Dietary sodium alters aldosterone's effect on renal sodium transporter expression and distal convoluted tubule remodelling

Aldosterone is responsible for maintaining volume and potassium homeostasis. Although high salt consumption should suppress aldosterone production, individuals with hyperaldosteronism lose this regulation, leading to a state of high aldosterone despite dietary sodium consumption. The present study examines the effects of elevated aldosterone, with or without high salt consumption, on the expression of key Na+ transporters and remodelling in the distal nephron. Epithelial sodium channel (ENaC) α-subunit expression was increased with aldosterone regardless of Na+ intake. However, ENaC β- and γ-subunits unexpectedly increased at both a transcript and protein level with aldosterone when high salt was present. Expression of total and phosphorylated Na+ Cl- cotransporter (NCC) significantly increased with aldosterone, in association with decreased blood [K+ ], but the addition of high salt markedly attenuated the aldosterone-dependent NCC increase, despite equally severe hypokalaemia. We hypothesized this was a result of differences in distal convoluted tubule length when salt was given with aldosterone. Imaging and measurement of the entire pNCC-positive tubule revealed that aldosterone alone caused a shortening of this segment, although the tubule had a larger cross-sectional diameter. This was not true when salt was given with aldosterone because the combination was associated with a lengthening of the tubule in addition to increased diameter, suggesting that differences in the pNCC-positive area are not responsible for differences in NCC expression. Together, our results suggest the actions of aldosterone, and the subsequent changes related to hypokalaemia, are altered in the presence of high dietary Na+ . KEY POINTS: Aldosterone regulates volume and potassium homeostasis through effects on transporters in the kidney; its production can be dysregulated, preventing its suppression by high dietary sodium intake. Here, we examined how chronic high sodium consumption affects aldosterone's regulation of sodium transporters in the distal nephron. Our results suggest that high sodium consumption with aldosterone is associated with increased expression of all three epithelial sodium channel subunits, rather than just the alpha subunit. Aldosterone and its associated decrease in blood [K+ ] lead to an increased expression of Na-Cl cotransporter (NCC); the addition of high sodium consumption with aldosterone partially attenuates this NCC expression, despite similarly low blood [K+ ]. Upstream kinase regulators and tubule remodelling do not explain these results.

The association between calf birth weight and the post-calving performance of its dairy dam in the absence of dystocia

The objective of the study was to quantify the association between the birth weight of a calf and subsequent performance of its dairy dam in the absence of any recorded calving assistance. A total of 11,592 lactation records from 4,549 spring-calving dairy cows were used. The association between a series of quantitative cow performance metrics (dependent variable) and calf birth weight (independent variable) was determined using linear mixed models; logistic regression was used where the dependent variable was binary. Nuisance factors in the models were calf sex, heterosis coefficient of both the cow and calf, dry period length immediately before the birth of the calf, cow age at calving relative to the median cow age per parity, breed proportion of the cow, cow live-weight between 100 and 200 d of lactation relative to the mean cow weight per parity, and contemporary group. Calf birth weight was included in the model as either a continuous or a categorical variable. Primiparous and multiparous cows were analyzed separately. Mean (SD) calf birth weight was 36.2 (6.8) kg. In primiparous cows, calf birth weight was associated with milk yield in the first 60 d of lactation, calving to first service interval, calving body weight (BW), and both nadir BW and body condition score (BCS). In multiparous cows, calf birth weight was associated with total milk, fat and protein yield in the first 60 and 305 d of lactation, peak milk yield, total milk solids, both calving and nadir BW, and BCS loss from calving to nadir. Relative to primiparous cows that gave birth to calves that were 34 - 37 kg (i.e., population mean), their contemporaries who gave birth to calves that were 15 - 29 kg produced 9.82 kg more milk in the first 60 d of lactation, had a 2-d shorter interval to first service, and were 8.08 kg and 5.51 kg lighter at calving and nadir BW, respectively; the former was also 0.05 units lower BCS (scale 1 [thin] to 5[fat]) at nadir. Relative to multiparous cows that gave birth to calves that were 34 - 37 kg birth weight, multiparous cows that gave birth to calves that were 15 - 29 kg yielded 59.63 kg, 2.44 kg and 1.76 kg less milk, fat and protein, respectively, in the first 60 d of lactation, produced 17.69 kg less milk solids throughout the 305-d lactation, and were also 10.49 kg lighter at nadir and lost 0.01 units more BCS to nadir. In a separate series of analyses, sire breed was added to the model as a fixed effect with and without calf birth weight. When calf birth weight was not adjusted for, 60-d milk yield for multiparous cows who gave birth to calves sired by a traditional beef breed (i.e., Angus, Hereford) produced 59.63 kg more than multiparous cows who gave birth to calves sired by a Holstein-Friesian. Hence, calf birth weight is associated with some subsequent dam performance measures albeit, where associations do exit, the effect is biologically small.

