Potassium carbonate as a supplement to improve milk fat concentration and yield in early-lactating dairy goats fed a high-starch, low-fiber diet.

This study investigated the use of K2CO3 as dietary buffer to prevent or to recover from low milk fat production when early-lactating dairy goats are fed a high-starch, low-fiber (HSLF) diet. At kidding, 30 Alpine goats housed in pens with Calan gate feeders received a total mixed ration with a forage-to-concentrate ratio of 55:45 on a dry matter (DM) basis for a baseline period of 27 ± 4 d. Goats (milk yield, 4.14 ± 0.88 kg/d; milk fat, 4.28 ± 0.52%; mean ± SD) were then assigned to 1 of 10 blocks according to parity (first vs. second or more) and milk fat concentration, and fed a HSLF diet containing 45% forages and 55% concentrates for 2 experimental periods of 28 d. Treatments were identified as (1) control, in which the HSLF diet was fed throughout both periods; (2) preventive, in which the HSLF diet supplemented with K2CO3 (1.6% of DM) was fed during both periods; and (3) recovery, in which the HSLF diet was fed during the first period (P1) and the HSLF diet supplemented with K2CO3 was fed during the second period (P2). Data from P1 and P2 were analyzed separately. In P1, preplanned contrasts were used to evaluate the preventive effect of K2CO3 (control and recovery, both groups receiving the same diet during this period, vs. preventive), and in P2, to assess the potential of K2CO3 to alleviate an already existing state of low milk fat (control vs. recovery and preventive vs. recovery). Feeding the HSLF diet in P1 moderately decreased milk fat concentration (-16%) and yield (-13%) as compared with baseline. Dietary addition of K2CO3 decreased DM intake by 12 and 14% in P1 and P2, respectively. Ruminal pH was not different among treatments. There was also no significant difference in milk yield (4.13 and 3.71 kg/d on average in P1 and P2, respectively) for any tested contrasts. In P1, milk fat concentration and yield did not differ among goats fed control (3.58% and 151 g/d, respectively) and preventive (3.67% and 148 g/d, respectively) diets. In P2, milk fat concentration and yield did not differ among goats fed the control diet (3.38% and 137 g/d, respectively), and diets where K2CO3 was used as preventive (3.44% and 126 g/d, respectively) or recovery treatment (3.25% and 113 g/d, respectively). Supplementing a high-concentrate diet with 1.6% K2CO3 was therefore not effective in either preventing or suppressing already existing conditions of low milk fat production in dairy goats.

Cardiac hemodynamics in fetuses with transposition of the great arteries and intact ventricular septum from diagnosis to end of pregnancy: longitudinal follow-up.

OBJECTIVES: Little is known about cardiac hemodynamics in the fetus with transposition of the great arteries and intact ventricular septum (TGA-IVS). Better understanding of the fetal physiology in TGA-IVS would help to provide insights into specific clinical complications observed after birth, in particular neonatal hypoxia and pulmonary hypertension. The aim of this study was to assess cardiac hemodynamics in fetuses with TGA-IVS by performing systematic longitudinal echocardiographic follow-up from diagnosis to delivery. METHODS: This was a longitudinal retrospective study of fetuses referred between 2010 and 2018 to the Sainte-Justine University Hospital Centre. Complete assessment of cardiac hemodynamics was performed in fetuses with TGA-IVS at 18-22, 28-32 and 35-38 weeks' gestation, which were compared with normal fetuses matched for gestational age. The maximum diameter of the foramen ovale was measured using two-dimensional echocardiography under the guidance of color Doppler echocardiography. Fetal cardiac hemodynamics were analyzed according to postnatal preductal transcutaneous oxygen saturation (TcSO2 ) < 65% or ≥ 65%, as a neonatal outcome, in fetuses with TGA-IVS. RESULTS: In total, 59 fetuses with TGA-IVS and 160 normal fetuses were included. Global cardiac output was significantly higher in fetuses with TGA-IVS than in controls, mainly owing to higher global pulmonary output, while global systemic cardiac output did not differ between TGA-IVS fetuses and controls throughout pregnancy. Aortic flow (right ventricular output in fetuses with TGA-IVS, left ventricular output in controls) was significantly higher in fetuses with TGA-IVS than in normal fetuses. Ductal flow was significantly lower in fetuses with TGA-IVS at every timepoint, and this difference increased considerably after 28-32 weeks. In parallel, the diameter of the foramen ovale was significantly smaller in fetuses with TGA-IVS at 28-32 and 35-38 weeks, with a stagnation in growth after 28 weeks, compared with continuous growth in normal fetuses. Most of these cardiac hemodynamic anomalies in fetuses with TGA-IVS were already present at 18-22 weeks, and the differences became greater at 28-32 weeks' gestation. TGA-IVS neonates with TcSO2 < 65% had lower fetal left ventricular output, higher diastolic ductal retrograde flow and smaller foramen ovale at 28-32 weeks, compared with fetal values in those with postnatal TcSO2 ≥ 65%. CONCLUSIONS: Compared with normal fetuses, those with TGA-IVS undergo a complex redistribution of blood flow during the second half of pregnancy, with higher global pulmonary flow, lower ductal flow (with negative diastolic flow at the end of pregnancy) and a smaller foramen ovale. In addition, fetal cardiac hemodynamic anomalies observed at 28-32 weeks' gestation were associated with lower postnatal TcSO2 . These observations may provide a better understanding of premature closure of the foramen ovale and postnatal hypoxia that are specific to TGA-IVS physiology. © 2019 International Society of Ultrasound in Obstetrics and Gynecology.

