of major in-hospital adverse clinical events and a decreased requirement for medical resources. Adverse OP-CAB outcomes correlate well with pre-operative Parsonnet Score.

Isolation and characterization of magbane, a magnesium-lethal mutant of paramecium

Discerning the mechanisms responsible for membrane excitation and ionic control in Paramecium has been facilitated by the availability of genetic mutants that are defective in these pathways. Such mutants typically are selected on the basis of behavioral anomalies or resistance to ions. There have been few attempts to isolate ion-sensitive strains, despite the insights that might be gained from studies of their phenotypes. Here, we report isolation of "magbane," an ion-sensitive strain that is susceptible to Mg2+. Whereas the wild type tolerated the addition of > or =20 mm MgCl2 to the culture medium before growth was slowed and ultimately suppressed (at >40 mm), mgx mutation slowed growth at 10 mm. Genetic analysis indicated that the phenotype resulted from a recessive single-gene mutation that had not been described previously. We additionally noted that a mutant that was well described previously (restless) is also highly sensitive to Mg2+. This mutant is characterized by an inability to control membrane potential when extracellular K+ concentrations are lowered, due to inappropriate regulation of a Ca2+-dependent K+ current. However, comparing the mgx and rst mutant phenotypes suggested that two independent mechanisms might be responsible for their Mg2+ lethality. The possibility that mgx mutation may adversely affect a transporter that is required for maintaining low intracellular Mg2+ is considered.

Effects of head and neck radiation therapy on vocal function

OBJECTIVE

Radiotherapy (RT) is used to treat a variety of head and neck malignancies. The larynx may receive high radiation doses even in the absence of disease. The effects of RT on the nondiseased larynx are unknown. This study will evaluate subjective and objective parameters of vocal function in patients treated with RT for nonlaryngeal malignancies.

DESIGN

Cross-sectional observational study.

METHODS

Videostroboscopic, aerodynamic, and acoustic analyses were performed. Results were compared to age- and gender-matched controls. Self-assessment of voice quality was measured using the Voice Handicap Index.

RESULTS

A majority of patients demonstrated increased supraglottal activity (i.e., ventricular fold constriction) during stroboscopic evaluation. Significant differences compared to normative data were found in many aerodynamic and acoustic parameters. A substantial proportion (27%) of patients reported significant voice handicap. Younger patients reported greater handicap, and voice quality was worse with time.

CONCLUSIONS

Significant objective and subjective changes in vocal function occur in patients radiated for nonlaryngeal head and neck malignancies. Young patients may have the worst impact, and vocal dysfunction may increase with time. A prospective study of this patient population should include a baseline voice quality assessment.

Glottic cancer in Ontario, Canada and the SEER areas of the United States. Do different management philosophies produce different outcome profiles?

We compared the management and outcome of glottic cancer in Ontario, Canada to that in the Surveillance, Epidemiology and End Results (SEER) Program areas in the United States to determine whether the greater use of primary radiotherapy with surgery reserved for salvage in Ontario was associated with similar survival and better larynx retention rates than the U.S. approach where primary surgery is used more often. Electronic, clinical and hospital data were linked to cancer registry data and supplemented by chart review where necessary. Initial treatment and survival in patients diagnosed in the SEER areas from 1988 through 1994 were compared to patients from Ontario diagnosed from 1982 through 1995. Actuarial laryngectomy rates were compared for patients over 65 at diagnosis in the two regions. Analyses were conducted over all cases and stratified by disease stage. In localized disease (T1 or T2), conservative treatment was the most common initial treatment in both regions, although total laryngectomy was used more often in SEER than Ontario (6.2% vs. 0.2%, respectively, P <.001). In advanced disease (T3 or T4), total laryngectomy was more commonly used as initial treatment in SEER (62.9% vs. 21.0% in Ontario, P < or =.001). Over all cases, the relative survival rate was 80% in Ontario at 5 years compared to 78% in SEER (P =.33). In localized disease, the relative survival rates were 4 to 5% higher in Ontario from the second year on, while in advanced disease 2 to 3% higher rates in SEER did not approach statistical significance. Actuarial laryngectomy rates at 3 years differed between the two regions, with a 4% higher rate in SEER (P =.01). In localized disease, 12.6% of Ontario patients had a laryngectomy by 3 years postdiagnosis compared to 17.9% in SEER (P =.05). In advanced disease, the rates were 63.3% and 79.2%, respectively (P =.07). There are large differences in the management of glottic cancer between the SEER areas of the U.S. and Ontario and no evidence that a policy emphasizing radiotherapy with surgery reserved for salvage is associated with worse survival. Ultimate laryngectomy rates are lower in Ontario for localized disease and may be lower for advanced disease. Conservation treatment should be used for localized disease while the treatment decision in advanced disease may be especially sensitive to patient values for voice retention versus initial cure.