Re-assessing the importance of linear type traits in predicting genetic merit for survival in an aging Holstein-Friesian dairy cow population

The cumulative improvement achieved in the genetic merit for reproductive performance in dairy populations will likely improve dairy cow longevity; therefore, it is time to reassess whether linear type traits are still suitable predictors of survival in an aging dairy cow population. The objective of the present study was therefore to estimate the genetic correlations between linear type traits and survival from one parity to the next and, in doing so, evaluate if those genetic correlations change with advancing parity. After edits, 152,894 lactation survival records (first to ninth parity) were available from 52,447 Holstein-Friesian cows, along with linear type trait records from 52,121 Holstein-Friesian cows. A series of bivariate random regression models were used to estimate the genetic covariances between survival in different parities and each linear type trait. Heritability estimates for survival per parity ranged from 0.02 (SE = 0.004; first parity) to 0.05 (SE = 0.01; ninth parity). Pairwise genetic correlations between survival among different parities varied from 0.42 (first and ninth parity) to 1.00 (eighth to ninth parity), with the strength of these genetic correlations being inversely related to the interval between the compared parities. The genetic correlations between survival and the individual linear type traits varied across parities for 9 of the 20 linear type traits examined, but the correlations with only 3 of these linear type traits strengthened as the cows aged; these 3 traits were rear udder height, teat length, and udder depth. Given that linear type traits are frequently scored in first parity and are genetically correlated with survival in older parities, they may be suitable early predictors of survival, especially for later parity cows. Additionally, the direction of the genetic correlations between survival and rear udder height, teat length, and udder depth did not change between parities; hence, selection for survival in older parities using these linear type traits should not hinder genetic improvement for survival in younger parities.

Are subjectively scored linear type traits suitable predictors of the genetic merit for feed intake in grazing Holstein-Friesian dairy cows?

Measuring dry matter intake (DMI) in grazing dairy cows using currently available techniques is invasive, time consuming, and expensive. An alternative to directly measuring DMI for use in genetic evaluations is to identify a set of readily available animal features that can be used in a multitrait genetic evaluation for DMI. The objectives of the present study were thus to estimate the genetic correlations between readily available body-related linear type traits and DMI in grazing lactating Holstein-Friesian cows, but importantly also estimate the partial genetic correlations between these linear traits and DMI, after adjusting for differences in genetic merit for body weight. Also of interest was whether the predictive ability derived from the estimated genetic correlations materialized upon validation. After edits, a total of 8,055 test-day records of DMI, body weight, and milk yield from 1,331 Holstein-Friesian cows were available, as were chest width, body depth, and stature from 47,141 first lactation Holstein-Friesian cows. In addition to considering the routinely recorded linear type traits individually, novel composite traits were defined as the product of the linear type traits as an approximation of rumen volume. All linear type traits were moderately heritable, with heritability estimates ranging from 0.27 (standard error = 0.14) to 0.49 (standard error = 0.15); furthermore, all linear type traits were genetically correlated (0.29 to 0.63, standard error 0.14 to 0.12) with DMI. The genetic correlations between the individual linear type traits and DMI, when adjusted for genetic differences in body weight, varied from -0.51 (stature) to 0.48 (chest width). These genetic correlations between DMI and linear type traits suggest linear type traits may be useful predictors of DMI, even when body weight information is available. Nonetheless, estimated genetic merit of DMI derived from a multitrait genetic evaluation of linear type traits did not correlate strongly with actual DMI in a set of validation animals; the benefit was even less if body weight data were also available.

The Impact of Fellowship Training in Academic Plastic Surgery

BACKGROUND

The competitive nature of an academic plastic surgery career has contributed to an increase in sub-specialization. The aim of this study is to assess the benefits of subspecialty fellowship training to pursue a career in academic plastic surgery.

METHODS

A cross-sectional study was conducted of all current academic plastic surgeons (APSs) participating in Accreditation Council for Graduate Medical Education-certified residency programs. Online faculty website listings were used to collect their demographics, training and practice characteristics, academic rank and leadership positions, and research productivity.