Prenatal diagnosis and prognosis of accelerated idioventricular rhythm.

OBJECTIVES: As postnatal identification of accelerated idioventricular rhythm (AIVR) relies on specific electrocardiographic patterns, prenatal diagnosis of this condition is challenging and its true incidence is unknown. The objectives of this study were to evaluate the performance of prenatal ultrasonography in identifying intrauterine cardiocirculatory events linked to specific electrocardiographic signs of postnatal AIVR, including left or right ventricular origin, and to assess the prenatal prognosis of this arrhythmia. METHODS: We reviewed Doppler tracings from the superior vena cava/ascending aorta (SVC/Ao), ductus venosus (DV), ductus arteriosus (DA) and aortic isthmus (AoI), as well as simultaneous M-mode recordings of septal and left ventricular wall motions of fetuses diagnosed with AIVR from January 2004 to December 2014. RESULTS: Three cases of AIVR were identified among 27 912 fetuses. SVC/Ao Doppler flow recordings revealed atrioventricular dissociation (ventricular rates within 20% of atrial rates) in all three fetuses and episodes of isorhythmic atrioventricular dissociation in one, while M-mode confirmed normal left ventricular shortening fraction in all cases. Fusion beats were observed on AoI tracing in one fetus, while simultaneous recordings of AoI and DA revealed signs of right bundle branch block in one case and left bundle branch block in the other two. On DV Doppler recordings, retrograde a-waves in the presence of simultaneous atrial and ventricular contractions were observed in all three fetuses, leading to an increase in central venous pressure in all and hydrops fetalis in two cases without evidence of ventricular dysfunction. CONCLUSIONS: Echocardiographic criteria required for postnatal diagnosis of AIVR can be documented in utero using specific ultrasonographic approaches. During fetal life, AIVR may not be a benign entity. Hydrops fetalis is frequently associated with AIVR because of increase in central venous pressure related to simultaneous atrioventricular contractions; thus, the ultrasonographic investigation protocol of fetuses with unexplained hydrops fetalis should aim at ruling out AIVR and include Doppler flow recordings in SVC/Ao, DV, AoI, DA and umbilical vein. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Effects of grain source, grain processing, and protein degradability on rumen kinetics and microbial protein synthesis in Boer kids.

