Hepatic artery pseudoaneurysm rupture: A case report

Hepatic artery pseudoaneurysms are an uncommon complication of blunt hepatic trauma typically presenting in a delayed fashion. A 40-year-old male presented to a trauma centre after a 6-metre fall from a construction site with multiple injuries including a grade IV liver laceration centred around the porta hepatis. This liver injury was managed non-operatively. On day sixteen of admission, he had a sudden cardiac arrest from haemorrhagic shock with a subsequent CT demonstrating a ruptured extrahepatic proper hepatic artery pseudoaneurysm. Despite laparotomy and vessel repair, he died from pulmonary complications of aspiration pneumonia and acute lung injury associated with massive transfusion. The literature demonstrates conflicting views regarding the utility of repeat CT to detect a pseudoaneurysm in asymptomatic, non-operatively managed patients with blunt hepatic trauma. In particular, the literature does not distinguish the utility of repeat routine CT for intrahepatic and extrahepatic hepatic artery pseudoaneurysm, the latter if which is rarer. Current guidelines recommend against it, but there are observational studies suggesting utility, particularly in high grade (≥IV) liver injury. In patients with a high-grade injury extending to the porta hepatis, repeat imaging should be considered to detect possible pseudoaneurysm.

Risk factors for breast cancer-related lymphedema in patients undergoing 3 years of prospective surveillance with intervention

Background

To evaluate risk factors (treatment‐related, comorbidities, and lifestyle) for breast cancer–related lymphedema (BCRL) within the context of a Prospective Surveillance and Early Intervention (PSEI) model of care for subclinical BCRL.

Methods

The parent randomized clinical trial assigned patients newly diagnosed with breast cancer to PSEI with either bioimpedance spectroscopy (BIS) or tape measurement (TM). Surgical, systemic and radiation treatments, comorbidities, and lifestyle factors were recorded. Detection of subclinical BCRL (change from baseline of either BIS L‐Dex ≥6.5 or tape volume ≥ 5% and < 10%) triggered an intervention with compression therapy. Volume change from baseline ≥10% indicated progression to chronic lymphedema and need for complex decongestive physiotherapy. In this secondary analysis, multinomial logistic regressions including main and interaction effects of the study group and risk factors were used to test for factor associations with outcomes (no lymphedema, subclinical lymphedema, progression to chronic lymphedema after intervention, progression to chronic lymphedema without intervention). Post hoc tests of significant interaction effects were conducted using Bonferroni‐corrected alphas of .008; otherwise, an alpha of .05 was used for statistical significance.

Results

The sample (n = 918; TM = 457; BIS = 461) was female with a median age of 58.4 years. Factors associated with BCRL risk included axillary lymph node dissection (ALND) (p < .001), taxane‐based chemotherapy (p < .001), regional nodal irradiation (RNI) (p ≤ .001), body mass index >30 (p = .002), and rurality (p = .037). Mastectomy, age, hypertension, diabetes, seroma, smoking, and air travel were not associated with BCRL risk.

Conclusions

Within the context of 3 years of PSEI for subclinical lymphedema, variables of ALND, taxane‐based chemotherapy, RNI, body mass index >30, and rurality increased risk.

The Prospective Surveillance and Early Intervention Model promotes identification and treatment of subclinical lymphedema, facilitating prevention of chronic lymphedema and risk reduction. Axillary lymph node dissection, taxane‐based chemotherapy, regional nodal irradiation, body mass index >30, and rurality are critical risk factors within the context of the Prospective Surveillance and Early Intervention Model for some patients.

Blunt thoracic aortic injury resulting in free rupture into the pleural space and cardiac arrest, managed successfully with endovascular stenting

Blunt thoracic aortic injury (BTAI) is an uncommon yet serious diagnosis in trauma patients, with high on-scene mortality. BTAI typically occurs from rapid deceleration such as in motor vehicle collisions or high-altitude falls shearing the aorta just proximal to the ligamentum arteriosum. We report a case of a man in his 50s falling from a height of 15 m who presented hypotensive with retrosternal chest pain. Mobile chest X-ray showed a widened mediastinum with left-sided haemothorax. CT revealed a contained free aortic rupture just inferior to the origin of the left subclavian artery with bleeding into the mediastinum and left pleural space. The patient underwent urgent thoracic endovascular aortic repair (TEVAR) but arrested on-table due to a left-sided tension haemothorax requiring chest-drain decompression and haemostatic resuscitation. After return of spontaneous circulation, TEVAR was successfully performed. BTAI is a dynamic process; hence, timely imaging and minimally invasive surgical treatment are key to patients surviving grade III and IV aortic injuries.

Utility of venous blood gases for the assessment of traumatic shock: a prospective observational study

BACKGROUND

ABG samples are often obtained in trauma patients to assess shock severity. Venous blood gas (VBG) sampling, which is less invasive, has been widely used to assess other forms of shock. The study aim was to determine the agreement between VBG and ABG measurements in trauma.

METHODS

Patients were enrolled at an Australian trauma centre between October 2016 and October 2018. Bland-Altman limits of agreement (LOA) between paired blood gas samples taken <30 min apart were used to quantify the extent of agreement. The impact of using only VBG measurements was considered using an a priori plan. Cases where venous sampling failed to detect 'concerning levels' were flagged using evidence-based cut-offs: pH ≤7.2, base deficit (BD) ≤-6, bicarbonate <21 and lactate ≥4. Case summaries of these patients were assessed by independent trauma clinicians as to whether an ABG would change expected management.