RESULTS

A total of 927 APSs met the inclusion criteria, of which 70.2% had undergone fellowship training, with an overall significant increase in fellowship-trained surgeons within the last 10 years (odds ratio [OR], 1.66; P = 0.0005). Hand training was the most common fellowship (35.6%), followed by craniofacial (32.0%) and microsurgery (28.1%). Fellowship training was more prevalent among younger (48.7 vs 53.5 years, P < 0.0001), White (67.8%), and non-White (77.4%, P = 0.0058) APSs who had received either integrated (67.1%) or independent (81.8%, P < 0.0001) plastic surgery training and are currently working in a department (OR, 1.44; P = 0.028). Fellowship training was shown to influence academic rank (associate professor: OR, 1.68 [P = 0.0073]; full professor: OR, 0.58 [P = 0.0008]), leadership position (fellowship director OR, 10.09; P < 0.0001) and research productivity (publications: 26 vs 16.5; P = 0.0009). In addition, fellowship attainment did not correlate with the size of the employing academic program, population of the city of practice, or being a residency director or chair.

CONCLUSION

The majority of APSs have undergone fellowship training, and there is very strong evidence supporting its impact in current entry and advancement in academic plastic surgery.

Commercial beef farms excelling in terminal and maternal genetic merit generate more gross profit

Validation of beef total merit breeding indexes for improving performance and profitability has previously been undertaken at the individual animal level; however, no herd-level validation of beef genetic merit and profit has been previously investigated. The objective of the present study was to quantify the relationship between herd profitability and both herd-average terminal and maternal genetic merit across 1,311 commercial Irish beef herds. Herd-level physical and financial performance data were available from a financial benchmarking tool used by Irish farmers and their extension advisors. Animal genetic merit data originated from the Irish Cattle Breeding Federation who undertake the national beef and dairy genetic evaluations. Herd-average genetic merit variables included the terminal index of young animals, the maternal index of dams, and the terminal index of service sires. The herds represented three production systems: 1) cow-calf to beef, 2) cow-calf to weanling/yearling, and 3) weanling/yearling to beef. Associations between herd financial performance metrics and herd average genetic merit variables were quantified using a series of linear mixed models with year, production system, herd size, stocking rate, concentrate input, and the two-way interactions between production system and herd size, stocking rate, and concentrate input included as nuisance factors. Herd nested within the county of Ireland (n = 26) was included as a repeated effect. Herds with young cattle excelling in terminal index enjoyed greater gross and net profit per hectare (ha), per livestock unit (LU), and per kg net live-weight output. The change in gross profit per LU per unit change in the terminal index of young animals was €1.41 (SE = 0.23), while the respective regression coefficient for net profit per LU was €1.37 (SE = 0.30); the standard deviation of the terminal index is €37. Herd-average dam maternal index and sire terminal index were both independently positively associated with gross profit per ha and gross profit per LU. Each one unit increase in dam maternal index (standard deviation of €38) was associated with a €1.40 (SE = 0.48) and €0.76 (SE = 0.29) greater gross profit per ha and per LU, respectively. Results from the present study at the herd-level concur with previous validation studies at the individual animal level thus instilling further confidence among stakeholders as to the expected improvement in herd profitability with improving genetic merit.

The Changing Role of Nurses in Making Ethical Decisions

In past decades, biomedical technology has created such advances that many health care professionals and consumers are overwhelmed by the apparently unlimited choices in treatment decisions. Problems in human reproduction, preservation of life, research on human subjects, and allocation of scarce resources are just a few of the categories of concerns that we now face. These dilemmas are complex both from conceptual and ethical perspectives. Thus, it becomes more and more difficult to define such important concepts as “human life” or ‘extraordinary treatment,” and to apply these concepts to clinical situations. It has become almost impossible to objectively interpret and apply ethical principles which should guide actions of health care providers.

Genetic and nongenetic factors associated with lactation length in seasonal-calving, pasture-based dairy cows

Lactation yield estimates standardized to common lactation lengths of 270-d or 305-d equivalents are commonly used in management decision support tools and dairy cow genetic evaluations. The use of such measurements to quantify the (genetic) merit of individual cows fails to penalize cows that do not reach the standardized lactation length, or indeed reward cows that lactate for more than the standardized lactation length. The objective of the present study was to quantify the genetic and nongenetic factors associated with lactation length in seasonal-calving, pasture-based dairy cows. A total of 616,350 lactation length records from 285,598 Irish cows were used. Linear mixed models were used to quantify the associations between lactation length and calving month, parity, age at calving, previous dry period length, calving difficulty score, heterosis, recombination loss, breed, and herd size, as well as to estimate the genetic and residual variance components of lactation length. The median lactation length in the edited data set was 288 d, with 27% of cows achieving lactations of at least 305 d. Relative to cows calving in January, the lactations of cow calving in February, March, or April was, on average, 4.2, 12.7, and 21.9 d shorter, respectively. The lactation length of a first parity cow was, on average, 7.8, 8.6, and 8.4 d shorter than that of second, third, and fourth parity cows, respectively. Norwegian Red and Montbéliarde cows had, on average, a 4.7- and 1.6-d shorter lactation than Holstein-Friesian cows, respectively. The heritability estimate, coefficient of genetic variation, and repeatability estimate of lactation length were 0.02, 1.2%, and 0.04, respectively. Based on the genetic standard deviation for lactation length estimated in the present study (3.3 d), cows ranked in the top 20% for genetic merit for lactation length would be expected to have lactations 9.2 d longer than cows in the bottom 20%, demonstrating exploitable genetic variability. Given the vast array of genetic and nongenetic factors associated with lactation length, an approach which combines improved management practices and selective breeding may be an efficient and effective strategy to lengthen lactations.