Microbial protein synthesis in the rumen would be optimized when dietary carbohydrates and proteins have synchronized rates and extent of degradation. The aim of this study was to evaluate the effect of varying ruminal degradation rate of energy and nitrogen sources on intake, nitrogen balance, microbial protein yield, and kinetics of nutrients in the rumen of growing kids. Eight Boer goats (38.2 ± 3.0 kg) were used. The treatments were arranged in a split-plot Latin square design with grain sources (barley or corn) forming the main plots (squares). Grain processing methods and levels of protein degradability formed the subplots in a 2 × 2 factorial arrangement for a total of 8 dietary treatments. The grain processing method was rolling for barley and cracking for corn. Levels of protein degradability were obtained by feeding untreated soybean meal (SBM) or heat-treated soybean meal (HSBM). Each experimental period lasted 21 d, consisting of a 10-d adaptation period, a 7-d digestibility determination period, and a 4-d rumen evacuation and sampling period. Kids fed with corn had higher purine derivatives (PD) excretion when coupled with SBM compared with HSBM and the opposite occurred with barley-fed kids ( ≤ 0.01). Unprocessed grain offered with SBM led to higher PD excretion than with HSBM whereas protein degradability had no effect when processed grain was fed ( ≤ 0.03). Results of the current experiment with high-concentrate diets showed that microbial N synthesis could be maximized in goat kids by combining slowly fermented grains (corn or unprocessed grains) with a highly degradable protein supplement (SBM). With barley, a more rapidly fermented grain, a greater microbial N synthesis was observed when supplementing a low-degradable protein (HSBM).

Long-term follow-up of patients with papillary and follicular thyroid cancer: a prospective study on 715 patients.

PURPOSE: This prospective study evaluated the recurrence rate in 715 patients with differentiated thyroid cancer who had no evidence of persistent disease after total thyroidectomy and lymph node dissection in 94% of them followed up by radioiodine ablation (30-100 mCi) and assessed the predictive value of the initial thyroglobulin (Tg) levels for detecting recurrence, both during levothyroxine (LT4) treatment and after TSH stimulation. PATIENTS AND METHODS: Patients had Tg determinations performed at 3 months on LT4 treatment (Tg1) and at 9-12 months after stimulation by either thyroid hormone withdrawal or recombinant human TSH (Tg2); the Access kit was used (functional sensitivity of 0.11 ng/ml); they had undetectable anti-Tg antibodies. Patients were followed up annually. Predictive values were calculated by comparing Tg levels (Tg1 and Tg2) and the outcome in terms of recurrence. RESULTS: During the median follow-up of 6.2 yr, 32 patients had a recurrence. Assuming a cutoff level for Tg1 at 0.27 ng/ml, Tg1 sensitivity and specificity reached 72 and 86%, respectively, whereas predictive positive and negative values were 20 and 99%, respectively. With a cutoff level for Tg2 at 1.4 ng/ml, sensitivity and specificity reached 78 and 90%, respectively, whereas positive and negative predictive values were 26 and 99%, respectively. CONCLUSION: This large prospective cohort of patients presented a low rate of recurrence. Initial Tg measurements allow to predict long-term recurrence with an excellent specificity. Stimulated Tg determination presented a slightly higher sensitivity than Tg determination on LT4. TSH stimulation may be avoided when Tg measured 3 months after ablation is less than 0.27 ng/ml during LT4 treatment.

Molecular targeted therapies for patients with refractory thyroid cancer.

The recent availability of molecular targeted therapies leads to reconsideration of the treatment strategy in patients with distant metastases from differentiated thyroid carcinoma who are resistant to radioiodine therapy, and in patients with metastatic medullary thyroid carcinoma. In patients with progressive disease, treatment with kinase inhibitors should be offered, preferably in the context of a prospective trial.

Feasibility and reliability of Doppler flow recordings in the fetal aortic isthmus: a multicenter evaluation.

OBJECTIVES: To evaluate the performance of three different centers with respect to their ability to identify the fetal aortic isthmus (AoI) adequately and place a Doppler sample volume in the AoI correctly, and to address the reproducibility of the isthmic flow index (IFI) calculated from Doppler waveforms recorded in the three centers. METHODS: The three collaborating centers sent several ultrasonographic recordings taken at random over a 6-week period to the Saint-Justine Fetal Cardiology Unit (StJ-FCU). A performance quotient ((number of total readings - number of unsatisfactory results)/number of total readings) was calculated for each center by each of three judges, who were experienced fetal cardiologists, to assess the ability of each center to identify the isthmus and to place the Doppler sample volume (DSV) adequately. Intraclass correlation coefficients (ICC) were computed to quantify the variability of IFI measurements ((systolic + diastolic)/systolic flow velocity integrals). RESULTS: Fifty-five recordings were available for this study. Concerning isthmus identification, there was 100% agreement between the three judges from StJ-FCU and the performance quotients of Centers A, B and C were: 0.90, 0.95 and 1.00, respectively. For DSV positioning, agreement between the judges varied; for Judge 1 vs. Judge 2, kappa = 0.836 (95% CI, 0.651-1.000); for Judge 1 vs. Judge 3, kappa = 0.773 (95% CI, 0.557-1.000); for Judge 2 vs. Judge 3, kappa = 0.941 (95% CI, 0.805-1.000). The performance quotients of the three centers for DSV positioning were consistently lower than were those for identification of the isthmus, being 0.85, 0.76 and 0.92, respectively. The ICC between the first and second measurements of the IFI by Rater 1 was 0.96 (95% CI, 0.93-0.98, P < 0.001) and that between Raters 1 and 2 was 0.97 (95% CI, 0.95-0.99, P < 0.001). CONCLUSION: Adequate imaging of the fetal AoI can be achieved easily by a trained sonographer, while DSV positioning is challenging. The intra- and interrater variability of the IFI are low.

