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PubMed1985

Testosterone administration to ovariectomized female rhesus monkeys (Macaca mulatta) reduces the frequency of pulsatile luteinizing hormone secretion.

In the male rhesus monkey testosterone (T) retards the frequency of intermittent LH secretion. The purpose of the present study was to determine whether this action of T is demonstrable in the female. Five ovariectomized rhesus monkeys, bearing indwelling cardiac catheters, were implanted s.c. on one or more occasions with T-containing Silastic capsules. Sequential blood samples were collected for 8 h every 10 min before T treatment and usually at 1, 2, 4, and 8 days thereafter. Plasma LH concentrations were measured in duplicate by radioimmunoassay and subsequently analyzed with a computerized algorithm. Sustained increments in circulating T (5-13 ng/ml) in ovariectomized monkeys resulted in a progressive reduction in LH pulse frequencies from approximately 1 pulse every 60 min before initiation of T treatment to 1 pulse every 100-150 min at 48 h thereafter. In most cases the deceleration in pulsatile gonadotropin secretion continued, and by 4-8 days of T treatment LH pulse frequencies as low as 1 pulse every 5 h were observed. The onset of the T-induced deceleration in LH pulse frequency was generally associated with an increase in LH pulse amplitude and with a decline in mean LH levels. This LH response in the female to T treatment was similar to that previously reported for male castrates.

Animals↗
PubMed1986

Outcome in children with normal growth following removal of a craniopharyngioma.

Ten children who had normal or excessive growth rates following surgical removal of a craniopharyngioma have been followed. Final adult heights for three were more than 2.5 standard deviations below the mean adult height for sex. Nine of the 10 children showed a deceleration in growth rate that occurred 1.5-6 years following surgery. The deceleration in linear growth did not appear to correlate with changes in weight gain, somatomedin-C, or the integrated insulin response to an oral glucose load. These results suggest that the mechanisms whereby some children with growth hormone deficiency have normal growth rates following neurosurgic procedures are complex. The authors recommend that these children have continued follow-up so that growth hormone therapy may be instituted when appropriate.

Body Height↗
PubMed1995

Effects of adenosine infusion on systolic and diastolic left ventricular function after coronary artery bypass surgery: evaluation by computer-assisted quantitative 2-D and Doppler echocardiography.

The effects of adenosine on central hemodynamics, ST-segment changes, and left ventricular (LV) systolic and diastolic function, determined by transesophageal 2-D and Doppler echocardiography, were investigated in 20 patients shortly after coronary surgery. After control measurements, adenosine was infused at incremental infusion rates (30, 60, and 120 micrograms.kg-1.min-1). Adenosine caused dose-dependent increases in heart rate (68.0 +/- 11.2-74.0 +/- 15.7 bpm), cardiac output (3.23 +/- 0.76-4.17 +/- 0.67 L/min), and stroke volume (48.8 +/- 12.5-56.7 L/min), and stroke volume (48.8 +/- 12.5-56.7 mL), decreases in arterial pressure (84.8 +/- 16.6-63.3 +/- 15.2 mm Hg), and systemic and pulmonary vascular resistances (1994 +/- 510-1106 +/- 309 and 209 +/- 54-116 +/- 58 dyne.s.cm-5, respectively), but no changes in cardiac filling pressures. The mean ST segment was slightly but significantly depressed by adenosine (from 0.003 to 0.019 mV). Analysis of LV wall motion showed that adenosine caused no changes in the global area ejection fraction (GAEF), the segmental area ejection fraction (SAEF), or in the SAEF/GAEF ratio, indicating that no regional wall motion abnormalities appeared. Maximum early and late diastolic flow rates (Emax, Amax), determined by mitral Doppler analysis, increased (from 30.1 +/- 14.8 to 40.1 +/- 24.1 and from 37.8 +/- 15.7 to 46.4 +/- 31.3 cm/s, respectively), as did the deceleration slope of the early diastolic filling (from -151 +/- 67 to -210 +/- 107 cm/s-2), whereas no changes were found in the ratio between Emax and Amax, the deceleration time of early diastolic filling, or the velocity time integrals of early or late diastolic filling.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1994

Influence of phenylephrine bolus administration on left ventricular filling dynamics in patients with coronary artery disease and patients with valvular aortic stenosis.

