Mapping of the oat crown rust resistance gene Pc91.

Crown rust is an important disease of oat caused by Puccinia coronata Corda f. sp. avenae Eriks. Crown rust is efficiently and effectively managed through the development of resistant oat varieties. Pc91 is a seedling crown rust resistance gene that is highly effective against the current P. coronata population in North America. The primary objective of this study was to develop DNA markers linked to Pc91 for purposes of marker-assisted selection in oat breeding programs. The Pc91 locus was mapped using a population of F7-derived recombinant inbred lines developed from the cross 'CDC Sol-Fi'/'HiFi' made at the Crop Development Centre, University of Saskatchewan. The population was evaluated for reaction to P. coronata in field nurseries in 2008 and 2009. Pc91 mapped to a linkage group consisting of 44 Diversity Array Technology (DArT) markers. DArTs were successfully converted to sequence characterized amplified region (SCAR) markers. Five robust SCARs were developed from three non-redundant DArTs that co-segregated with Pc91. SCAR markers were developed for different assay systems, such that SCARs are available for agarose gel electrophoresis, capillary electrophoresis, and Taqman single nucleotide polymorphism detection. The SCAR markers accurately postulated the Pc91 status of 23 North American oat breeding lines.

Electrophysiology of rabbit Müller (glial) cells in experimental retinal detachment and PVR.

PURPOSE: To determine the electrophysiological properties of Müller (glial) cells from experimentally detached rabbit retinas. METHODS: A stable local retinal detachment was induced by subretinal injection of a sodium hyaluronate solution. Müller cells were acutely dissociated and studied by the whole-cell voltage-clamp technique. RESULTS: The cell membranes of Müller cells from normal retinas were dominated by a large inwardly rectifying potassium ion (K+) conductance that caused a low-input resistance (<100 M(Omega)) and a high resting membrane potential (-82 +/- 6 mV). During the first week after detachment, the Müller cells became reactive as shown by glial fibrillary acidic protein (GFAP) immunoreactivity, and their inward currents were markedly reduced, accompanied by an increased input resistance (>200 M(Omega)). After 3 weeks of detachment, the input resistance increased further (>300 M(Omega)), and some cells displayed significantly depolarized membrane potentials (mean -69 +/- 18 mV). When PVR developed (in 20% of the cases) the inward K+ currents were virtually completely eliminated. The input resistance increased dramatically (>1000 MOmega), and almost all cells displayed strongly depolarized membrane potentials (-44 +/- 16 mV). CONCLUSIONS: Reactive Müller cells are characterized by a severe reduction of their K+ inward conductance, accompanied by depolarized membrane potentials. These changes must impair physiological glial functions, such as neurotransmitter recycling and K+ ion clearance. Furthermore, the open probability of certain types of voltage-dependent ion channels (e.g., Ca2+-dependent K+ maxi channels) increases that may be a precondition for Müller cell proliferation, particularly in PVR when a dramatic downregulation of both inward current density and resting membrane potential occurs.

Peripheral plasma progesterone and oestradiol concentrations associated with successful and unsuccessful recovery of uterine embryos in rhesus monkeys with and without intra-uterine devices.

Concentrations of progesterone and oestradiol were measured in peripheral plasma samples collected at the time when the uteri of rhesus monkeys with an intra-uterine device (IUD) and those without an IUD were flushed in attempts to recover uterine embryos. The proportion of successful attempts in IUD-bearing monkeys was much lower than in the non-IUD-bearing animals. Steroid measurements indicated that this reduced success rate was not due to an effect of the IUD on the timing of ovulation within the menstrual cycle or to a steroid-mediated disturbance in the rate of embryo transport to the uterine lumen. Successful embryo recoveries were associated with a higher progesterone concentration, suggesting that one reason for failure was that the attempt had been made too close to ovulation. There was no evidence of any asymmetry between the left or right ovaries in their ovulatory or steroidogenic activity.

"Tripolar system" for transvenous atrioventricular pacing.

A ventricular inhibited unipolar pacing system in a case of so-called pacemaker syndrome was successfully converted into an atrioventricular sequential system without replacing the ventricular lead.

Aortic valvular insufficiency and postductal aortic coarctation in the adult. Combined surgical management through median sternotomy: a new surgical approach.

A new surgical technique for the relief of aortic coarctation and replacement of the aortic valve has been described. In our patient, aortic valve replacement was combined with a bypass graft from the ascending aorta to the retrocardiac descending thoracic aorta. The clinical findings and the technical details form the basis of this report.

Celiac artery aneurysmectomy: case report with review of the literature.

A case of celiac trunk aneurysm treated by excision and direct reanastomosis with restoration of arterial continuity, and a description of a new technique for selective visualization of the celiac artery are reported. A review of the literature with tabulation of all surgically treated cases is included. Significance of hepatic artery flow restoration is emphasized.

Temperature-related pacemaker tachycardia.

