Surgical and Radiology Trainees' Proficiency in Reading Mammograms: the Importance of Education for Cancer Localisation.

Medical imaging with mammography plays a very important role in screening and diagnosis of breast cancer, Australia's most common female cancer. The visualisation of cancers on mammograms often forms a diagnosis and guidance for radiologists and breast surgeons, and education platforms that provide real cases in a simulated testing environment have been shown to improve observer performance for radiologists. This study reports on the performance of surgical and radiology trainees in locating breast cancers. An enriched test set of 20 mammography cases (6 cancer and 14 cancer free) was created, and 18 surgical trainees and 32 radiology trainees reviewed the cases via the Breast Screen Reader Assessment Strategy (BREAST) platform and marked any lesions identifiable. Further analysis of performance with high- and low-density cases was undertaken, and standard metrics including sensitivity and specificity. Radiology trainees performed significantly better than surgical trainees in terms of specificity (0.72 vs. 0.35; P < 0.01). No significant differences were observed between the surgical and radiology trainees in sensitivity or lesion sensitivity. Mixed results were obtained with participants regarding breast density, with higher density cases generally having lower performance. The higher specificity of the radiology trainees compared to the surgical trainees likely represents less exposure to negative mammography cases. The use of high-fidelity simulated self-test environments like BREAST is able to benchmark, understand and build strategies for improving cancer education in a safe environment, including identifying challenging scenarios like breast density for enhanced training.

The relationship of parthenogenesis in virgin Chinese Painted quail (Coturnix chinensis) hens with embryonic mortality and hatchability following mating.

Unfertilized chicken, turkey, and quail eggs are capable of developing embryos by parthenogenesis. However, it is unknown if the physiological mechanisms regulating parthenogenesis in virgin hens may actually work against fertilization, embryonic development, and hatchability of eggs from these same hens following mating. Additionally, because most parthenogenic development closely resembles early embryonic mortality in fertilized eggs during the first 2 to 3 d of incubation, it is possible that many unhatched eggs classified as containing early embryonic mortality may actually be unfertilized eggs that contain parthenogens. Therefore, the objective of this study was to examine the relationship of parthenogenesis before mating with embryonic development and hatchability characteristics after mating. Based upon their ability to produce unfertilized eggs that contain parthenogens, 372 virgin Chinese Painted quail hens were divided into 7 groups, according to their incidence of parthenogenesis: 0, 10, 20, 30, 40, 50, and greater than 50% parthenogenesis. Males were then placed with these hens so that fertility, embryonic mortality, and hatchability could be evaluated for each hen. Hatchability of eggs set, hatchability of fertile eggs, and late embryonic mortality declined dramatically as the incidence of parthenogenesis increased. On the other hand, early embryonic mortality increased as parthenogenesis increased. Fertility was not different across the 7 parthenogenesis hen groups, perhaps because unfertilized eggs that exhibited parthenogenesis resembled and were therefore classified as early embryonic mortality. In conclusion, virgin quail hens that exhibit parthenogenesis appear to have impaired embryonic development and hatchability following mating. Additional sperm-egg interaction and embryonic research is needed to determine if a large portion of the early embryonic mortality experienced by mated hens that exhibit parthenogenesis as virgin hens is in fact embryonic development in unfertilized eggs.

The relationship of incubational egg weight loss with parthenogenesis in Chinese Painted quail (Coturnix chinensis).