RESULTS

During the study period 176 major trauma patients had valid paired blood gas samples available for analysis. The median time difference between paired measurements was 11 min (IQR 6-17). There was a predominance of men (81.8%) and blunt trauma (92.0%). Median Injury Severity Score was 13 (range 1-75) and inpatient mortality was 6.3%. Mean difference (ABG-VBG) and LOA between paired arterial and venous measurements were 0.036 (LOA -0.048 to 0.120) for pH, -1.27 mmol/L (LOA -4.35 to 1.81) for BD, -0.64 mmol/L (LOA -1.86 to 0.57) for lactate and -1.97 mmol/L (LOA -5.49 to 1.55) for bicarbonate. Independent assessment of the VBG 'false negative' cases (n=20) suggested an ABG would change circulatory management in two cases.

CONCLUSIONS

In trauma patients VBG and ABG parameters displayed suboptimal agreement. However, in cases flagged as VBG 'false negative' independent review indicated that the availability of an ABG was unlikely to change management.

The Road to Survival for Haemodynamically Unstable Patients With Open Pelvic Fractures

Management of haemodynamically unstable pelvic ring injuries has been simplified into treatment algorithms to streamline care and emergent decision making in order to improve patient outcomes whilst decreasing mortality and morbidity. Pelvic ring injuries are most commonly a result of high-velocity and energy forces that exert trauma to the pelvic bones causing not only damage to the bone but the surrounding soft-tissue, organs, and other structures and are usually accompanied by injuries to other parts of the body resulting in a polytraumatised patient. Open pelvic fractures are a rare subset of pelvic ring fractures that are on the more severe end of the pelvic fracture continuum and usually produce uncontrolled haemorrhage from fractured bone, retroperitoneal haematomas, intraabdominal bleeding from bowel injury, soft tissue injuries to the anus, perineum, and genitals, fractures of the pelvic bones, causing bleeding from cancellous bone, venous, and arterial injuries combined with bleeding from concomitant injuries. This is a very complex and challenging clinical situation and timely and appropriate decisions and action are paramount for a positive outcome. Consequently, open pelvic fractures have an extremely high rate of mortality and morbidity and outcomes remain poor, despite evidence-based improvements in treatment, knowledge, and identification of haemorrhage; in the pre-hospital, critical care, and operative settings. In the future utilisation of haemostatic drugs, dressings, devices, and procedures may aid in the time to haemorrhage control.

The swing shift: Opportunity to enhance trauma training in Australia

BACKGROUND

Training in trauma forms a fundamental component of general surgical training in Australia. It faces a number of challenges, including the limitations of working hours and increasing use of non-operative management techniques. Adjustment of rosters to encompass a "swing shift" (12pm-midnight) is one proposed solution to maximise exposure of junior surgical doctors to trauma. This proposal prompted a review of the timing of major trauma presentations and interventions at a Level 1 trauma centre.

METHODS

A retrospective observational study was performed of all major trauma presentations to Westmead Hospital, Australia over ten-years (2008-2017). Trauma operative procedures and major resuscitations were reviewed across three potential shifts: day shift (0730-1930), night shift (1930-0730) and "swing shift" (1200-midnight). Operative interventions included: laparotomy, thoracotomy/sternotomy, re-look laparotomy, rib fixation and tracheostomy. Descriptive statistics were obtained for between-shift comparisons.

RESULTS

Over the ten-years there were 3745 full trauma team activations (FTTAs). The "swing shift" had the highest number of FTTAs, patients with injury severity scores >15, patients requiring resuscitation and emergency operations (laparotomies, sternotomies/thoracotomies).

CONCLUSIONS

More major trauma calls, laparotomies and thoracotomies occurred during a theoretical "swing shift" rather than the standard day and night shifts. Changing trauma rostering for junior doctors to reflect this peak in clinical and operative demand could change exposure to trauma training.

Donor white blood cell survival and cytokine profiles following red blood cell transfusion in Australian major trauma patients

BACKGROUND

The potential for the co-existence of genetically disparate cells (microchimerism) and associated cytokine profiles following red blood cell (RBC) transfusion in trauma patients has not been well characterized to date. This study investigated the incidence of surviving donor white blood cells (known as transfused-associated microchimerism (TAM)) and cytokine changes following blood transfusion in trauma patients.

STUDY DESIGN AND METHODS

Trauma patients with an injury severity score (ISS) >12 who had been transfused between 2012-2016 with at least 5 units of RBC units over a 4 h period were recruited. Trauma patients with ISS > 12 who did not require blood transfusion were recruited as controls. The incidence of TAM was determined using a panel of insertion/deletion (InDel) bi-allelic polymorphisms. Selected pro- and anti-inflammatory cytokine profiles were analyzed using cytometric bead array.

RESULTS

The transfused cohort (n = 40) had median ISS of 28 [12-66], received a median of 11 RBC units [4-114] and had median hospital length of stay of 35 days [1-152]. Only 11 (27.5%) patients returned for follow-up blood sampling after discharge. Of these, one patient showed an InDel pattern indicating the presence of TAM. No patients in the control cohort (n = 49) showed TAM. Cytokines IL-10 and IL-6 were found to be elevated in the transfused trauma patients.

CONCLUSION

In this cohort, TAM was found to occur in one patient of the 11 who received a blood transfusion. Elevated IL-6 and IL-10 cytokines were detected in those patients who were transfused. However, the incidence of TAM could not be correlated with the elevated cytokine profiles for this cohort.

Traumatic colonic injuries in Westmead Hospital – A paradigm shift in management over 10 years

Methods

Patients were identified via the prospectively collected trauma registry at Westmead Hospital from 2003 to 2013. Fifty-seven patients initially identified with a proven diagnosis of penetrating colonic injury had their medical records reviewed. Excluded in the study are patients who had rectal injuries or serosal tears of the colon. Patient characteristics, mechanisms of injury, treatment course and complications were analysed. Extent of colonic injury was graded of using American Association for the Surgery of Trauma scalings.