BACKGROUND: Left ventricular diastolic function is known to be impaired in patients with coronary artery disease and patients with valvular aortic stenosis. Phenylephrine is frequently administered as an intravenous bolus in these patients perioperatively to increase coronary perfusion pressure. Although this is common practice, there is no information about the effect of phenylephrine bolus administration on left ventricular filling dynamics. METHODS: Twenty patients with coronary artery disease (group 1), 15 patients with valvular aortic stenosis (group 2), and 10 subjects without cardiovascular disease (group 3, control) entered the study. Left ventricular filling was evaluated using transesophageal pulsed Doppler echocardiography before and after phenylephrine injection given to patients whose mean blood pressure has decreased by more than 20% (and was not higher than 90 mmHg). We recorded the transmitral blood flow velocity curve and measured peak early and peak atrial flow velocity, acceleration and deceleration time of the early flow velocity peak, and mitral valve diameter. We calculated the ratio of peak early to peak atrial flow velocity (PE/PA), acceleration and deceleration rate of the early flow peak, and peak filling rate. RESULTS: Phenylephrine effectively restored arterial pressure in all three groups. However, in group 1, phenylephrine administration resulted in a reduction of PE/PA, acceleration rate of the early flow peak, and peak filling rate from 1.25 (mean) to 0.75 (P < 0.001), 411 to 276 cm/s2 (P < 0.001), and 439 to 305 ml/s (P < 0.001), respectively. In contrast, in group 2, intravenous phenylephrine increased PE/PA, acceleration rate of the early flow peak, and peak filling rate from 0.76 to 0.97 (P < 0.001), 365 to 503 cm/s2 (P < 0.05), and 321 to 388 ml/s (P < 0.01), respectively. In the control subjects, phenylephrine caused a transient reduction of PE/PA and peak filling rate from 1.71 to 1.39 (P < 0.001) and 618 to 524 ml.s-1 (P < 0.001), respectively. CONCLUSIONS: Phenylephrine bolus administration causes an alteration of left ventricular filling in coronary artery disease patients that seems to be more marked than that seen in normal subjects. In patients with aortic stenosis no deleterious effects were observed in response to phenylephrine.

Adult↗
PubMed2005

Transcranial magnetic stimulation of the sensorimotor cortex alters kinaesthesia.

Tendon vibration is known to evoke perception of illusory movements, together with motor responses in the muscles antagonistic to those vibrated. In the present study, we assessed the perceptual and motor effects of transcranial magnetic stimulation of the sensorimotor cortex during illusions of hand movements evoked by vibration of wrist muscle tendons. The results showed that transcranial magnetic stimulation could accelerate or decelerate the illusory movements, depending on the site and intensity of magnetic stimulation. Whenever transcranial magnetic stimulation decelerated illusory movements, motor responses decreased, whereas whenever it accelerated illusory movements, motor responses increased. We conclude that motor responses associated with movement illusions have a cortical stage, because they are affected by experimentally induced disruption of activity in intracortical networks.

Adult↗
PubMed1996

A new scoring system, using Doppler transmitral diastolic measurement, identifies transient myocardial ischaemia.

In patients with acute transient myocardial ischaemia, changes in left ventricular filling produce alterations in transmitral diastolic flow velocity and isovolumic relaxation time. In this study a scoring system derived from isovolumic relaxation time and indices from transmitral flow velocity was used to evaluate perioperative transient myocardial ischaemia. Fifty three patients with known coronary artery disease or at risk were studied. Ischaemic events were assessed using Doppler transoesophageal echocardiography midoesophageal left ventricular four-chamber view planes. Diastolic Doppler ratios of peak early to atrial peak (E/A), deceleration time, deceleration rate and isovolumic relaxation time were scored using standard methods. An evaluation of peri-operative ischaemic events could be important for patients with a non-ischaemic cause for abnormal segmental wall motion, as the use of a two-dimensional scoring system has limitations. Acute changes in the Doppler ratio of peak early to atrial peak must be interpreted cautiously during surgery. Diastolic dysfunction commonly occurs during ischaemia and recognition of this may alter the approach to monitoring as well as to treatment.

Adult↗
PubMed1991

Left ventricular filling: relationship with arterial blood pressure, left ventricular mass, age, heart rate and body build.