Parthenogenesis, embryonic development of an unfertilized egg, has been studied extensively in turkeys. Recently it has been revealed that parthenogenesis also occurs in Chinese Painted quail, and the percentage of eggs exhibiting parthenogenesis is negatively correlated with clutch sequence position. In broiler breeders, it has been reported that the first egg of a clutch sequence loses less egg weight during incubation than subsequent eggs. Because the incidence of parthenogenesis is greater and egg weight loss is less in the first egg of a clutch sequence, it is possible that egg weight loss is less in parthenogenetic eggs. Therefore, the objective of this study was to determine if a relationship exists between egg weight loss (a measure of eggshell quality) and parthenogenesis. Daily, individual eggs were collected and labeled. To determine egg weight loss, eggs were weighed before setting and then again after 10 d of incubation. Eggs were stored for 0 to 3 d at 20°C and incubated at 37.5°C. Pearson correlation coefficients were used to determine if relationships existed between egg weight loss and average incidence of parthenogenesis, parthenogen size, egg storage, and average clutch sequence position for all hens examined (157) as well as only for hens that exhibited parthenogenesis (102). The percentage of egg weight loss was negatively correlated with the incidence of parthenogenetic eggs and parthenogen size. However, the percentage of egg weight loss was positively correlated with average clutch position. In conclusion, it appears that eggshell quality possibly influences the incidence of parthenogenesis in Chinese Painted quail eggs because as the percentage of egg weight loss decreases, the incidence of parthenogenesis increases.

Disinfection of eggshells using ultraviolet light and hydrogen peroxide independently and in combination.

Poor hatchability can occur due to eggshell bacterial contamination, which can be decreased by UV light or H(2)O(2) alone. However, antimicrobial effects of these 2 treatments combined, as well as optimum length of UV exposure, are not known. Therefore, the objectives of this study were to determine the optimum length of UV exposure for maximum bacterial reduction and to determine if a greater bacterial reduction would occur using a combination of UV and H(2)O(2) compared with either treatment alone. The first experiment was conducted to determine the optimum length of UV exposure by exposing eggs to 4, 8, 16, and 32 min of UV. Three experiments were also conducted to determine what concentration of H(2)O(2) in combination with UV exposure would yield maximum bacterial reduction. For experiment 2, treatments consisted of a control and UV alone as well as 0, 1, 2, and 3% H(2)O(2) alone and in combination with UV for 8 min. In experiment 3, treatments consisted of a control, UV alone, 3% H(2)O(2) alone, as well as 0, 0.5, 1, 1.5, 2, 2.5, and 3% H(2)O(2) in combination with UV for 8 min. Experiment 4 used 10 treatments including a control and 1.5, 2, and 2.5% H(2)O(2) at UV exposure times of 2, 4, and 8 min for each H(2)O(2) concentration. Results indicated that every control eggshell contained bacteria, resulting in an average bacterial count of 4 log cfu/egg. Exposure to UV alone for 8 min yielded significant bacterial reductions without excessive egg heating. When administered independently, H(2)O(2) and UV each reduced eggshell bacterial counts by 2 log cfu/egg. The combination of 1.5% H(2)O(2) and UV for 8 min reduced bacterial counts by a maximum of 3 log cfu/egg, with only 35% of the eggs positive for bacteria. Because bacterial contamination was further reduced by using a combination of UV and H(2)O(2), it is possible that hatchability and chick quality of breeder eggs might be improved by such treatments.

Genetic selection increases parthenogenesis in Chinese painted quail (Coturnix chinensis).

Parthenogenesis, embryonic development of an unfertilized egg, occurs naturally in turkey, chicken, and quail species. In fact, parthenogenesis in turkeys and chickens can be increased by genetic selection. However, it is unknown if genetic selection for parthenogenesis is effective in quail or if selection for parthenogenesis affects egg production. Therefore, the objectives of this study were to determine if the incidence of parthenogenesis in quail could be increased by genetic selection and if selection for this trait affects egg production. To prevent fertilization, 1,090 females were caged separately from males at 4 wk of age and then caged individually at 6 wk of age to monitor egg production. Eggs were collected daily, labeled, and stored for 0 to 3 d. After 10 d of incubation, 20 unfertilized eggs from each hen were examined for the occurrence of parthenogenesis and embryonic growth. In the parent (P) generation and subsequent generations (1 to 4), hens laying eggs containing parthenogenetic development and males whose sisters or mothers exhibited parthenogenesis were used for breeding. There was a linear increase in the percentage of hens exhibiting parthenogenesis as generation of selection increased. With each successive generation, there was a quadratic response in the percentage of eggs positive for parthenogenesis. When compared with the P generation, parthenogenesis was almost 3 times greater for eggs laid by the fourth generation (4.6 to 12.5%, respectively). Even when only hens exhibiting parthenogenesis were examined, the percentage of eggs demonstrating embryonic development responded quadratically with generation of selection. The embryonic size at 10 d of incubation was greater for each subsequent generation when compared with the P generation. There was a linear decrease in both egg production and the average position of an egg in a clutch as generation of selection increased. In conclusion, genetic selection for parthenogenesis increased the incidence of parthenogenesis and embryonic size but decreased egg production and average position of an egg in a clutch as generations of selection increased.

