Efficacy of carbohydrate sources for milk production by cows fed diets based on alfalfa silage

The effectiveness of three carbohydrate sources, high-moisture ear corn (HMEC), cracked shelled corn (CSC), and a 50:50 mixture of HMEC plus dried citrus pulp (DCP), fed with or without supplemental rumen-undegraded protein as expeller soybean meal (ESBM), was assessed in 48 multiparous dairy cows. All diets contained (dry mater [DM] basis) 50% alfalfa silage, 10% ryegrass silage, 28% NDF, and one of six concentrates: A) 38% HMEC; B) 38% CSC; C) 19% DCP plus 19% HMEC; D) 27% HMEC plus 12% ESBM; E) 27% CSC plus 12% ESBM; or F) 13% DCP, 13% HMEC, and 12% ESBM. Diets A, B, and C averaged 19% crude protein, of which 53% was nonprotein nitrogen (NPN), and diets D, E, and F averaged 22% crude protein, of which 40% was NPN. Cows were fed a high-energy covariate diet for 2 wk, blocked into eight groups of six, based on covariate protein yield, then randomly assigned to diets that were fed for 12 wk. Feeding ESBM increased DM intake, yields of milk, fat-corrected milk, fat, protein, SNF, and milk and blood urea concentration and decreased weight loss. There were no production differences between HMEC and CSC. However, DM intake, yields of milk, fat-corrected milk, fat, protein, lactose, SNF, and milk SNF content all were lower on the diets containing DCP versus HMEC and CSC. A 6 x 6 Latin square trial conducted at the same time with six ruminally cannulated cows showed similar effects of diet on DM intake and milk production. Ruminal ammonia was elevated by ESBM but not ruminal total amino acids and branched-chain volatile fatty acids. Ruminal propionate was highest on HMEC diets and lowest on DCP diets; acetate, butyrate and acetate-to-propionate ratio were lowest on HMEC diets and highest on DCP diets. These results indicated that, compared to HMEC and CSC, feeding the pectin-rich carbohydrate source DCP altered ruminal fermentation but depressed intake and milk production in lactating cows.

Severe blunt renal trauma: a 7-year retrospective review from a provincial trauma centre

BACKGROUND

Renal trauma is reported in 3% of trauma patients. The majority (>90%) are due to blunt mechanisms of injury. Minor renal injuries pose few management difficulties and the majority are managed expectantly. More serious injuries are potentially life threatening and have been historically managed by operative intervention with repair of the injured kidney when possible. More recently, there has been a trend towards non-operative management of all solid intra-abdominal organ injury including renal trauma. The purpose of this study was to review a 7-year experience in renal trauma at a provincial trauma centre and to define management practices along with patient and organ outcomes in severe renal injury.

METHODS

The BC Trauma Registry was reviewed for all admissions from January 1, 1992 to December 31, 1998 to identify patients with renal injury. Patient charts were reviewed to determine sex, age, mechanism of injury, vitals, imaging, associated injuries, and management and outcomes. Renal injuries were graded according to the American Association for the Surgery of Trauma Grading System.

RESULTS

During the study period 16 250 consecutive trauma cases were seen at Vancouver General Hospital. Of these cases, 227 (1.4%) patients sustained renal injuries: blunt in 93.4% and penetrating in 6.6%. Among patients with blunt renal trauma, 18.3% were grade III, IV, or V injuries. In this population, nearly 80% had associated trauma and also 80% had gross hematuria. Management was conservative in 87.5% of grade III and 77.7% of grade IV; however, 90.9% of grade V injuries went immediately to the OR. Nephrectomy rates were: 12.5% (III), 16.6% (IV), and 90.9% (V) with an overall exploration rate of 7.1% for all blunt renal trauma. Blunt renal trauma patients experienced few genitourinary complications. Overall, 3 patients of 40 with grade III, IV or V injuries died due to cardiac arrest in the emergency room.

CONCLUSIONS

Blunt renal trauma managed conservatively is associated with few complications in the hemodynamically stable patient. Grade V injuries still result in a nephrectomy rate of 90.9% with hemodynamic instability the indication in 100% of patients.