The role of computed tomography in the T classification of laryngeal carcinoma

BACKGROUND

The objectives of this study were 1) to describe patterns of use of computed tomography (CT) in laryngeal carcinoma, and 2) to characterize the contribution of CT to the T classification of laryngeal carcinoma.

METHODS

The study population comprised 1195 patients with laryngeal carcinoma diagnosed from 1982 through 1995 chosen randomly from the Ontario provincial cancer registry. A chart review was conducted to obtain data on each case. Patient-related, tumor-related, and health-system-related factors were analyzed to identify factors associated with the use of CT. Descriptions of clinical exams and CT reports were reviewed to see how CT information modified T classification. Actuarial local control and cause specific survival curves were plotted by clinical T classification without and with CT to evaluate stage migration. The percentage of the variance in outcome explained by T classification in a Cox analysis was used to evaluate whether the prognostic accuracy of T classification was improved with the use of information from CT.

RESULTS

Patients with glottic (20.1%) and supraglottic (41.7%) carcinoma underwent CT. The use of CT increased over time in glottic and supraglottic carcinoma combined from 17.2% in 1982-5 to 33.9% in 1991-5. Computed tomography was used less often in older patients with a 16% (95% confidence interval, 5-27%) decrease in the odds of having CT with each 10-year age increment. Computed tomography use varied considerably across the cancer center regions in Ontario. Computed tomography altered the T classification in 20.2% of those patients who had CT, with most being "upstages." Stage migration due to CT was demonstrated. Using information from CT in the assignment of T classification for 27.8% of this study population did not make a significant contribution to the ability of T classification to predict outcome over the entire group.

CONCLUSIONS

There is large variation in the use of CT among different age groups and regions. The ability to compare outcomes by stage across geographic areas is compromised when the use of CT varies.

Ca(2+) current-deficient pawn mutants are promoted to queens during chronic depolarization of Paramecium tetraurelia

Chronic KCl-induced depolarization of Paramecium tetraurelia enhances Ca(2+)-dependent backward swimming behavior over a period of 8-24 hr. Here, we investigated the electrophysiological mechanisms underlying this adaptive phenomenon using voltage-clamp techniques. Cells that had been adapted to 20 mm KCl showed several significant changes in the properties of the Ca(2+) current that mediates ciliary reversal in Paramecium (I(Ca)), including a positive shift in voltage sensitivity and a significant slowing of inactivation. In seeking an explanation for these changes, we examined the effects of chronic depolarization on mutants that do not normally express a Ca(2+) current or swim backward. Surprisingly, pawn B mutant cells slowly regained the ability to reverse their cilia during KCl exposure with a time course that mirrored behavioral adaptation of the wild type. This behavior was accompanied by expression of a novel Ca(2+) current (I(QUEEN)) whose voltage sensitivity was shifted positive with respect to the wild-type Ca(2+) current and that was slow to inactivate. Coincidental expression of I(QUEEN) in the wild type during adaptation would readily explain the observed changes in I(Ca) kinetics. We also examined the effects of chronic depolarization on Dancer, a mutant suggested previously to have an I(Ca) inactivation defect. The mutant phenotype could be suppressed or exaggerated greatly by manipulating extracellular KCl concentration, suggesting that Dancer lesion instead causes inappropriate regulation of I(QUEEN).

Correlation between loss of a Mg2+ conductance and an adaptation defect in a mutant of Paramecium tetraurelia

Paramecium tetraurelia responds to chronic KCl-induced depolarization by swimming backward, but the ciliate recovers within seconds and then undergoes a prolonged adaptation period during which sensitivity to external stimuli is altered radically. We examined the role of Mg2+ in this phenomenon, prompted by finding that mutations in the eccentric-A gene both suppressed a Mg(2+)-specific conductance and prevented adaptation. Adaptation of the wild type proceeded normally when extracellular Mg2+ was varied from 0-20 mM, however, suggesting that channel-mediated Mg2+ fluxes were not involved. In seeking alternative explanations for the eccentric mutant phenotype, we ascertained that there was an osmotic component to adaptation but that K(+)-induced depolarization was the primary stimulus. We also noted that wild-type and eccentric mutant cells depolarized by equivalent amounts in KCl, suggesting that the genetic lesion must lie downstream of membrane-potential change. We also examined whether the adaptation-induced behavioral changes and, indeed, the defect in eccentric might be explained in terms of Mg2+ and Na+ efflux during behavioral testing, but experimental observations failed to support this notion. Finally, we consider the possibility that eccentric gene mutation prevents adaptation by interfering with intracellular free Mg2+ homeostasis in Paramecium.