Management of fetal tachyarrhythmia based on superior vena cava/aorta Doppler flow recordings.

OBJECTIVE: To evaluate a management protocol of fetal supraventricular tachycardia (SVT) based on prior identification of the underlying mechanism. DESIGN AND SETTING: Prospective study in a mother-child tertiary university centre. PATIENTS: During a consecutive 36 month period, 18 fetuses with sustained SVT underwent a superior vena cava/ascending aorta (SVC/AA) Doppler investigation in an attempt to determine the atrioventricular (AV) relation and to treat the arrhythmia according to a pre-established management protocol. MAIN OUTCOME MEASURE: Rate of conversion to sinus rhythm. RESULTS: Seven fetuses had short ventriculoatrial tachycardia, five of these with a 1:1 AV conduction suggesting re-entrant tachycardia. The first choice drug was digoxin and all were converted. One fetus had AV dissociation leading to the diagnosis of junctional ectopic tachycardia, which was resistant to digoxin and sotalol; amiodarone achieved postnatal conversion. One fetus had SVT and first or second AV block; the diagnosis was atrial ectopic tachycardia (AET), which responded to sotalol given as a drug of first choice. Seven fetuses had long ventriculoatrial tachycardia: one with sinus tachycardia (no treatment), one with permanent junctional reciprocating tachycardia (PJRT), and three with AET. The first choice drug was sotalol and all were converted. One AET was classified postnatally as PJRT. Six fetuses had intra-atrial re-entrant tachycardia: five with 2:1 AV conduction and one with variable block. The first choice drug was digoxin. Conversion was achieved in all but one, who died after birth from advanced cardiomyopathy. CONCLUSION: The electrophysiological mechanisms of fetal SVT can be clarified with SVC/AA Doppler. The proposed management protocol has so far yielded a good rate of conversion to sinus rhythm.

Comparable efficacy and safety profiles of once-per-cycle pegfilgrastim and daily injection filgrastim in chemotherapy-induced neutropenia: a multicenter dose-finding study in women with breast cancer.

BACKGROUND: Neutropenia is common in patients receiving myelotoxic chemotherapy. Pegfilgrastim, a sustained-duration filgrastim is a once-per-cycle therapy for prophylactic neutrophil support. PATIENTS AND METHODS: Women, treated with four cycles of doxorubicin/docetaxel chemotherapy every 21 days, received pegfilgrastim or filgrastim 24 h after chemotherapy as a single subcutaneous injection per chemotherapy cycle (pegfilgrastim 30, 60 or 100 microg/kg) or daily subcutaneous injections (filgrastim 5 microg/kg/day). Safety, efficacy and pharmacokinetics were analyzed. RESULTS: The incidence of grade 4 neutropenia in cycle 1 was 95, 90 and 74%, in patients who received pegfilgrastim 30, 60 and 100 microg/kg, respectively, and 76% in patients who received filgrastim. Mean duration of grade 4 neutropenia in cycle 1 was 2.7,2 and 1.3 days for doses of pegfilgrastim, and 1.6 days for filgrastim. The pharmacokinetics of pegfilgrastim were non-linear and dependent on both dose and neutrophil count. Pegfilgrastim serum concentration was sustained until the neutrophil nadir occurred then declined rapidly as neutrophils started to recover, consistent with a self-regulating neutrophil-mediated clearance mechanism. The safety profiles of pegfilgrastim and filgrastim were similar. CONCLUSIONS: A single subcutaneous injection of pegfilgrastim 100 microg/kg provided neutrophil support and a safety profile comparable to daily subcutaneous injections of filgrastim during multiple chemotherapy cycles.