An educational intervention for advance directives

In spite of the passage of the Patient Self-Determination Act in 1991, research indicates that providing information alone has not brought about a significant increase in the completion rates of advance directive (AD) documents. The purpose of this pilot study was to design, implement, and evaluate an interactive multimedia CD-ROM educational program on AD. Study subjects consisted of 31 volunteer elderly men and women in a senior citizens center. An interactive multimedia CD-ROM program was developed in phase I of the study. Subjects were administered on-line pretests and posttests. The effectiveness of the CD-ROM intervention was measured by AD attitude and knowledge changes. A program satisfaction scale was used, and an observer rated the subjects' use of the computer program. Subjects had a statistically significant change in posttest knowledge scores and a high degree of satisfaction and ease in using the computer program. The use of an interactive multimedia CD-ROM program with a touch-sensitive monitor to operate a computer-based AD program for senior citizens shows future promise.

Clinical judgment: an integrated model

Literature on clinical judgment is discussed as a background for proposing an integrated model of diagnostic-therapeutic and ethical reasoning. Information processing and nursing process components related to problem identification and problem solving serve as a framework for the integration of the two domains of clinical reasoning. Discussion focuses on the integration of process components, identification of areas of research, and the use of the model in education and practice.

Dose-related cutaneous toxicities with etoposide

BACKGROUND

Cutaneous toxicities are seen frequently in association with administration of high doses, but not standard doses, of agents. With the increasing use of etoposide in dose-intensive regimens, cutaneous toxicities are appearing with increasing frequency.

METHODS

A retrospective analysis of 145 patients treated with various doses of etoposide was conducted.

RESULTS

This analysis revealed a statistically significant increase in the frequency of these toxicities at doses of 2400 mg/m2 and 4200 mg/m2, compared with doses of 1800 mg/m2. Intense, painful palmar erythema accompanied by bullae formation and desquamation occurred at the 4200 mg/m2 dose. Symptoms were controlled by a short course of corticosteroids.

CONCLUSION

Although they are not dose limiting, substantial dose-related skin toxicities can be an important side effect of high-dose etoposide therapy.

Encephalopathy and seizures induced by intravesical alum irrigations

Hemorrhagic cystitis is a significant toxic effect of cyclophosphamide therapy. Continuous bladder irrigation of a 1% alum solution is a simple and generally safe method of chemical cautery to treat the bleeding urothelium. We report four cases of encephalopathy coincident with elevated aluminum levels as well as one patient who developed seizures while receiving continuous bladder irrigations with alum. All patients had significant renal insufficiency. We recommend the cautious use of alum irrigation in patients with renal impairment and monitoring of serum aluminum levels to prevent excessive accumulation and toxicity.

Generalized seizures secondary to high-dose busulfan therapy

Two patients without prior histories of neurologic disorders experienced generalized seizures while receiving high-dose busulfan (total dose 16 mg/kg) as part of a preparative regimen for allogeneic bone marrow transplantation. A review of the literature revealed 14 similar occurrences. Maintenance of therapeutic blood concentrations of phenytoin in subsequent patients at our institution has resulted in no further patients experiencing generalized seizures. Prophylactic anticonvulsant therapy should be considered in patients receiving high doses of busulfan.

The small pin circular fixator for distal tibial pilon fractures with soft tissue compromise

A Monticelli-Spinelli small pin circular external fixator was used in combination with closed reduction or a limited open reduction internal fixation in five cases in an attempt to salvage a satisfactory result in distal tibia pilon fractures when associated soft tissue compromise prevented standard fixation with plates and screws. The small pin fixator enhances the ability to perform a closed reduction through a technique that uses distraction with pins in the tibia and calcaneus, combined with correction of angulation by tensioning wires with a stop nut. Small pin stabilization of these comminuted fractures allows early patient mobilization. The small diameter pins support the soft cancellous bone fragments. This technique attempts to combine the benefits of traction, external fixation, and limited internal fixation. We recommend this technique as a salvage procedure when plates and screws are contraindicated because of poor bone and soft tissue conditions.