Results

A total of 55 patients were then included in the study. Primary repair of colon injuries was the most common method used (63.6%, n = 35) followed by resection and primary anastomosis (21.8% n = 12), diverting colostomy (14.3%, n = 5) and non-operative management (5.5%, n = 3). There was a higher rate of diversion in the earlier time period (2003–2007) when compared to the later time period (2008–2013), p = 0.03. Over the 10-year period, there was no significant difference with regards to complications among groups, particularly intra-abdominal complications.

Conclusion

From 2003 to 2013, there is a shift of management of penetrating colonic injuries from diversion to resection and primary anastomosis to that of primary repair. Primary repair of colonic injuries is a safe option and is associated with low morbidity. It should be considered as a valid tool in the armamentarium of today’s surgeon.

Leukodepleted blood components do not remove the potential for long-term transfusion-associated microchimerism in Australian major trauma patients

Despite the introduction of leukodepleted blood components, it has been shown that donor leukocyte engraftment (microchimerism) remains a long-term consequence of red blood cell (RBC) transfusion. The incidence of microchimerism may be affected by international disparities in blood processing methods or variations in transfusion practices. This study was conducted to determine the prevalence of microchimerism in Australian trauma patients. A secondary aim was to examine whether any patient complications correlated to the incidence of microchimerism. Australian trauma patients (n = 86) who had been transfused with red blood cell (RBC) units between 2000 and 2012 with an injury severity score (ISS) of greater than 15 were recruited. The prevalence of microchimerism was determined using genetic screening with a panel of insertion/deletion biallelic polymorphisms. The mean storage age of the transfused RBC units was 20 ± 8 days and the mean length of stay (LOS) in hospital was 40 ± 39 days. There were no significant associations in this study sample to bias for patient age, gender, number of transfused RBC units or ISS. Nine of the 55 (16.3%) patients transfused with non-leukodepleted blood components displayed an incidence of microchimerism. Of the 31 patients transfused with leukodepleted RBC units, 3 (9.6%) displayed an incidence of microchimerism. Therefore, despite the universal introduction of leukodepleted blood components in Australia, the prevalence of transfusion-associated microchimerism was found to be unchanged. Furthermore, half of the patients exhibiting microchimerism were recorded to have had splenic injury or required splenectomy at the time of transfusion.

Damage control in the injured patient

The damage control concept is an essential component in the management of severely injured patients. The principles in sequence are as follows: (1) abbreviated surgical procedures limited to haemorrhage and contamination control; (2) correction of physiological derangements; (3) definitive surgical procedures. Although originally described in the management of major abdominal injuries, the concept has been extended to include thoracic, vascular, orthopedic, and neurosurgical procedures, as well as anesthesia and resuscitative strategies.

The accuracy of focused assessment with sonography in trauma (FAST) in blunt trauma patients: experience of an Australian major trauma service

Focused assessment with sonography for trauma (FAST) is a method for detecting haemoperitoneum in trauma patients on initial assessment in the Emergency Department. The aim of this paper is to present an Australian trauma centre's experience with FAST as a tool to screen for intraabdominal free fluid in patient's sustaining blunt truncal trauma.

METHOD

Over a 63-month period, FAST scans were prospectively studied and compared with findings from a gold-standard investigation, either computed tomography (CT) or laparotomy.

RESULTS

463 FAST results were collected prospectively from 463 patients. 53 scans were excluded due to lack of a corresponding confirmatory gold-standard test. Overall sensitivity, specificity, positive and negative predictive values for FAST in detecting free fluid were 78%, 97%, 91%, 93%, respectively. Analysis of the credentialed operators demonstrated an improvement in accuracy (sensitivity 80%, specificity 100%, positive predictive value 100%, negative predictive value 94%). These findings are comparable with documented international experience.

CONCLUSION

The study demonstrates that the use of non-radiologist performed FAST in the detection of free fluid is safe and accurate within an Australian Trauma Centre.

The effect of dietary docosahexaenoic acid on the expression of porcine lipid metabolism-related genes1

To study the effect of dietary docosahexaenoic acid (DHA) on the expression of adipocyte determination and differentiation-dependent factor 1 (ADD1) mRNA in pig tissues, weaned, crossbred pigs (30 d of age) were fed either 2% (as-fed basis) tallow or DHA oil for 18 d. Body weight of the pigs was not affected by different dietary fatty acid (FA) compositions. The plasma and liver FA composition reflected the composition of the diet. The adipose tissue and skeletal muscle FA composition only partially reflected the diet, indicating either a slower FA turnover or that a greater proportion of the FA in these tissues is from endogenous FA synthesis. The ADD1 is an important transcription factor that modulates transcription of FA synthase to regulate the endogenous FA synthesis in the liver and adipose tissue. The ADD1 mRNA was decreased (P < 0.05) in the liver of DHA-treated pigs compared with that of the tallow-treated pigs. The diets did not have an effect on the ADD1 mRNA in pig adipose tissue. The ADD1 transcript was not detected in pig skeletal muscle. These results indicate that significant enrichment of liver DHA content inhibits the expression of ADD1 mRNA. Such an effect is similar to that reported in porcine differentiating adipocytes cultured with DHA. The liver and muscle acyl CoA oxidase mRNA concentration was increased (P < 0.05) by DHA oil treatment, suggesting that DHA treatment may increase peroxisomal fatty acid oxidation in these two tissues. Our present observations demonstrate that dietary DHA enrichment not only affects tissue DHA concentration but also mildly modifies the expression of genes related to fatty acid metabolism in the porcine liver and skeletal muscle.