H1-receptor antagonists: safety issues

Histamine is an important neurotransmitter. Old (first-generation) H1-receptor antagonists such as chlorpheniramine, diphenhydramine, or triprolidine produce histamine blockade at H1-receptors in the central nervous system (CNS) and frequently cause somnolence or other CNS adverse effects. New (second generation) H1-antagonists such as cetirizine, fexofenadine, and loratadine represent an advance in therapeutics; in manufacturers' recommended doses, they enter the CNS in smaller amounts, produce relatively little somnolence or other CNS adverse effects, and do not exacerbate the adverse CNS effects of alcohol or other CNS-active chemicals. Two H1-antagonists, astemizole and terfenadine, have been found to prolong the QTc interval and, rarely, to cause cardiac dysrhythmias after overdose or under other specific conditions. This has led to withdrawal of regulatory approval for them. An H1-antagonist absolutely free from adverse effects under all circumstances is not yet available for use.

Impact on process of trauma care delivery 1 year after the introduction of a trauma program in a provincial trauma center

BACKGROUND

Trauma care delivery in Canada, even in major trauma centers, usually devolves to the most involved service. For patients with multisystem injuries, this is not always optimal and aspects of care outside the domain of the primary service are apt to be overlooked. Trauma care is necessarily multidisciplinary, and to be optimal, appropriate integration of the care process and prioritization are required. The purpose of this study was to examine the impact on care in a busy provincial trauma center, after the introduction of a trauma program with a clinical trauma service, revised trauma protocols, and a dedicated trauma unit.

METHODS

Data were collected prospectively before and during the introduction of the program. Aspects of care studied included trauma patient volume, compliance with trauma team activation and trauma consultation protocols, delays to the operating room for hypotension or open fractures, delays in disposition to the unit, average length of stay, and mortality based on Trauma and Injury Severity Score analysis. Data are presented summarized by quarter, one before and four after the introduction of the program. Variance tracking was introduced before the last quarter. Differences between preprogram and postprogram performance were assessed by using analysis of variance (asterisks indicates p < 0.05 compared with preprogram performance).

RESULTS

Trauma unit average length of stay decreased from 10.15 days initially to 9.66 and 9.14* days at 6 and 12 months, reducing costs. Improved survival was demonstrated by Trauma and Injury Severity Score methodology with z score achieving significance compared with Major Trauma Outcome Study outcomes after program implementation.

CONCLUSION

Trauma care improvement can be achieved by a multidisciplinary team focusing on the process of care, developing a dedicated trauma service to manage the more seriously injured patients, collecting them onto a single unit, and initiating program management.

How risky is your company?

In boom times, it is easy for managers to forget about risk. And not just financial risk, but organizational and operational risk as well. Now there's the risk exposure calculator, a new tool that will help managers determine exactly where and how much internal risk is mounting in their companies. The risk calculator is divided into three parts: The first set of "keys" alerts managers to the pressures that come from growth. Now that the company has taken off, are employees feeling increased pressure to perform? Is the company's infrastructure becoming overloaded? And are more new employees coming on board as the company rushes to fill positions? If the answer is yes to any one of those questions, then risk may be rising to dangerous levels. The second set of keys on the calculator highlights pressures that arise from corporate culture. Are too many rewards being given for entrepreneurial risk taking? Are executives becoming so resistant to bad news that no one feels comfortable alerting them to problems? And is the company's level of internal competition so high that employees see promotion as a zero-sum game? The final set of pressures, the author says, revolves around information management. When calculating these pressures, managers should ask themselves, what was the company's complexity, volume, and velocity of information a year ago? Have they risen? By how much? How much of the time am I doing the work that a computer system should be doing? High pressure on many or all of these points should set off alarm bells for managers. To control risk, managers have four levers of control at their disposal that will show them where they need to make organizational adjustments.