Long-term adaptation of Ca2+-dependent behaviour in Paramecium tetraurelia

Prolonged exposure to KCl has long been recognized to modify swimming behaviour in Paramecium tetraurelia, a phenomenon known as 'adaptation'. In this study, we have investigated behavioural adaptation systematically. A 24 h exposure to 30 mmol l-1 KCl deprived cells of the ability to respond behaviourally to two established chemoeffectors. We also explored the effects of 30 mmol l-1 KCl on the duration of backward swimming induced by Ba2+ and Mg2+. A brief (60 min) exposure prevented cells from swimming backwards in response to either cation, but recovery was rapid (&lt;60 min) following a return to control medium. Prolonged (48 h) exposure caused a more persistent loss of response to Ba2+, so that several hours was now required for recovery. Surprisingly, responses to Mg2+ reappeared during 6-8 h in KCl, with backward swimming durations increasing to more than 300 % of control values after 26 h. Thus, we can distinguish two phases to adaptation. The short-term phase is characterized by an inability to respond behaviourally to most stimuli and might be adequately explained in terms of Ca2+ channel inactivation and K+-induced shifts in membrane potential. The long-term phase is characterized by enhanced responses to Mg2+ (and also to Na+), suggesting that a more extensive reprogramming of membrane excitability may occur during chronic K+-induced depolarization.

A better long-term outcome in cardiac transplant recipient with a history of previous open heart operations

OBJECTIVE

To investigate the effect of previous open heart operations (POHO) on the outcome of heart transplantation (HTX).

METHODS

Between November 1984 and May 1996, HTX was performed on 151 patients at Hartford Hospital. Among them, 61 patients had previous open heart operations (POHO) (group A), and 90 did not (group B). The average follow-up period was 1615 +/- 1185 days for group A and 1330 +/- 1125 days for group B. The recipient age was 55 +/- 10 years for group A and 48 +/- 12 years for group B (P < 0.01). There were 17 patients (26%) in group A and 14 (50%) in group B who were over 60 years of age. There was more coronary artery disease (74% versus 37%, P < 0.001) as etiology, and more diabetics in group A (P < 0.02).

RESULTS

The time for cardiopulmonary bypass (133 +/- 20 min versus 106 +/- 18 min, P < 0.01) and aortic clamp time (73 +/- 16 min versus 61 +/- 13 min, P < 0.01) were longer in group A. The operative mortality (within 30 days) was 0 and 2.2%, and the cumulative deaths were 16 (26%) and 43 (48%) respectively for group A and group B (P < 0.01). The causes of death were (group A vs group B): infection (31% vs 26%), rejection (13% vs 28%, P < 0.05), malignancy (25% vs 16%), cardiac event (6% vs 14%) and others (25% vs 16%). In patients over 60, there were 4 deaths (24%) in group A and 7 (50%) in group B. The difference was not significant. No patients died of rejection in this subgroup. The actuarial survival rates in group A versus group B were: 1 year, 93% versus 83%; 2 years, 85% versus 74%; 3 years, 81% versus 71%; 5 years, 76% versus 58%; and 10 years, 57% versus 24% (P < 0.01).

CONCLUSION

The survival rate in patients who had POHO is much higher than that in patients who had HTX as their primary operation.

Comparison of production losses caused by chronic Fasciola gigantica infection in yearling Friesian and Boran cattle

Yearling Friesian and Boran cattle were given a standard dose of Fasciola gigantica metacercariae designed to produce chronic infection. Their liveweights were then monitored for 23 weeks post-infection. Following standard meat inspection procedures, all the livers from the infected cattle were condemned. At 22 kg per animal, the mean reduction in liveweight gain in infected Borans was significantly greater than in infected Friesians. Compared to the control cattle and based on current sale prices in Kenya, the production losses from the combination of liver condemnations and reduction in liveweight gain constituted a loss in value of US$$12.11 (4.92%) and US$23.41 (10.34%) for Friesians and Borans respectively. These data indicate that productivity losses and the economic consequencies of fasciolosis in yearling Boran cattle are much more severe than in Friesians. These findings have implications for assessing the likely benefits of control measures against this parasite.