Effect of polyunsaturated fatty acids on the expression of transcription factor adipocyte determination and differentiation-dependent factor 1 and of lipogenic and fatty acid oxidation enzymes in porcine differentiating adipocytes

Polyunsaturated fatty acids (FA) regulate genes involved in lipid metabolism. The effects of polyunsaturated FA on the transcription factor adipocyte determination and differentiation-dependent factor (ADD) 1 and fatty acid synthase (FAS) mRNA in differentiating porcine adipocytes were measured using a stromal vascular cell culture system. Porcine stromal vascular cells were isolated from subcutaneous adipose tissues and plated in Dulbecco's modified Eagle's medium (DMEM)-nutrient mixture F-12 Ham (F-12) plus fetal bovine serum (100 ml/l) for 24 h. Then cells were differentiated in DMEM-F12 plus insulin, hydrocortisone and transferrin without or with polyunsaturated FA at 6.25, 25.00 or 100.00 microM. The ADD1 mRNA was decreased by 100.00 microM-arachidonic acid, 6.25 to 100.00 microM-docosahexaenoic acid or cis-9,trans-11-conjugated linoleic acid. The polyunsaturated FA reduced the transcription rate of FAS, but not of ADD1. All three polyunsaturated FA accelerated degradation of ADD1 and FAS mRNA to reduce the abundance of ADD1 and FAS mRNA. Results also showed that polyunsaturated FA inhibit the ADD1 expression, not only of mRNA concentration, but also of mature ADD1 protein concentration, suggesting an overall reduction of ADD1 function by polyunsaturated FA. Our present experiments demonstrate that polyunsaturated FA regulate the gene expression of ADD1 and enzymes involved in lipid metabolism in porcine adipocytes.

Thoracolumbar fracture in blunt trauma patients: guidelines for diagnosis and imaging

OBJECTIVE

The aim of the study was to determine a clinical diagnostic pathway for the imaging of the thoracolumbar spine in blunt trauma patients.

METHOD

A literature review was undertaken to determine the factors important in the detection of thoracolumbar injury and also to produce a trial protocol, which could be tested retrospectively. Two hundred patients admitted between 1998 and 2000 were reviewed retrospectively to form a database of the relevant clinical features. The diagnostic pathway protocol was tested retrospectively in two groups; one hundred with known thoracolumbar fractures and one hundred undifferentiated multi-trauma patients. Sensitivity and specificity indices were determined using the chi-squared test of association.

RESULTS

Falls and motor vehicle crashes were the most common mechanism of injury causing thoracolumbar fractures. No significant association could be found between mechanism of injury (MOI) and presence of thoracolumbar fracture. Clinical signs found to be associated with thoracolumbar fracture include: (1) back pain/midline tenderness (Sens 62.1% Spec 91.5%), (2) palpable midline step (Sens 13.8% Spec 100%), (3) back bruising (Sens 6.9% Spec 98.6%), (4) abnormal neurological signs (Sens 41.4% Spec 95.8%). Cervical level fractures were also found to be associated with an increased incidence of thoracolumbar fractures. Factors found to influence the detection of back pain/midline tenderness include: (1) GCS<15, (2) ETOH/drug intoxication, (3) major distracting injury. The proposed diagnostic pathway would have led to 92% of patients receiving TL imaging in group 2 (multi-trauma) with a sensitivity of 100%, specificity of 11.3% and a negative predictive value of 100%.

CONCLUSION

From the literature and the results of the study, we propose that imaging of the thoracolumbar spine is required in those patients suffering from a high force mechanism of injury if any of the following are present: (1) back pain/midline tenderness, (2) local signs of thoracolumbar injury, (3) abnormal neurological signs, (4) cervical spine fracture, (5) GCS<15, (6) major distracting injury, (7) ETOH/ drug intoxication. An evidence based diagnostic pathway has been shown to be highly sensitive in determining the presence of TL fracture in a retrospective study of blunt trauma patients.

Coiled coil region of streptokinase gamma-domain is essential for plasminogen activation

The specific functions of the amino acid residues in the streptokinase (SK) gamma-domain were analyzed by studying the interactions of human plasminogen (HPlg) and SK mutants prepared by charge-to-alanine mutagenesis. SK with mutations of groups of amino acids outside the coiled coil region of SK gamma-domain, SK(K278A,K279A,E281A,K282A), and SK(D360A,R363A) had similar HPlg activator activities as wild-type SK. However, significant changes of the functions of SK with mutations within the coiled coil region were observed. Both SK(D322A,R324A,D325A) and SK(R330A,D331A,K332A,K334A) had decreased amounts of complex formation with microplasminogen and failed to activate HPlg. SK(D328A,R330A) had a 21-fold reduced catalytic efficiency for HPlg activation. The studies of SK with single amino acid mutation to Ala demonstrate that Arg(324), Asp(325), Lys(332), and Lys(334) play important roles in the formation of a HPlg.SK complex. On the other hand, amino acid residues Asp(322), Asp(328), and Arg(330) of SK are involved in the virgin enzyme induction. Potential contact between Lys(332) of SK and Glu(623) of human microplasmin and strong interactions between Asp(328) and Lys(330), Asp(331) and Lys(334), and Asp(322) and Lys(334) of SK are noticed. These interactions are important in maintaining a coiled coil conformation. Therefore, we conclude that the coiled coil region of SK gamma-domain, SK(Leu(314)-Ala(342)), plays very important roles in HPlg activation by participating in virgin enzyme induction and stabilizing the activator complex.