Homecare marketing and product management.

Entirely too much lip service is paid to marketing and product management in the health sector with too little action. Home health to one degree or another is guilty of this. Successful home health organizations will capitalize on the power of traditional marketing and product management approaches. Product, pricing, packaging, position, and penetration may be foreign concepts. But marketing is built on these concepts and they are key to product definition and management.

Stiffness, force, and sarcomere shortening during a twitch in frog semitendinosus muscle bundles.

The time course of force and stiffness during a twitch was determined at 6 and 26 degrees C in frog semitendinosus muscle bundles using the transmission time technique of Schoenberg, M., J.B. Wells, and R.J. Podolsky, 1974, J. Gen. Physiol. 64:623-642. Sarcomere shortening due to series compliance was also measured using a laser light diffraction technique. Following stimulation, stiffness developed more rapidly than force, but had a slower time course than published Ca2+ transients determined from light signals using Ca2+ sensitive dyes (Baylor, S.M., W.K. Chandler, and M.W. Marshall, 1982, J. Physiol. (Lond.). 331:139-177). Stiffness (S) did not reach its tetanic value during a twitch at 6 or 26 degrees C, although at 6 degrees C, it approached close to this value with S-twitch/S-tetanus = 0.82 +/- 0.07 (+/- SEM). During relaxation, force fell more rapidly than stiffness both for a twitch and also a tetanus. Also in this paper, several of the assumptions inherent in using the transmission time technique for the measurement of stiffness are considered in detail.

Sodium ions as blocking agents and charge carriers in the potassium channel of the squid giant axon.

Instantaneous K channel current-voltage (I-V) relations were determined by using internally perfused squid axons. When K was the only internal cation, the I-V relation was linear for outward currents at membrane potentials up to +240 mV inside. With 25-200 mM Na plus 300 mM K in the internal solution, an N-shaped I-V curve was seen. Voltage-dependent blocking of the K channels by Na produces a region of negative slope in the I-V plot (F. Bezanilla and C. M. Armstrong. 1972. J. Gen Physiol, 60: 588). At higher voltages (greater than or equal to 160 mV) we observed a second region of increasing current and a decrease in the fraction of the K conductance blocked by Na. Internal tetraethylammonium (TEA) ions blocked currents over the whole voltage range. In a second series of experiments with K-free, Na-containing internal solutions, the I-V curve turned sharply upward about +160 mV. The current at high voltages increased with increasing internal Na concentration was largely blocked by internal TEA. These data suggest that the K channel becomes substantially more permeable to Na at high voltages. This change is apparently responsible for the relief, at high transmembrane voltages, of the blocking effect seen in axons perfused with Na plus K mixtures. Each time a Na ion passed through, vacating the blocking site, the channel would transiently allow K ions to pass through freely.

Muscle compliance and the longitudinal transmission of mechanical impulses.

The time required for a mechanical impulse to propagate from one end to the other was measured directly in frog sartorius muscles and in fiber bundles from the semitendinosus muscle. When the fibers were fully activated, the transmission velocity was 170 mm/ms. In resting fibers the transmission time was three to four times greater than in activated fibers. Control experiments indicated that the transmission time across the tendons was negligible. A muscle compliance of 55-80 A per half sarcomere was estimated from these data. The "measurement time" of the method was calculated to be about 15 micros. This relatively short measurement time makes the method potentially useful for detecting changes in cross-bridge compliance.