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.

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.

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.

Effect of exercise intensity and duration on capillary glucose responses in pregnant women at low and high risk for gestational diabetes.

BACKGROUND: Exercise may influence glucose metabolism during pregnancy. We examined the effect of exercise intensity and duration on capillary glucose responses in pregnant women at low and high risk for gestational diabetes mellitus (GDM) who followed a modified GDM meal plan. METHODS: Randomization occurred at study entry (16-20 weeks' gestation) into a low-intensity [30% heart rate reserve, low risk-30%I, n = 12; high risk-30%I, n = 11] or vigorous-intensity (70% heart rate reserve, low risk-70%I, n = 12; R-70%I, n = 11) exercise program with similar nutritional control. Exercise consisted of walking three to four times a week, gradually increasing time from 25 to 40 min/session. Free-living capillary glucose concentrations were measured once a week pre-exercise and post-exercise. RESULTS: Capillary glucose responses to exercise were strongly influenced by an interaction between GDM risk, exercise duration and exercise intensity (p = 0.006). Decreases in glucose concentrations were observed after 25 (4 ± 13%), 35 (21 ± 12%) and 40 min (15 ± 18%) of walking in high risk-30%I women, with the most noticeable decline after 35 and 40 min. In the high risk-70%I, glucose concentrations decreased significantly only after 25 (22 ± 14%) and 35 min (7 ± 23%) and increasing the exercise time attenuated glucose concentrations decline. In low risk women, regardless of exercise intensity and duration, decreases in glucose concentrations were significant and similar. CONCLUSION: To achieve the best decline in glucose concentrations, pregnant women who follow a modified GDM meal plan should walk for 25 min/session at vigorous intensity or for 35-40 min/session at low intensity if they are at risk for GDM and for at least 25 min at either low or vigorous intensity if they are at low risk for GDM.

Walking program of low or vigorous intensity during pregnancy confers an aerobic benefit.

Walking is the most popular activity during pregnancy and may confer an aerobic benefit. However, the minimum intensity threshold of a maternal walking program for an aerobic conditioning response is unknown. The purpose was to examine the effect of a walking program of a low-intensity (LI, 30% heart rate reserve, HRR) or vigorous-intensity (VI, 70%HRR) on maternal cardiorespiratory responses to a standard submaximal treadmill test. Normal weight pregnant women were randomized at study entry (16-20 weeks of gestation) to the LI (n=23) or VI (n=21) walking program, with nutritional control. Participants performed a steady-state treadmill exercise test at their prescribed intensity pre- and post-intervention (34-36 weeks) to evaluate changes in cardiorespiratory responses. Increasing body mass due to pregnancy was similar between the groups throughout the study. From pre- to post-intervention, relative (mL kg - 1 min - 1) VO2 and VCO2 during steady-state submaximal treadmill exercise did not change in the LI group but decreased in the VI group (- 1.25±2.71, p=0.02 and - 1.50±2.64, p=0.005, respectively). Both groups presented increases in oxygen pulse (p≤0.002). Our results showed that the energy cost of walking was not affected by the increase in maternal body weight in the LI group and was decreased in the VI group, suggesting an aerobic conditioning response in both groups, although the VI group presented a greater response. All women presented similar body mass throughout the intervention and delivered healthy babies, indicating that a prenatal walking program of low or vigorous intensity, combined with healthy eating habits, is safe and beneficial to the mother and fetus.

Viral emergence in marine mammals in the North Pacific may be linked to Arctic sea ice reduction.

Climate change-driven alterations in Arctic environments can influence habitat availability, species distributions and interactions, and the breeding, foraging, and health of marine mammals. Phocine distemper virus (PDV), which has caused extensive mortality in Atlantic seals, was confirmed in sea otters in the North Pacific Ocean in 2004, raising the question of whether reductions in sea ice could increase contact between Arctic and sub-Arctic marine mammals and lead to viral transmission across the Arctic Ocean. Using data on PDV exposure and infection and animal movement in sympatric seal, sea lion, and sea otter species sampled in the North Pacific Ocean from 2001-2016, we investigated the timing of PDV introduction, risk factors associated with PDV emergence, and patterns of transmission following introduction. We identified widespread exposure to and infection with PDV across the North Pacific Ocean beginning in 2003 with a second peak of PDV exposure and infection in 2009; viral transmission across sympatric marine mammal species; and association of PDV exposure and infection with reductions in Arctic sea ice extent. Peaks of PDV exposure and infection following 2003 may reflect additional viral introductions among the diverse marine mammals in the North Pacific Ocean linked to change in Arctic sea ice extent.

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.

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, Ciona intestinalis, 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.