Gastric choristoma of the hypopharynx presenting in an infant: a case report and review of the literature

Normal gastric mucosa has been found throughout the alimentary tract, ranging from scattered rests of cells to well formed mucosa with submucosal smooth muscle. Many terms have been applied to these collections; however, the term gastric choristoma seems most appropriate. We present a case of hypopharyngeal gastric choristoma presenting with dysphagia and frequent emesis. Our literature review reveals that this is the seventh reported case of gastric choristoma found in the hypopharynx, and the first to present in an infant in the absence of respiratory distress. Excision or CO(2) laser ablation is useful for symptom relief; however, complete removal often requires multiple attempts.

Design of microprism-type symmetric Y-junction waveguides with the full phase compensation method

Using the full phase compensation method, we derive a set of precise phase compensation formulas to design a three-dimensional microprism-type Y junction. The simulated and traditional results are compared to verify that the proposed structure is better. By taking into account the orthogonality principle to estimate the branching losses, the proposed structure was improved to better than approximately 6-10% over the traditional structure.

Systematic design of microprism-type low-loss step-index bent waveguides

By taking into account the curved travel path instead of the conventional abrupt optical line path in the bent region of three-dimensional embedded structures, we propose two kinds of microprism-type waveguide bends and systematically derive precise phase compensation formulas. The simulation results obtained with the fast Fourier-transform beam propagation method indicate that the normalized transmitted powers are greater than 95% even though the bent angle is as large as 10 degrees .

Systematic design of full phase compensation microprism-type low-loss bent waveguides

For traditional microprism-type bent waveguides one must take into consideration only the two outer optical paths to compensate for the phase difference between phase fronts in front of and behind the bent region. We propose a systematic design rule to achieve an optimal phase matching condition by taking account of the whole optical paths for full phase compensation. The simulated results obtained with the fast Fourier transform beam propagation method indicate that the normalized transmitted powers are greater than 95% even though the bent angle is as large as 10 degrees .

Relationship of ceftazidime pharmacokinetic indices with therapeutic outcome in patients with cystic fibrosis

In this study we investigated the relationships between ceftazidime pharmacokinetic indices and clinical outcome measurements during acute pulmonary exacerbations in patients with cystic fibrosis. Twenty patients received ceftazidime during the study period. On Days 2, 7 and 14 outcome measurements were assessed. Ceftazidime peaks and troughs were calculated as was the percentage of time of the dosing interval the serum concentration/minimum inhibitory concentration ratio exceeded 8, 4 and 1. There were significant differences between Days 2 and 7 and between Days 2 and 14 for the outcome measurements. There were no significant between-day differences for the pharmacokinetic indices. Significant correlations, involving both within and between study days, existed between the ceftazidime pharmacokinetic indices and the clinical outcome measurements. Further investigation of these relationships is warranted.

Acute changes in endothelin-1 after hemodialysis for chronic renal failure

Endothelin is a recently described, potent renal vascular and systemic vasoconstrictor peptide. To evaluate the response of this peptide to volume contraction, we measured eight baseline and posthemodialysis samples from seven children, aged 14.5 +/- 3 years, with chronic renal failure. Plasma was extracted and endothelin-1 was measured by radioimmunoassay. Dialysis was performed for a 3- to 3 1/2-hour period, and body weight decreased from 38.0 +/- 14.3 to 36.2 +/- 13.8 kg (p < 0.01) during this time. There were no significant changes in heart rate or respiratory rate after dialysis, but blood pressure fell from 127/80 +/- 22/16 to 114/72 +/- 20/21 mm Hg (p = 0.05 for the systolic pressure). Plasma endothelin-1 concentration increased from 1.5 +/- 1.2 pg/ml at baseline to 7.3 +/- 8.9 pg/ml (p = 0.06) after dialysis; the fall in body weight from dialysis correlated with the increase in endothelin (r = -0.75; p = 0.05). Thus volume contraction from hemodialysis is associated with a rise in plasma endothelin-1, which is related to the acute change in body weight.

Relation of elevated plasma endothelin in congenital heart disease to increased pulmonary blood flow

Endothelin-1 (ET), a potent vasoconstrictor peptide, has been found to be elevated in children with pulmonary hypertension associated with congenital heart defects. To evaluate the effect of pulmonary blood flow on ET concentrations, 5 ml blood samples were obtained peripherally at cardiac catheterization from 35 patients, ages 0.13 to 17 years (median 2). Plasma was extracted and ET measured by radioimmunoassay. Patients were classified into 2 groups based on the presence (group A) or absence (group B) of increased pulmonary blood flow defined as a Qp/Qs > or = 1.5. When the 13 patients (37%) in group A were compared with the 22 patients (63%) in group B there were no significant differences in age, cardiac index, or pulmonary and systemic resistances. ET concentrations were significantly higher in group A patients (median 3.25, range 0 to 16.5 vs median 0, range 0 to 6.35 pg/ml; p < or = 0.05). Pulmonary blood flow and pulmonary artery pressure were also higher in group A patients (p < or = 0.01). When patients within group A were subdivided into those with and without pulmonary hypertension, no difference was present in their ET concentrations (mean/SD: 4.4/4.3 vs 4.0/6.4 pg/ml, p = NS). Thus, ET is elevated in patients with congenital heart disease associated with left-to-right shunts and it appears that this increase is related to increased pulmonary blood flow independent of pulmonary artery pressure.