Hypoxic syncope

INTRODUCTION

Syncope at altitude of otherwise healthy individuals is a well-known phenomenon (22). We report on the cardiovascular effects observed in subjects exposed to hypoxia to illustrate the role of the sympathetic-adrenergic system in hypoxic syncope. This study describes unexpected episodes of (near) syncope during two crossover trials at simulated altitude in a low pressure chamber.

METHODS

In study A, 30 healthy male volunteers underwent 4 exposures to short-term (20 min) acute severe hypoxia (20,000 ft or 6096 m) to assess psychological performance. In study B, five volunteers were studied during prolonged exposure (1 h) to moderate hypoxia (13,500 ft or 4115 m) with and without concomitant low dose infusion with atrial natriuretic peptide to investigate the effects on pulmonary gas exchange.

RESULTS

In study A (acute severe hypoxia), 6 out of 120 exposures (5%), in 5 subjects, were accompanied by lightheadedness, pallor, sweating, and bradycardia. Two subjects (2%) had syncope with cardiac asystole. In study B during moderate hypoxia without atrial natriuretic peptide, adverse reactions were absent and the (nor)epinephrine levels remained unchanged. Concomitant infusion with atrial natriuretic peptide resulted in near syncope (recumbent in 3, standing in 2) at an oxygen saturation of 82%. While the epinephrine level had eightfold increased, mean arterial pressure fell from 94 to 40 mm Hg and heart rate from 79 to 44 bpm. The norepinephrine level remained unchanged illustrating a dissociated sympathetic-adrenergic response. All subjects with syncope recovered spontaneously within few minutes in Trendelenburg's position with oxygen supplied. None suffered from prolonged side effects.

CONCLUSION

It is concluded that exposure to acute severe hypoxia is a sufficient cause for syncope in healthy individuals. Enhanced vasodilatation to epinephrine may contribute to the withdrawal of sympathetic and enhancement of parasympatic activity, leading to vascular collapse, bradycardia or asystole (Bezold-Jarisch reflex). Patients fully recover in Trendelenburg's position with supplemental oxygen and further clinical examinations are not necessary.

The ongoing challenge of retroperitoneal vascular injuries

BACKGROUND

Retroperitoneal vascular injury remains one of the most frequent causes of death following abdominal trauma. A risk analysis of the association between potential outcome predictors and mortality following abdominal aorta and inferior vena cava injuries was performed.

METHODS

Eighty-nine patients sustaining abdominal aortic or inferior vena cava injury were concurrently evaluated for a 10-year period and retrospectively reviewed. A multiple logistic regression model evaluated the following variables:presence of shock on admission, base deficit (< -10 or > or = -10), classification by the organ injury scale (OIS), blood transfusion, crystalloid infusion, total infusion volume, associated injuries, site of injury, and presence of retroperitoneal tamponade.

RESULTS

Overall mortality for all injuries was 57%. Excluding all death on arrival (DOA) patients, the mortality rate decreased to 45.7%. Death following abdominal aortic injuries was significantly associated with free bleeding in the peritoneal cavity, acidosis, and an injury in the suprarenal location (OIS > 4). For inferior vena cava injuries and combined abdominal aortic and inferior vena cava injuries, death was associated with free bleeding, the suprarenal location (OIS = 4), and the presence of shock on admission as well.

CONCLUSIONS

Despite advances in transport and resuscitation, mortality of aortic and vena cava injuries remains unchanged. Shock on admission, bleeding without retroperitoneal tamponade, acidosis, and the suprarenal location each play a significant role in mortality. Immediate identification associated with a rapid surgical approach are the only factors that may improve survival of such devastating injuries.