Does modularity affect clinical success? A comparison with a minimum 10-year followup.

A comparison of the clinical and radiographic results of patients with metal-backed monoblock Insall-Burstein I and modular Insall-Burstein II Posterior Stabilized Knee Prostheses was done. The minimum followup was 10 years. The clinical results were comparable with a similar average Hospital for Special Surgery knee score of 85 and 84 points, respectively. Likewise, the Knee Society Knee and Functional Scores showed no statistical difference. Radiographically, the incidence of minor radiolucent lines was 11% for the Insall-Burstein I prostheses and 29% for the Insall-Burstein II prostheses, but their presence was of no clinical significance. There was no clinical or radiographic evidence of tibial component loosening with either prosthetic design and there were no revisions for polyethylene wear or osteolysis in either cohort of patients.

Prognostic markers in twin pregnancies with an acardiac fetus.

OBJECTIVE: With twin reversed arterial perfusion sequence, the normal cotwin is at risk of heart failure. The purpose of this study was to identify ultrasonographic variables that can help predict prognosis. We hypothesized that variables reflecting the hyperdynamic circulatory condition of the normal fetus and the changes in circulatory impedance in the acardiac mass would correlate with final outcome. METHODS: Ten twin pregnancies with this condition were identified. Follow-up was available for nine. Adverse outcome was defined as death, cardiac failure, or delivery before 30 weeks' gestation for reasons related to the presence of the mass. The following data were collected on the normal fetus: cardiothoracic ratio and left ventricular shortening fraction; and on the mass: maximal length, presence and size of cysts, and presence of a rudimentary heart. The pulsatility index (PI) of the umbilical arteries (UA) of both twins was measured. RESULTS: Four fetuses died, two in utero (22 weeks) and two after cesarean (26 and 31 weeks) for advanced cardiac failure. In the five other cases, the outcome was favorable. The cardiothoracic ratio and presence of cysts or of a rudimentary heart did not correlate with outcome. A PI in the mass' UA significantly lower than that of the normal twin (ratio of 0.71 compared with 1.04 for good outcome, P<.05), an elevated shortening fraction in the second trimester, and a rapid growth rate of the mass were associated with a poor prognosis. CONCLUSION: In pregnancies with twin reversed arterial perfusion sequence, final outcome and treatment decisions can be determined based on hemodynamic criteria.

A phase I/II trial of neoadjuvant chemotherapy with cisplatin and vinorelbine followed by accelerated irradiation for patients with inoperable nonsmall cell lung carcinoma.

BACKGROUND: Both locoregional and distant disease control remains poor in the treatment of Stage III nonsmall cell lung carcinoma (NSCLC). This trial was conducted to evaluate the tolerance and responses of patients with NSCLC given a neoadjuvant regimen of cisplatin and vinorelbine chemotherapy followed by accelerated thoracic radiotherapy. METHODS: Forty-two patients with Stage IIIA and IIIB NSCLC were entered into the study. Treatment consisted of cisplatin 100 mg/m2 given on Days 1 and 29 and vinorelbine 30 mg/m2 given weekly for 5 weeks, with a planned 50% dose reduction to 15 mg/m2 planned for Week 2. This was followed by thoracic irradiation of 60 gray (Gy) in 30 fractions of 2 Gy over 4 weeks (once daily during Weeks 1 and 2 and twice daily during Weeks 3 and 4). RESULTS: With a median follow-up time of 12.2 months (27-65 months for survivors), the median survival was 12.2 months (16.6 months for patients with no prior weight loss and 7.8 months for those with prior weight loss). The response rate after induction chemotherapy was 46.1%, increasing to 74.4% after radiation therapy (8 complete responses and 21 partial responses). The rate of progression was 13 of 18 (72%) for those who responded to chemotherapy (4 distant, 9 local) and 18 of 21 (86%) for those who did not respond to chemotherapy (14 distant, 7 local). The most frequent acute Grade 3 toxicity was nausea (21.4%). CONCLUSIONS: Accelerated thoracic irradiation after induction chemotherapy is well tolerated and yields therapeutic results that compare favorably with those reported for other regimens of chemotherapy and standard fractionated radiotherapy. The data from this study suggest that the responses of patients with clinically apparent disease to induction chemotherapy might indicate a likelihood of controlling microscopic distant metastases.