Effect of ascorbic acid on plasma alcohol clearance

The effects of short-term and long-term ascorbic acid supplements on plasma alcohol clearance were studied in 13 clinically healthy male subjects. Two dose levels of alcohol, 0.5 and 0.8 g/kg body weight, were used. Blood samples were taken at zero time, 0.5 hours, then hourly up to 6 hours after alcohol consumption for the measurement of plasma alcohol and ascorbic acid levels, red-cell reduced glutathione level, and plasma alanine aminotransferase activity. At both dosages of alcohol, short-term as well as long-term pretreatment with ascorbic acid significantly enhanced the clearance of plasma alcohol. Although long-term ascorbic acid pretreatment resulted in better alcohol clearance, no significant difference in alcohol clearance was found between short-term and long-term ascorbic acid pretreatment. The two dose levels of alcohol had no significant effect on the red-cell reduced glutathione concentration or plasma alanine aminotransferase activity.

A frame-shift mutation in the cystic fibrosis gene

Cystic fibrosis (CF) is a common recessive lethal genetic disorder, affecting 1 in 1,600 Caucasians. The disease causes defective regulation of chloride-ion transport in exocrine cells. Although in all CF families the disease is linked to a locus on chromosome 7q31, there is clinical heterogeneity in the severity of the disease and the age at which it is diagnosed. CF is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. A three-nucleotide deletion (delta F508) causing the loss of a phenylalanine residue in the tenth exon of the CFTR gene has been found on 70% of CF chromosomes. We have now characterized a CF family in which neither parent of the affected individual carries the common mutation, and identified a two-nucleotide insertion in the CF allele of the mother. The mutation introduces a termination codon in exon 13 of the CFTR gene at residue 821, and is predicted to result in the production of a severely truncated nonfunctional protein.

The effect of sodium selenite toxicity on tissue distribution of zinc, iron, and copper in rats

Male Sprague-Dawley rats were used to determine the effects of suptoxic and toxic concentrations of selenite in the drinking water on tissue distribution of zinc (Zn), iron (Fe), and copper (Cu). Se (as sodium selenite) was provided in drinking water at concentrations of 0, 2, 4, and 8 ppm. At 19 d, half of the rats in 4 and 8 ppm Sesupplemented groups were kept on drinking water alone for additional 13 d. All rats were sacrificed at the end of 32 d of experiment. Heart, liver, and kidney were analyzed for the concentrations of Fe, Zn, and Cu by atomic absorption spectrophotometry and of Se by a fluorometric method.Results indicated that rats receiving 4 and 8 ppm Se in drinking water showed a marked reduction in food intake and a reduced growth rate. These adverse effects were quickly reversed when high Se intake was discontinued. Se toxicity caused minimal change in zinc status, reduced tissue iron concentrations and caused a marked increase in copper contents in heart, liver, and kidney. The latter findings were only partly reversed after removal of Se in drinking water. The accumulation of Cu in the tissues of Se-toxic rats provides the evidence of some interaction between Se and Cu.

Ethanol-Ascorbate Interrelationship in Acute and Chronic Alcoholism in the Guinea Pig

The effects of low (200 ppm) and of high (2000 ppm) ascorbic acid, in a nutritionally adequate diet, on blood ethanol levels have been studied in permanently carotid-cannulated, ethanol-infused, unanesthetized guinea pigs. In the acute study, the postinfusion rate of ethanol decline in the blood of animals treated with ascorbic acid was significantly higher when compared with animals treated with fructose, and the rate in the two treated groups was significantly higher than in untreated controls. In the chronic study, animals were infused with sublethal doses of ethanol (30% of the total caloric intake) for 8 weeks. Blood ethanol levels monitored throughout this period showed, at 3 hr postinfusion, a lower concentration in the group on a high ascorbic acid diet. Both experimental groups receiving ethanol lost significantly more body weight in the second week of dieting; but, while the group on high ascorbic acid regained weight steadily thereafter, the group on low ascorbic acid was still 50 g below the controls at the end of the experiment. Liver, kidney, and adrenal ascorbic acid concentrations were lower in the ethanol-treated groups compared to controls. Examination of the liver revealed more fatty metamorphosis or steatosis in the low ascorbic acid group, but there was no evidence of liver fibrosis or cirrhosis. These results demonstrate the feasibility of utilizing the guinea pig for the study of the biochemical and morphological sequelae of alcoholism. They further support the contention that a diet which is nutritionally adequate may no longer be so in the presence of high ethanol intake, and that supplemental vitamin C ingestion may afford protection against ethanol toxicity.

The effect of magnesium depletion on thyroid function in rats

The effects of dietary magnesium (Mg) depletion on thyroid function were studied in young male rats. The rats were fed a semipurified diet containing either 12 ppm Mg (deficient rats) or 662 ppm Mg (control rats) for 14 to 28 days. Results showed that the Mg-deficient rats had decreased body weight gain, lowered concentrations of plasma thyroxine (T4) and Mg, but increased weight of the thyroid gland when expressed in proportion to the body weight (milligrams/100 g). There was no difference in the accumulation (uptake) of 131I, 24 hours after Na131I injection, between the Mg-deficient and Mg-supplemented rats. The protein-bound 131I (PB131I) level and the ratio of PB131I to total 131I in plasma was significantly reduced in Mg-deficient rats. Serum thyroid-stimulating hormone (TSH) levels after thyrotropin-releasing hormone injection (TRH, 50 ng/100 g body weight) increased fivefold at 30 minutes, but declined to near the basal level at 2 hours in both groups. No consistent difference in TSH response was observed between the two treatments. Serum T4 response to TRH challenge was significantly reduced in Mg-deficient as compared to Mg-adequate rats at all time intervals. The reduction of T4 level could be due to an impaired T4 synthesis or release in Mg-deficient rats.