Atrial natriuretic peptide improves pulmonary gas exchange in subjects exposed to hypoxia

Atrial Natriuretic Peptide (ANP) is secreted in response to hypoxia and pulmonary vasoconstriction. The hormone modulates pulmonary vascular tone in vivo and decreases pulmonary edema in isolated lungs exposed to several toxic agents. In addition, ANP improves the barrier function of endothelial cell monolayers in vitro. The plasma levels of ANP are elevated in patients with high-altitude pulmonary edema. We hypothesized that under these circumstances, ANP improves pulmonary gas exchange by attenuating the transvascular permeation of plasma (water). Therefore, we studied the effect of low-dose ANP in 11 healthy mountaineers exposed to hypoxia in a single-blind, placebo-controlled, cross-over design. During four 1-h periods, the subjects were stepwise exposed to decreasing barometric pressure, with a minimum of 456 mm Hg (simulated altitude, 4,115 m). Infusion of 5 ng/kg/min human-ANP increased the plasma ANP concentrations approximately twofold. The plasma concentrations of cyclic GMP, which is the second messenger of ANP, rose approximately threefold. Infusion of ANP did not affect the hemodynamic or ventilatory response to hypoxia. The hemoglobin concentration, however, rose from 9.0 +/- 0.1 to 9.4 +/- 0.1 mmol/L (p < 0.01) during ANP infusion but not during placebo infusion. The change in plasma volume calculated from this hemoconcentration indicated that approximately 10% of the plasma volume had permeated into the interstitium. Despite the observed whole-body hemoconcentration, oxygen saturation was significantly higher during ANP infusion than during placebo infusion (84.7 +/- 1.7 versus 79.6 +/- 1.8%, p < 0.05), and the alveolar-arterial oxygen difference was significantly lower (3.5 +/- 0.7 versus 7.3 +/- 0.8 mm Hg, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

In-house board-certified surgeons improve outcome for severely injured patients: a comparison of two university centers

The benefit derived from in-house board-certified attending surgeons (IHBCS) staffing trauma centers has recently been questioned. We compared the outcomes and provider-related complications of patients with severe injuries who were treated at two university trauma centers, one with IHBCS, and one with PGY-4 or PGY-5 residents in house (RIH). The RIH center had a significantly longer resuscitation time (160 vs. 58.8 minutes; p < 0.01). Except in cases of vascular injury, the odds ratio of dying at the RIH institution was significantly greater in all groups when the variables of transport time, Revised Trauma Score, and ISS were controlled. Errors in judgment were significantly more likely to have been made at the RIH institution in all groups. It is concluded that the management and ultimate outcome are significantly improved when IHBCS are involved with the resuscitation and early care of specific cohorts of severely injured patients.

Splenic trauma, choice of management

Images

Recent advances in H1-receptor antagonist treatment

The second-generation H1-receptor antagonists terfenadine, astemizole, loratadine, and cetirizine are important first-line drugs for the relief of symptoms in patients with allergic rhinoconjunctivitis or chronic urticaria and may eventually supplant the potentially sedating first-generation H1-receptor antagonists in the treatment of these disorders. Terfenadine, astemizole, loratadine, and cetirizine produce an incidence of central nervous system and anticholinergic adverse effects similar to that produced by placebo. Our ability to use H1-receptor antagonists optimally has been greatly enhanced by recent pharmacokinetic and pharmacodynamic studies of these medications.

Single base substitution in codon 74 of the MD rat myelin proteolipid protein gene

The myelin-deficient (md) rat is one of several X-linked animal mutants that have severe dysmyelination in the central nervous system. It appears in all to be the result of mutations in the myelin proteolipid protein gene which is located on the long arm of the X-chromosome. To identify the md rat mutation, we isolated and sequenced cDNAs corresponding to PLP and DM-20 mRNAs from the brain of hemizygous affected males. The only consistent sequence difference between these and normal rat sequences was the substitution of a C for an A at the first position of codon 74, resulting in a threonine to proline amino acid change. The presence of this helix-breaking amino acid in the second hydrophobic alpha-helical segment of the protein might be expected to influence its ability to interact with the membrane. PCR amplification and sequencing of the corresponding genomic regions were used to confirm the presence of the single base change in the hemizygote and both normal and mutant versions in the heterozygotes. It is interesting that this change, like those detected in other X-linked myelin disorders, involves an amino acid replacement within a hydrophobic alpha-helical segment of the PLP protein. Disruption of these structures apparently has severe consequences for the ability of PLP to contribute normally to myelination.