Phenotypic and genetic analysis of "Chameleon," a paramecium mutant with an enhanced sensitivity to magnesium

Three mutant strains of Paramecium tetraurelia with an enhanced sensitivity to magnesium have been isolated. These new "Chameleon" mutants result from partial- or codominant mutations at a single locus, Cha. Whereas the wild type responded to 5 mM Mg2+ by swimming backward for 10-15 sec, Cha mutants responded with approximately 30 sec backward swimming. Electrophysiological analysis suggested that this behavior may be caused by slowing in the rate at which a Mg(2+)-specific ion conductance deactivates following membrane excitation. This would be consistent with an observed increase in the sensitivity of Cha mutants to nickel poisoning, since Ni2+ is also able to enter the cell via this pathway. More extensive behavioral analysis showed that Cha cells also overresponded to Na+, but there was no evidence for a defect in intracellular Ca2+ homeostasis that might account for a simultaneous enhancement of both the Mg2+ and Na+ conductances. The possibility that the Cha locus may encode a specific regulator of the Mg(2+)- and Na(+)-permeabilities is considered.

Inoculation of culture plates: straightforward or is it?

In view of the recent vogue in some genitourinary medicine (GUM) units towards selective microscopy we aimed to assess the adequacy of culture plate inoculation in our own GUM clinic by the visual examination of 350 consecutively inoculated plates. Seventy-five (21%) plates were inoculated so lightly that no indentation in the agar could be seen whilst in 20 (60%) the agar was shredded. Eighty-five per cent of inadequately plated samples were inoculated by the same staff members who were either relatively inexperienced, or well-distanced from their last in-service training. This has many important implications not only in the identification and control of infection but also with respect to staff training. We have now introduced practical plating instruction for all new members of clinical staff and additional in-service training. We plan to repeat the audit in 6 months' time to assess the effect of these changes.

Prospects for plant anthelmintics in tropical veterinary medicine

The current use of anthelmintic plants in tropical veterinary medicine is reviewed and attention is drawn to the lack of scientific evidence for the effectiveness of many now in use. The case for anthelmintic plants as a means of overcoming some of the serious limitations of manufactured anthelmintics is outlined. Reasons why anthelmintic plants are not generally used in veterinary medicine, in contrast to their greater acceptance in human medicine, are considered. Strategies for their development and use are discussed, in particular the need for in vivo trials to identify those plants which are effective and suitable for general use: attention is drawn to possible candidates, including pyrethrum and papaya latex. Those helminths of most economic importance should be targeted first. Anthelmintic plants offer a traditional alternative to manufactured anthelmintics that is both sustainable and environmentally acceptable. Such plants could have a more important role in the future control of helminth infections in the tropics.

Studies on helminthosis at the Centre for Tropical Veterinary Medicine (CTVM)

The research work relating to helminths, which has been conducted within the Helminthology Section of the CTVM, often in collaboration with colleagues from the tropics is reviewed and placed into a historical perspective. The research has, in the main, concentrated on the trematodes Fasciola hepatica and Fasciola gigantica and the cestodes Taenia saginata and Taenia solium, but work on other parasites including gastro-intestinal nematodes is also considered. All of these parasites are of obvious veterinary/economic importance particularly in the tropics and subtropics. While the zoonotic importance of T. saginata and T. solium has been recognised for many years, it is only more recently that the zoonotic impact of Fasciola spp. has been generally acknowledged.

Eucalyptus: a sustainable self-delivery molluscicide?

Attention is drawn to the limitations of conventional methods of controlling important trematode infections such as schistosomosis and fasciolosis. Plant molluscicides could have a role in the future control of these infections. There are, however, major problems with most plant molluscicides in that their use is labour-intensive, in many cases relatively skilled workers are required, they must be applied regularly and arable land may be required for their cultivation. Thus, little progress is to be expected until plant species with sustainable self-delivery systems are identified. Eucalyptus is proposed as a likely candidate. The leaves of many species in this genus have molluscicidal properties and their intermittent fall could effect self-delivery if the trees were planted in appropriate places. Relatively little work has been carried out on this possibility and much more is necessary, especially field trials. Before field trials are started, more laboratory testing is also necessary to determine the LC50 values for different snail species and to study toxicity to non-target organisms.

Female patients' attitudes to mammography screening

This study compares the attitudes of women who chose or chose not to have mammography screening. Women personally invited by their physicians to have mammography were more likely to go for screening. Those who did not go for screening were more afraid of medical tests and were less likely to want to know whether they had cancer.

Mother, doctor, wife

Women physicians often play a triple role: mother, doctor, and wife. This situation can be extremely stressful. Understanding the stresses of each role and setting priorities to help make each role more fulfilling are important for balancing career and personal life.