The relationships of age, heart rate, body build and, in particular, of arterial blood pressure and left ventricular mass to several Doppler indexes of diastolic function were evaluated in a series of 80 subjects with a wide range of blood pressure levels (106-217/68-144 mmHg). Body build and age results were inversely correlated to the indexes, reflecting the early contribution to left ventricular filling, whereas the increase in heart rate was associated with an increase in late diastolic contribution. Strong correlations (in most instances, P less than 0.0001) were observed with arterial blood pressure and left ventricular mass: the increase of these parameters was associated with a decrease of early transmitral peak velocity (E peak) and of early filling fraction, with an increase of late diastolic transmitral peak velocity (A peak) and of A:E ratio and, finally, with an increase of both deceleration time of E peak and acceleration time to A peak. Blood pressure or left ventricular mass were also confirmed as strong predictors of nearly all the Doppler-derived diastolic indexes by stepwise multiple regression analysis. When the subjects were subdivided into quintiles according to diastolic blood pressure and the average values of the five subgroups were compared, age, heart rate and body build results were similar in the quintiles while diastolic blood pressure increased stepwise by 10 mmHg. Analysis of variance showed significant differences for all the indexes of left ventricular filling except deceleration time of and acceleration time to E peak (P less than 0.05 to P less than 0.0001) and almost all the echo-Doppler indexes showed a linear trend with diastolic blood pressure and left ventricular mass.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2000

Risk factors for severe esophageal and gastric lesions in term neonates: a case-control study. Groupe Francophone d'Hépato-Gastroentérologie et Nutrition Pédiatrique.

BACKGROUND: The purpose of this multicenter case-control study was to search for causes and risk factors related to the severe upper digestive tract lesions often seen in neonates. METHODS: Case patients were full-term neonates with endoscopically confirmed severe bleeding or ulcerative lesions of the esophagus and/or stomach. Matched control subjects were the next infant born in the same maternity unit who met the same criteria and had no clinical abnormality (and, for ethical reasons, no endoscopy). The analysis was based on 137 case-control pairs and considered data showing the mothers' medical and obstetric background, the infants' clinical status and laboratory results, feeding details, and the State and Trait Anxiety Inventory (STAI) questionnaire, which was used to assess the anxiety of the mothers. RESULTS: Cases and controls did not differ in any demographic or social factors. Antacid and anti-ulcer drugs were used significantly more frequently during the last month of pregnancy by case mothers than by control mothers (28% and 10%, respectively; P < 0.001). Mode of delivery was similar. Case infants more frequently experienced cardiac deceleration during labor and delivery (28% and 12.9%; P = 0.003). Breastfeeding at birth was less frequent for case infants (36% and 49%; P = 0.05). The mean trait anxiety scores did not differ between the two groups, but the mean state anxiety score was higher in case mothers. Multivariate logistic regression found that three factors were independently and significantly associated with esophageal and gastric lesions: use of antacid and antiulcer treatments (odds ratio [OR], 3.9; P < 0.001), cardiac deceleration (OR, 2.2; P = 0.03), and breast-feeding (OR, 0.5; P = 0.02). CONCLUSIONS: Antacid drug use by mothers during the last month of pregnancy was associated with esophageal and gastric lesions. Breast-feeding may play a protective role against severe lesions in neonates.

Antacids↗
PubMed1997

Beta-adrenergic stimulation enhances left ventricular diastolic performance in normal subjects.

To determine the effects of beta-adrenergic stimulation on transmitral Doppler echocardiography flow characteristics of left ventricular diastolic filling, we studied 10 healthy volunteers aged 23-31 years (mean age, 26.6 years) during intravenous infusion of isoprenaline in consecutive steps of 0.1, 0.2, 0.4, 0.75, and 1.5 micrograms/min (each for 15 min). Saline control infusion was given in the same manner in a crossover and blinded protocol. Compared with the infusion of placebo, stepwise increasing doses of isoprenaline caused a dose-related increase in early and late diastolic filling velocities and velocity-time integrals, a lengthening of the acceleration time, and a shortening of the deceleration and filling time. The chosen method proved highly sensitive, as statistically significant changes were detectable at the lowest dose of 0.1 microgram/min for all variables except velocity-time integral of late filling and deceleration time (> or = 0.2 microgram/min). The effects related to dose in a log-linear fashion except for the lengthening of the acceleration time (early ceiling), the increase of peak early filling velocity (increased steepness at higher doses), and the shortening of the filling time. Inclusion of the associated increases in heart rate and systolic blood pressure and the decrease in diastolic blood pressure blunted all treatment contrasts except for the increase of peak early filling velocity. In addition, the hemodynamics with respect to heart rate and loading conditions were not altered at low dosages of drug (< 0.4 microgram/min). Effects of at least the peak early filling velocity must be interpreted as an active adrenergically mediated myocardial relaxation process. These findings have potentially important clinical implications for this noninvasive, readily available, and convenient technique in clinical pharmacology, stress testing, and possibly therapeutic interventions in diastolic dysfunction in humans.