Outcome of children with atrial septal defect considered too small for surgical closure.

There are few studies providing information on the natural course of hemodynamically insignificant atrial septal defect (ASD). To review the outcome of patients with secundum ASD, we retrospectively reviewed the charts of patients who had initially not been considered for surgical closure after age 1 year, and who had either a follow-up of at least 10 years or documented closure. Thirty patients, 22 females and 8 males, fulfilled our inclusion criteria. Mean age at diagnosis was 1.3 year and mean follow-up duration was 11.5 years. Seventeen patients had spontaneous closure of the ASD at a mean age of 8.4 years. There were 7 asymptomatic patients whose ASD was still patent at the last visit (mean age 14.1 years, mean follow-up 13.2), with defect dimensions on echocardiography ranging from 1 to 6 mm. The remaining 6 patients were considered to require surgical closure on the basis of an apparent increase in size of the ASD and secondary clinical and hemodynamic manifestations. These results (1) confirm that not all secundum ASDs need to be treated surgically because they can still spontaneously close past the age of 5, and (2) suggest that in a minority of cases the size of the defect could increase.

Treatment of unicameral bone cyst with demineralized bone matrix.

Eleven patients with active unicameral bone cysts were treated primarily with placement of demineralized bone matrix in the cyst by using a two-needle technique and a custom large-bore needle. Cyst healing was rated according to the Neer classification, and the average time of healing was 4.5 months. The demineralized bone matrix demonstrated an ability to obliterate the cyst in nine of 11 patients by using a single injection within 4-5 months, and at 2 years' follow-up, no cysts were deemed active or recurrent.

The Psychological Maltreatment Rating Scales.

Psychological maltreatment is gaining recognition as one of the core concepts in child welfare, however, its utility has been limited by definitional problems and the absence of operationalized and validated instruments. These Psychological Maltreatment Rating Scales (PMRS) were developed for assessing psychological maltreatment in mother-child interaction, and were used to rate the videotaped interaction of 49 high-risk mother-child dyads and make predictions of child protective service involvement with the dyads. These predictions are compared with predictions based upon mothers' personal resources and social support. Results show that the PMRS is a moderately reliable and valid measure of psychologically maltreating and prosocial parental behavior that can discriminate between maltreating and comparison parents, and is a more effective predictor than maternal measures. Three factors of parenting emerged from an exploratory factor analysis: emotional abuse, and two factors of positive parenting. Psychological abuse was the presence of hostile behavior, and psychological neglect the absence of positive parenting.

Direct evidence that an increase in aortic norepinephrine level in response to insulin-induced hypoglycemia is due to increased adrenal norepinephrine output.

This study reports on the major source of circulating norepinephrine that is known to increase, progressively, during sustained hypoglycemia induced by intravenous insulin administration. Plasma concentrations of epinephrine, norepinephrine, and dopamine were simultaneously determined for adrenal venous and aortic blood in dogs anesthetized with sodium pentobarbital. The model used allowed us to perform a functional adrenalectomy (ADRX), while continuously monitoring the adrenal medullary secretory function. Under basal conditions, the net output (micrograms/min) of adrenal epinephrine, norepinephrine, and dopamine were 0.169 +/- 0.074, 0.067 +/- 0.023, and 0.011 +/- 0.003, respectively. Plasma concentrations (ng/mL) of aortic epinephrine, norepinephrine, and dopamine were 0.132 +/- 0.047, 0.268 +/- 0.034, and 0.034 +/- 0.009. Following insulin injection (0.15 IU/kg, i.v.), the net output (micrograms/min) of adrenal epinephrine, norepinephrine, and dopamine increased gradually (p less than 0.05), reaching the values of 0.918 +/- 0.200, 0.365 +/- 0.058, and 0.034 +/- 0.007 30 min after insulin administration. Similarly, aortic epinephrine, norepinephrine, and dopamine concentrations (ng/mL) increased significantly (p less than 0.05) to 0.702 +/- 0.144, 0.526 +/- 0.093, and 0.066 +/- 0.024. The aortic glucose concentration (mg/dL) was diminished from 81.8 +/- 4.1 to 36.9 +/- 3.4 (p less than 0.01). After taking the blood sample at 30 min following insulin administration, ADRX was immediately performed. Five minutes after the onset of ADRX, the net output (micrograms/min) of adrenal epinephrine, norepinephrine, and dopamine increased further to 1.707 +/- 0.374 (p less than 0.05), 0.668 +/- 0.139 (p less than 0.05), and 0.052 +/- 0.017.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence that increases in circulating catecholamines of adrenal origin are not involved in pressor response to bilateral carotid occlusion in anaesthetized dogs.