The small pin circular fixator for proximal tibial fractures with soft tissue compromise

We used a Monticelli-Spinelli small pin circular external fixator in five cases, in combination with closed reduction or limited open reduction internal fixation, to salvage a satisfactory result in juxtaarticular, intraarticular fractures of the proximal tibia, when associated soft tissue compromise prevented standard fixation with plates and screws. The small pin circular fixator allows juxtaarticular placement of the small pins, enhancing stabilization of the comminuted fractures, allowing early range of motion of the joint and early patient mobilization. The small diameter pins support the soft cancellous bone fragments. This technique attempts to combine the benefits of traction, external fixation, and limited internal fixation. We recommend this method as a salvage procedure when plates and screws are contraindicated because of poor bone and soft tissue conditions.

Stabilization of sacroiliac joint disruption with threaded compression rods

Eleven cases of sacroiliac dislocation and/or fracture (Malgaigne pattern) were successfully reduced and stabilized using two threaded compression rods. The mean follow-up period was 26.1 months (range, seven to 45 months). None of the implants failed and there was no subsequent displacement. Two patients had mild residual lower back pain, and one was treated with implant removal without subsequent relief of pain. One patient, in whom the operation was done 110 days after dislocation, had extension of an incomplete preoperative peroneal nerve palsy. After anterior pelvic ring stabilization has been performed, two threaded 3/16-inch diameter rods are driven from the normal posterior iliac wing superficial to the sacrum and through the reduced opposite iliac wing. Compression is obtained with washers and nuts. This procedure can be performed safely and effectively, providing stable fixation and allowing early mobilization to help lessen or prevent the complications associated with prolonged bed rest.

Complex femur fractures: treatment with the Wagner external fixation device or the Grosse-Kempf interlocking nail

One hundred complex femur fractures were treated with the Grosse-Kempf interlocking nail and 35 were treated with the Wagner external fixation device. Retrospectively, we analyzed the results in the two groups to determine specific indications for the future use of these nails. The Grosse-Kempf nail, although a technically demanding procedure, achieved excellent overall end results in comminuted closed fractures, and in Type I, Type II, and some Type III open fractures after appropriate wound care. We found that the Wagner apparatus was a simple, easy device for obtaining initial fracture stabilization in contaminated Type III-B and Type III-C open fractures. It does, however, require substantial postoperative care; four cases required secondary intramedullary fixation. We found a high infection rate with secondary reamed intramedullary nailing after initial stabilization with the external fixator.

Management of the upper extremity in traumatic tetraplegia

The management of the upper extremity in traumatic tetraplegia is complex and extremely important for the rehabilitation of the patient. The evolution of present management is reviewed. The evaluation and classification of the tetraplegic patient is discussed with general recommendations for treatment.

Cost of implementing Veterans Administration directives for handling antineoplastic agents

Directives issued by the Veterans Administration central office for the safe handling of antineoplastic agents are described, and the costs associated with implementing these directives are reported. The directives are similar to other recent guidelines, including those issued by the Occupational Safety and Health Administration. Inventory records for a 12-month period were analyzed to determine the total number of doses of antineoplastic agents prepared and the total number of treatments administered at a 704-bed VA facility with a comprehensive cancer treatment program. For 3112 prepared doses and 2345 treatment regimens, the total cost of implementing the directives was $57,115, including $6,670 for the purchase of a vertical laminar-airflow hood. The VA central office directives represent reasonable guidelines for controlling the potential hazards of handling antineoplastic agents. Considerable expense is associated with implementing the directives; the degree of added expense will vary based on the particular hospital setting, the number of doses of antineoplastic agents administered, and the nature of the oncology services already in place.

Jejunal rupture in a football player

An 18-year-old football player sustained a jejunal rupture when he was struck in the abdomen during a high school football game. Such abdominal injuries in contact sports are rare; however, it is imperative that team physicians, trainers, and coaches be aware of such injuries.

Dural puncture using the lateral approach for chemonucleolysis

The lateral approach for chemonucleolysis was developed to avoid dural puncture, which occurs with midline and posterolateral approaches. It is important to check for dural punctures during the procedure. If the dura is penetrated, a potential pathway is created for chymopapain to enter the subarachnoid space. Large doses of intrathecal chymopapain are highly toxic and small doses show a variable response. Because of the potential disastrous complications associated with intrathecal chymopapain, the chymopapain injection is contraindicated in the presence of a dural leak.