Cysteine feeding affects urinary zinc excretion in normal and ethanol-treated rats

The effects of L-cysteine feeding on urinary zinc excretion were studied in normal and ethanol-treated rats. In rats fed 3% cysteine X HCl for 1-10 weeks, a three-fold increase of urinary zinc excretion was observed. That effect was variable but was significant throughout the experimental weeks. Despite the excessive zinc loss, cysteine-fed animals showed no evidence of zinc depletion as judged by zinc concentrations in plasma, hair, spleen, pancreas and muscle. Furthermore, zinc contents in liver, kidney and tibia were significantly higher in cysteine-fed rats than in their controls. In rats consuming 20% ethanol for 5 months, urinary excretion of magnesium was markedly elevated and of zinc, only slightly elevated. When rats that drank either 20% ethanol or an isocaloric sucrose solution were fed the cysteine-fortified diet, elevations of urinary zinc excretion were similar. Cysteine intake apparently did not affect urinary excretion of copper and magnesium. Diets supplemented with DL-ethionine or L-cystine, but not inorganic sulfate, methionine or ascorbic acid, induced minor elevation of urinary zinc output. Those findings suggest that cysteine has a specific role in zinc metabolism.

Impairment of ascorbic acid synthesis in liver extracts of magnesium-deficient rats

The effect of feeding a magnesium (Mg)-deficient diet for 9-34 days to weanling and young male rats on urinary and tissue ascorbate levels were studied. The concentrations of ascorbic acid in the liver and kidney were significantly reduced in the rats receiving a Mg-deficient diet as compared to those receiving a Mg-supplemented diet. The response to trichloro-2-methyl-2-propanol stimulation of urinary ascorbic acid was found to be considerably suppressed by dietary deficiency of Mg, suggesting that the decrease was not due to feed intake. In in vitro studies, the enzymatic synthesis of the vitamin from glucuronolactone or gulonolactone by liver extracts from Mg-deficient rats was significantly decreased as compared with Mg-supplemented rats. These results suggest that Mg-deficient rats have a reduced capacity to synthesize ascorbate which in turn produces a decrease in ascorbic acid concentrations in the liver.

Role of magnesium in glutathione metabolism of rat erythrocytes

The effects of dietary magnesium (Mg) on glutathione (GSH) metabolism were studied in rat erythrocytes. Young male and young adult female rats were fed a powdered diet containing either 12 ppm Mg (deficient rats) or 662 ppm Mg (control rats) for 14 to 28 days. Results showed that Mg deficiency in male rats had a decreased body weight gain, lower values in plasma hematocrit and Mg ion, but increased organ weights. The concentrations of erythrocyte GSH as measured by alloxan were reduced in male and female rats receiving a Mg-deficient diet. This decrease was confirmed by determining GSH with DTNB reagent [5,5'-dithiobis(2-nitrobenzoic acid)]. Mg-deficient rats, however, had higher levels of liver and kidney GSH, but no effect in other soft tissues examined. The decrease of erythrocyte GSH was not due to feed intake, the availability of its precursors, or the activities of GSH-related enzymes and can be reversed by Mg supplementation. Mg-deficient rats had a reduced blood ATP and a 6-fold increase in the activity of plasma gamma-glutamyl transpeptidase. These findings suggest that Mg is essential in the maintenance of GSH concentration to protect against oxidative damage in the erythrocyte membrane.

Effect of zinc deficiency on histidine metabolism in rats

The effects of feeding a diet deficient in zinc (Zn) to male rats on histidine metabolism were studied. Results showed that significantly higher percentages of DL-histidine-carboxyl-14C and L-histidine-2-(ring)-14C were oxidized by Zn-deficient rats. The incorporation of L-histidine-2-(ring)-14C into the proteins of skin, muscle, and kidney were significantly reduced in Zn-deficient rats as compared to Zn-supplemented rats. Conversely, the radioactivity of liver protein of Zn-deficient rats was significantly increased. Zn deficiency increased the activities of liver histidase and urocanase but had no effect on the activity of liver histidine-pyruvate transaminase. The increases of enzymatic activities were not due to food intake and can be prevented upon Zn repletion. The liver of Zn-deficient rats contained normal amount of histidine but a reduced quantity of histamine. The results on urinary excretion indicated that Zn-deficient rats discharged the same amounts of one-methyl and three-methyl histidine as Zn-supplemented pair-fed rats. Overall findings support in principle the concept that Zn deficiency results in disturbances of protein metabolism and also indicate that Zn is an important factor in regulating histidine metabolism through the urocanic acid pathway.

Lead toxicity as related to glutathione metabolism

The effect of lead poisoning on glutathione metabolism was studied in rat pups born of dams receiving a commercial laboratory diet supplemented with 0.5% lead acetate. Results showed that the body weight gain of the first 3 weeks of life and at the age of 6 weeks was significantly less in both male and female pups nourished by lead-fed dams than those raised by dams receiving the lab diet. Lead ingestion decreased hematocrit levels and hemoglobin values and increased the weights of liver, kidney, spleen and brain. Concentrations of plasma free histidine, glutamic acid and serine were decreased in lead-poisoned rats but glycine levels were markedly increased. After 4 weeks of lead feeding, both sexes had an increased glutathione concentration in erythrocytes, liver and kidney. Isotope studies further indicated that the incorporation of cystine-35S was significantly increased in glutathione but decreased in protein of liver and kidney of lead-fed rats. Similarly, lead ingestion significantly increased glycine-1-14C incorporation into renal glutathione. However, the activities of glutathione reductase and glutathione peroxidase were unaffected by lead poisoning. The data suggest a compensatory mechanism operates to overcome the toxicity of ingested lead by maintaining a high concentration of glutathione in the liver and kidney.