Sterilization and its behavioral effects on free-ranging female rhesus monkeys (Macaca mulatta)

In order to control population growth rates, a decision was made to sterilize most of the free-ranging, wild rhesus macaque females of Silver Springs, Florida. Between October 1987 and March 1988, the five females who had been sterilized and released in the fall of 1986 were matched with five intact females in a behavioral study. While there were differences between the behaviors of the sterilized and intact females, the differences can be attributed more to differences in age, rank, and other factors than to the sterilization. Clinical data collected and reported on the monkeys is unremarkable.

University of Edinburgh veterinary expeditions: 1966 to 1986

Since 1966, teams of new graduates from the Royal (Dick) School of Veterinary Studies have organised eight veterinary research expeditions to Africa, tropical America and the Seychelles. The expeditions are now a regular feature of the school's activities. It is now possible to look back, learn and advise on future expeditions regarding timing, research and funding.

Susceptibility to varicella-zoster virus among adults at high risk for exposure

The adult health care provider who is susceptible to varicella zoster virus (VZV) represents a risk to her or himself and to patients. Nineteen percent of employees at this Children's Hospital had no or uncertain prior experience with VZV, and of these, 28% were found to be VZV susceptible, representing 5% of the total population of 2,730 hospital employees. During the 12 months of study, six of the potential 135 to 137 VZV-susceptible individuals acquired varicella. VZV-susceptible health care providers should be aware of their potential to both acquire and transmit VZV.

Radical irradiation and misonidazole for T2 grade III and T3 bladder cancer: 2 year follow-up

Patients with T2 grade III and T3 bladder cancer were treated in a Phase II trial of radical irradiation plus Misonidazole (MISO). Forty Gy in 2 Gy fractions (5 per week) to the whole pelvis were followed by 12 Gy in 6 Gy fractions (1 per week) plus oral and intravesical MISO to a coned down volume. Twenty-two patients were treated and the results compared with historical controls. The cystoscopic complete tumor response between 6 and 12 months post therapy were 73 and 43%, respectively. The patient two year survival was 81 and 51%, respectively, and the patient 2 year survival with bladder preservation was 61 and 48%, respectively--4 patients in the MISO study having undergone salvage cystectomy. Complications that may be radiation related in the MISO study are wound sepsis after salvage cystectomy in 2 patients, rectal stenosis requiring colostomy 16 months after salvage cystectomy in 1 patient and the development of a contracted bladder in 1 patient with a history of prior extensive endoscopic therapy. No misonidazole neurotoxicity seen. These findings are being further evaluated in a prospective randomized trial.

Resistance to Fasciola hepatica in rats and rabbits following implantation of adult flukes contained in diffusion chambers

Resistance to Fasciola hepatica could be elicited in rats by implanting mature flukes subcutaneously or intraperitoneally in diffusion chambers. A similar resistance occurred even when the implants were removed two weeks before challenge. This excluded the possibility that the continuing presence of the sensitising flukes was necessary for the maintenance of resistance and also showed that the resistance could be elicited by only two weeks exposure to diffusible immunogens emanating from the flukes.

Resistance of Fasciola hepatica in rats and rabbits following sensitising infection and treatment

Whereas one mature or two immature infections with Fasciola hepatica, which had been eliminated by anthelmintic treatment, conferred resistance to reinfection in rats, this did not occur with rabbits. The differences between the hosts were shown by the numbers of flukes which developed following challenge ands by the changes in peripheral eosinophil counts and serum glutamic dehydrogenase levels. In contrast, rabbits gave a stronger serological response (ELISA) than rats but this was not affected by treatment or challenge in either host.

Influence of acoustic reflex on pure-tone thresholds in sensorineural patients

Discrete-frequency Bekesy HTLs (.25, .5, 1, and 2 kc/s) of 12 sensorineural impaired Ss (8 bilateral, 4 unilateral) were compared under 3 conditions to determine the influence of the acoustic reflex (AR). The conditions were (1) tones in quiet, (2) tones with contralateral noise 20 db below the AR threshold for noise, and (3) tones with contralateral noise 10 db above AR threshold. The results revealed statistically and clinically significant threshold shifts due to the AR. Clinical implications were discussed.

The planning and construction of veterinary investigation laboratories in tropical and sub-tropical countries. IV. Ancillary buildings and carcass disposal

Suggestions are made for the siting and construction of a post mortem unit, animal accommodation and other ancillary buildings for veterinary investigation laboratories in tropical and sub-tropical countries. The disposal of carcasses and other waste is also considered.