A case of sudden increase in rate of an implanted ventricular-inhibited pacemaker is reported. Testing of the unit at room temperature revealed the measurements to be entirely within normal limits. Subsequent electrical testing at a temperature of 38 degrees C confirmed the abrupt increase in rate of the unit.

Results of coronary bypass surgery in elderly women.

One hundred two female and 102 male patients all older than 70 years who underwent coronary artery bypass grafting (CABG) between 1978 and 1983 were matched according to age, anginal status, ejection fraction (EF), number of bypass grafts, and year of operation. These 204 patients were characterized by a mean age of 73 years, a mean EF of 64%, a mean of 3.2 bypass grafts per patient, and unstable angina in 82%. Statistical analyses were performed on the following variables in conjunction with patient sex to determine whether the two samples (women and men) can be considered representative of a single patient population: preoperative resting ECG, stress test result, number of diseased vessels, left ventricular end-diastolic pressure, presence of carotid artery disease, use of an internal mammary artery graft, incidence of operative death, perioperative myocardial infarction (MI), hospital complications, late MI, recurrent angina, late death, and cumulative survival. All differences were small and failed to reach statistical significance except that women had a higher incidence of recurrent angina-like chest pain and a higher incidence of ischemic changes in the preoperative ECG and men had a higher incidence of conduction abnormalities. We conclude that in this age group, CABG is equally beneficial to women and men in terms of survival, but may result in less subjective symptomatic benefit in women.

Implantation of permanent transvenous atrial J lead using lateral view fluoroscopy.

Fifty consecutive, tined, atrial J leads were implanted for atrial and atrioventricular sequential pacing using lateral view fluoroscopy for atrial lead manipulation and positioning. The technique is described in detail. It is concluded that lateral view fluoroscopy allows a more expeditious and reliable positioning in the right atrial appendage.

Surgical treatment of 200 consecutive patients with left main coronary artery disease.

Two hundred consecutive patients underwent myocardial revascularization for left main coronary artery disease between January, 1975, and December, 1981. The mean age of this group was 64 +/- 8 years, and 78.5% of the patients were men. The anginal pattern was chronic stable in 6% of the patients and progressive or unstable in the remainder. Resting electrocardiograms showed prior myocardial infarction in 45.5%. Left ventricular end-diastolic pressure was elevated in 145 patients, and ejection fraction was less than 50% in 40 patients. The mean number of bypass grafts per patient was 3.2 +/- 1.4 (standard deviation). Seventeen patients underwent major concomitant cardiovascular procedures. The operative mortality was 3.5%, and the incidence of perioperative infarction was 3%. Factors associated with reduced operative survival were increased age; unstable angina, or acute myocardial infarction, or both; female sex; circumflex-dominant circulation; and major concomitant procedures. Late mortality at a mean follow-up of 33.5 months was 6%, and 91% of the surviving patients assessed their quality of life as "excellent" or "good."

A study of uterine embryos recovered from rhesus monkeys fitted with intrauterine devices.

Fifteen mature female rhesus monkeys were mated and operated upon to recover preimplantation uterine embryos. This resulted in the recovery of 25 embryos or unfertilized ava in 43 attempts. The same animals were fitted with plastic intrauterine devices (IUDs) and the recovery procedure was repeated. In this series 61 recovery attempts yielded only 10 embryos, 7 of which were sectioned and analyzed by transmission electron microscopy. This approach revealed the ultrastructural details of embryo degeneration and leukocyte association seen in embryos recovered from IUD-bearing animals. Samples of peripheral venous blood were analyzed for levels of ovarian steroids at the time of embryo recovery. The results are discussed in relation to the mechanism of action of IUDs.

Fluctuations of the atrial cycle length and A-V delay with a universal (DDD) pacemaker.

The electronic characteristics of a new universal (DDD) pulse generator can result in significant shortening of the atrial cycle length (A-A interval) and shortening of the atrioventricular (A-V) interval beyond the programmed values. These pacemaker arrhythmias are entirely compatible with normal function and must not be interpreted as malfunctions.

Isolated chronic tricuspid insufficiency due to closed chest trauma: report of a case with long-term follow-up.

A case of isolated chronic tricuspid insufficiency due to closed chest trauma is described in this report. Studies for carcinoid syndrome were negative. At surgery the posterior leaflet of the tricuspid valve appeared to be torn and disrupted. The other leaflets were shortened and atrophic. The results of pre- and postoperative cardiac catheterization with long-term follow-up to the present, and the available literature on this rare entity has been briefly reviewed.

Safety and efficacy of internal mammary artery grafts for left main coronary artery disease. A preliminary report.