Effects of ethionine feeding on urinary and tissue ascorbic acid concentrations in rats

The effect of feeding 0.25% ethionine for 3-10 weeks to male and female rats on urinary and tissue ascorbate contents were studied. The concentrations of ascorbic acid in the urine, blood, liver and adrenals were significantly reduced in the rats receiving ethionine as compared to those receiving stock diet. This decrease was not apparently due to feed intake, not reversed by supplementation of methionine, but can be partially restored by removing ethionine from stock diet. The response to trichloro-2-methyl-2-propanol stimulation of urinary ascorbic acid was considerably suppressed by ethionine administration. In vitro the enzymatic synthesis of the vitamin from glucuronolactone by liver homogenate of ethionine-fed rats was significantly decreased from that of stock diet-fed controls. These results indicate that ethionine reduces the capacity to synthesize ascorbate which, in turn, causes a decrease of ascorbic acid contents in the urine, blood, liver and adrenals.

Hypomyelination in copper-deficient rats. Prenatal and postnatal copper replacement

Copper deficiency induced by a low copper diet in three generations of rats was associated with substantial reductions in the yield of myelin (56%), brain weight (11%), and body weight (43%) in F2 generation rat pups nursed by their own copper-deficient mothers. The composition of the purified myelin was not different from that of controls in the content of individual proteins, lipids, 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) activity, or GM1 ganglioside. The major myelin-associated glycoprotein (mGP) was consistently shifted slightly toward higher apparent molecular weight in the copper-deficient animals. Postnatal copper replacement by a foster mother produced a normal yield of myelin per gram of brain tissue, but failed to reverse the deficiency of brain and body growth. After copper replacement in a copper-deficient mother's diet prior to conception, a subsequent litter showed correction of all abnormalities found in her previous litters. The results suggest that copper is essential for myelin formation and general growth during critical periods in development.

Enzyme activities in the epidermis of zinc-deficient rats

Fifteen enzymes participating in epidermal energy metabolism in zinc-deficient and -supplemented rats were assayed utilizing fluorometric microchemical techniques. In the zinc-deficient group, the activities of six enzymes catalyzing glycolysis decreased by 30 to 50% of the control; the most dramatic decreases were found in phosphofructokinase and glyceraldehyde-3-phosphate dehydrogenase. Zinc deficiency caused a 31% decrease in the activity of glucose-6-phosphate dehydrogenase, a 63% decrease in fumarate hydratase, a 46% decrease in glutamate dehydrogenase, and a 30 to 40% decrease in aminotransferases.

Free amino acids in plasma and tissue of rats born to underfed dams

Amino acids were determined in plasma, muscle, and liver tissues of adult male rats born of mothers on restricted or nonrestricted diets during pregnancy and lactation. The concentrations of plasma alanine, glutamic acid, glycine, proline, arginine, and valine were significantly lower in the progeny of restricted mothers as compared to non-restricted mothers. Similar changes were observed in liver tissues. The concentrations of free amino acids in muscle of the perinatally malnourished progeny, however, did not differ significantly from those of the controls. The differences determined in this study are of special significance in view of the fact that the animals studied had been maintained on an adequate diet since weaning. The demonstrated effect of the maternal diet on the plasma aminogram of the off-spring some months later must be considered when interpreting plasma aminograms in studies of malnourished children.

Effect of zinc deficiency and repletion on thymidine metabolism

We studied the effect of zinc deficiency on thymidine metabolism in intact and wounded rats. Zinc deficiency was associated with significantly decreased incorporation of [methyl-3H] thymidine into skin DNA of both intact and wounded rats, as shown by liquid scintillation counting and autoradiography. With wounding, proliferation--as gauged by the labeling index--increased to about twice normal for zinc-supplemented rats, but 3.5-fold for zinc-deficient rats. However, despite the increased proliferation rate, wound-healing in deficient rats was always slower than in zinc-supplemented animals. Incorporation of 3H-labeled thymidine into spleen DNA at 2 and 4 h, and liver DNA at 4 h was also significantly less in zinc-deficient rats than in zinc-supplemented rats. Conversely, DNA synthesis was enhanced in the thymus gland of zinc-deficient rats. Further studies showed that significantly higher percentages of [methyl-14C] thymidine were oxidized by zinc-deficient rats. The specific involvement of the methyl group of thymidine was indicated by the observation of normal oxidattions of [2-14C] thymidine. These findings support the view that zinc directly regulates DNA synthesis.

Pure culture studies of Erwinia carotovora with 3,5-diiodo-4-hydroxybenzonitrile

Interactions of ioxynil (3,5-diiodo-4-hydroxybenzonitrile) with a pure culture of Erwinia carotovora grown in a glucose-simple salts medium were studied. Growth of E. carotovora was inhibited by ioxynil and, to a lesser extent, by its acid form at 25 and 50 mug/ml. Growth was not inhibited by the amide or ester forms of ioxynil or p-hydroxybenzonitrile at the same concentrations. E. carotovora could be trained to grow in 50 mug or higher concentrations of ioxynil per ml by serial transfers of the organism through increasing ioxynil concentrations. No degradation or detoxification of ioxynil was detected. Toxicity tests indicated that, in the adapted culture, cell-free supernatant fluid remained toxic to a nonadapted culture. Adaptation of E. carotovora resulted in a lengthened lag phase, a decreased growth rate, and very few adverse effects on the total population. The adapted resistant culture retained this characteristic only when ioxynil was present. Adaptation was demonstrated to be a physiological variation, not a selection of a mutant or of preexisting resistant cells. Ioxynil slightly stimulated the respiration rate of E. carotovora and moderately inhibited that of an adapted culture. Because the respiration rate of an adapted culture in the absence of ioxynil surpassed that of a parent culture still in the presence of ioxynil, a competition of two alternate routes of electron transport is implied. These data support the conclusion that an alternate growth mechanism is involved in the adaptation mechanism.