1. We studied whether or not circulating catecholamines of adrenal origin play a major role in cardiovascular responses evoked by bilateral carotid artery occlusion (3 min) in anaesthetized dogs. 2. In the control group, the following parameters increased significantly (P less than 0.05) during bilateral carotid occlusion: aortic systolic pressure, heart rate, net adrenal catecholamine output, net renal noradrenaline output, and plasma catecholamine concentrations in aortic blood. Similar responses were obtained during the second occlusion performed approximately 25 min after the first occlusion. 3. After functional adrenalectomy (ADRX: diversion of adrenal venous blood flow), the increase in aortic adrenaline concentration observed during bilateral carotid occlusion was abolished. The increase in aortic noradrenaline concentration during the occlusion was significantly attenuated by approximately 60% (P less than 0.01) after ADRX. 4. The increase in net renal noradrenaline output during bilateral carotid occlusion after ADRX was not different from that observed before ADRX. Similarly, the response of aortic systolic pressure and heart rate during the occlusion was unaffected by ADRX. Furthermore, the increase in net adrenal catecholamine output during the occlusion was not affected by ADRX itself. 5. From these results, we conclude that the increase in circulating catecholamines of adrenal origin during bilateral carotid occlusion is not a major determinant for the increases in aortic pressure and heart rate. The results suggest that these cardiovascular responses during the occlusion are mediated principally by neuronal noradrenaline released from peripheral sympathetic nerve terminals.

A differential effect of yohimbine on adrenal and neuronal catecholamine release during bilateral carotid occlusion in the dog.

This study reports on the effects of yohimbine and clonidine on the release of adrenal and renal catecholamines (epinephrine, E; norepinephrine, NE; and dopamine, DA) in response to bilateral carotid occlusion (BCO, 3 min) in vagotomized dogs anesthetized with sodium pentobarbital. The model used allowed us to simultaneously compare adrenal catecholamine secretion with neuronal NE release in the kidney. In control dogs, the net output (ng/min/g tissue) of adrenal E (70.5 +/- 19.7), NE (22.2 +/- 5.9) and DA (2.6 +/- 0.8) increased markedly (P less than 0.01) during BCO to a maximum level of 265.1 +/- 87.9, 97.4 +/- 30.6 and 10.5 +/- 3.2, respectively. Similarly, the net output (ng/min/g tissue) of renal NE (0.66 +/- 0.06) and DA (0.09 +/- 0.02) increased significantly (P less than 0.01) to 1.00 +/- 0.11 and 0.15 +/- 0.04, respectively. Aortic systolic pressure (mm Hg) (140.8 +/- 8.0) and heart rate (beats/min) (162.7 +/- 5.1) also increased (P less than 0.01) to 212.5 +/- 19.3 and 179.5 +/- 5.4, respectively. In dogs treated with yohimbine (0.3 mg/kg, i.v.), the net increase in adrenal catecholamine output was diminished by approximately 47% (P less than 0.05). In contrast, the net increase in renal NE output was potentiated by 41% (P less than 0.05). The net increase in heart rate was also enhanced significantly (P less than 0.01) in the presence of yohimbine. In dogs receiving clonidine (15 micrograms/kg, i.v.) the increases in net output of both adrenal and renal catecholamine were abolished. Similarly, pressor and heart rate responses were abolished in the presence of clonidine. The results indicate that yohimbine exerted a differential effect on renal sympathetic nerves (increase) and adrenal medullae (decrease) in modulating catecholamine release in response to BCO, while clonidine abolished both neural NE release and adrenal catecholamine secretion. This study suggests that a presynaptic alpha 2-adrenoceptor-mediated mechanism, the blockade of which enhances neural NE release at peripheral sympathetic nerve terminals in many tissues, may not be involved in the modulation of adrenal catecholamine secretion during BCO.