Questions regarding the relative safety and efficacy of internal mammary artery (IMA) grafts versus saphenous vein grafts (SVG) in patients with left main coronary artery disease (LMCAD) have not been specifically addressed in the literature. To elucidate this point, we analyzed 196 patients with LMCAD who underwent myocardial revascularization between January 1975 and December 1981, 98 by IMA and SVG and 98 by SVG, IMA was used most often to bypass the left anterior descending (LAD). Chi Square and "t" tests were performed on all demographic, cardiac and operative data comparing IMA to SVG. All results were non-significant, indicating that the two groups were comparable. Anginal pattern was progressive or unstable in 93%. IMA was used in 4 patients who were on intra-aortic balloon pump. The mean number bypass grafts per patient was 3.1. Postoperative complications were comparable for both groups, including early and late myocardial infarction. Overall operative mortality was 2.6%. Results of a survival analysis indicated no significant difference in the mortality rates of patients operated on by SVG versus IMA-SVG. Cumulative mortality rates at a mean followup of 20.5 months were 12.2% for SVG and 7.1% for IMA patients. Significant mortality risk factors were ejection fraction less than 55% (p less than 0.05); and perioperative myocardial infarction (p less than 0.001). Twenty-five patients with recurrent chest pain underwent repeat cardiac catheterization. This revealed 10 of 10 patent IMA grafts, 6 of 8 single patent SVG to LAD and 6 of 9 patent sequential vein grafts to the diagonal and LAD arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary bypass for left main disease in patients over 70 years of age.

Seventy-one consecutive patients over 70 years of age underwent isolated coronary bypass surgery for left main coronary artery (LMCA) disease between September 1975 and December 1982. All patients had angina; 6% were in NYHA functional class II, 30% class III, and 64% class IV. Intravenous nitroglycerin was required in 25% of patients. Resting electrocardiogram was abnormal in 91% of patients and stress testing performed in 24 patients was positive in all. Degree of left main stenosis graded by diameter was 60 to 70% in 24% of patients and greater than 70% in 76%. In addition to left main stenosis 66% of patients had significant triple vessel disease. Left ventricular end diastolic pressure (LVEDP) was elevated in 69% of patients while ejection fraction (EF) was low only 24%, without correlation between high LVEDP and low EF. Mean number of bypass grafts per patient was 3.4 +/- 0.6. Hospital mortality was 7% and mean post-operative stay was 10.4 +/- 2.0 days. Stepwise multiple regression analysis of 12 variables identified only unstable angina requiring intravenous nitroglycerin as a significant predictor of hospital mortality (p less than 0.01). Follow-up was complete with a late cardiac mortality of 4.5%. Seventy-five percent of surviving patients assessed their quality of life as good at a mean follow-up of 26 months. Coronary bypass for LMCA disease in a non-selected elderly population can be performed with low operative mortality and marked improvement in quality of life.

Advantages of superior approach for mitral valve surgery.

Technical factors in mitral valve surgery (MVS) which may influence neurological complications, trauma to the left atrium and formation of atrial mural thrombi have not previously been described in detail. We have reviewed the records of 146 patients (pts) undergoing MVS through the superior approach between January 1974 and May 1981. The series consisted of 97 females and 49 males with a mean age of 57 +/- 18 years. All but 4 pts were in New York Heart Association functional class III or IV. Twenty-five pts underwent open mitral commissurotomy, 116 had valve replacement and 5 had annuloplasty. Concomitant procedures were coronary bypass in 47, aortic valve replacement in 18 and resection of left ventricular aneurysm in 3. Left atrial thrombi were removed in 21 pts. Thirteen pts (9%) died postoperatively. The causes of death were left ventricular failure in 7, arrhythmia in 4 and atrio-ventricular disruption in 2. Two of these pts also had cerebral dysfunction. Autopsy examination in 8 pts failed to reveal formation of fresh left atrial septal or posterior mural thrombus. Postoperative complications included transient neurologic injury presumed to be due to air embolus in 3 and postoperative bleeding from atrial suture line in one. The mean follow-up for the survivors has been 30 months. There have been 16 (12%) late deaths from 1 to 72 months (mean 15). Autopsy examination of 4 pts and surgical exploration in one other pt which failed to reveal organized left atrial mural thrombus. Only one late death was related to prosthetic thrombosis. This occurred following cessation of anticoagulations.(ABSTRACT TRUNCATED AT 250 WORDS)

Extra-anatomic bypass operation for aorto-iliac disease in poor risk cardio-pulmonary patients.

Three years experience with subcutaneous axillo-femoral and bifemoral bypass surgical procedures has been outlined in patients with poor cardio-pulmonary and other risk related factors. Special emphasis has been made regarding technical consideration; advantages and disadvantages have been discussed. There were 49 limbs at risk in this group of 27 patients requiring axillo-bifemoral in 22, and axillo-unifemoral in 5. Sixty-three percent of patients had associated arteriosclerotic heart disease and 48% had severe emphysema. There were 3 peri-operative deaths for 11% hospital mortality and 3 late deaths (12.5%). Six of the remaining patients for whom long term follow-up is available, acute graft thrombosis occurred in 3 patients salvaged by graft thrombectomy and 4 patients had late thrombosis resulting in 3 permanent graft failures. Two patients required above the knee amputation. Limb salvage and relief of lower extremity ischemic pains has been gratifying. During the limited follow-up period from 1-36 months (Mean 18) there is 87% patency rate for 43 grafts to 43 limbs.