Adrenergic beta-Agonists↗
PubMed1999

Heart-rate variability effects of beta-adrenoceptor agonists (xamoterol, prenalterol, and salbutamol) assessed nonlinearly with scatterplots and sequence methods.

Full antagonists of the cardiac beta-adrenoceptor improve heart-rate variability (HRV) in humans; however, partial agonism at the beta2-adrenoceptor has been suggested to decrease HRV. We therefore studied the HRV effects of some partial agonists of the beta1- and beta2-adrenoceptors in normal volunteers. Under double-blind and randomised conditions (Latin square design), eight healthy volunteers received placebo; xamoterol, 200 mg (beta1-adrenoceptor partial agonist); prenalterol, 50 mg (beta1- and beta2-adrenoceptor partial agonist); salbutamol, 8 mg (beta2-adrenoceptor partial agonist); ICI 118,551, 25 mg (selective beta2-adrenoceptor antagonist); and combinations of each partial agonist with ICI 118,551. Single oral doses of medication (at weekly intervals) were administered at 22:30 h with HRV assessed from the overnight sleeping heart rates. HRV was determined by using standard time-domain summary statistics and two nonlinear methods, the Poincaré plot (scatterplot) and cardiac sequence analysis. On placebo, the sleeping heart rate decreased significantly, between 2 and 8 h after dosing. The heart rate with ICI 118,551 was unaltered. Xamoterol, prenalterol, and salbutamol increased the sleeping heart rate. ICI 118,551 blocked the heart-rate effects of salbutamol, attenuated those of prenalterol, but did not influence the xamoterol heart rate. The scatterplot (Poincaré) area was reduced by beta1-adrenoceptor (xamoterol), beta2-adrenoceptor (salbutamol), and combined beta1- and beta2-adrenoceptor (prenalterol) agonism. A reduction in scatterplot length followed salbutamol, prenalterol alone, and prenalterol in combination with ICI 118,551. The geometric analysis of the scatterplots allowed width assessment (i.e., dispersion) at fixed RR intervals. At higher heart rates (i.e., 25 and 50% of RR scatterplot length), dispersion was decreased after xamoterol, prenalterol, and prenalterol/ICI 118,551. Cardiac sequence analysis (differences between three adjacent beats; deltaRR vs. deltaRRn+1) assessed the short-term patterns of cardiac acceleration and deceleration; four patterns were identified: +/+ (a lengthening sequencing), +/- or -/+ (balanced sequences), and finally -/- (a shortening sequence). Cardiac acceleration or deceleration episodes (i.e., number of times deltaRR and deltaRRn+1 were altered in the same direction) were increased after salbutamol and prenalterol. In conclusion, partial agonism at either the cardiac beta1-adrenoceptor (xamoterol), beta2-adrenoceptor (salbutamol), and beta1- plus beta2-adrenoceptors (prenalterol) altered the autonomic balance toward sympathetic dominance in healthy volunteers; blockade of the beta2-adrenoceptor with the highly selective beta2-antagonist ICI 118,551 prevented the effects of salbutamol on HRV, attenuated the HRV effects of prenalterol, but had no effect on the actions of xamoterol. Agonism at both the beta1- and beta2-adrenoceptor reduced HRV in healthy subjects; the implications for the preventive use of the beta-adrenoceptor compounds in cardiovascular disease warrant further investigation.

Adrenergic beta-Agonists↗
PubMed1981

Injuries sustained from high velocity impact with water: an experience from the Golden Gate Bridge.

Over 720 persons are reported to have died jumping from the Golden Gate Bridge. A review of 100 consecutive autopsies showed that, in the majority of cases, massive pulmonary contusion, pneumothorax, laceration or perforation of the heart, great vessels, or lungs by displaced ribs were the causes of immediate death. Irreparable fractures of the liver or spleen were the most common abdominal injuries. The persons fatally injured appeared to have entered the water in a horizontal position, experiencing maximal deceleration. In contrast, six survivors entered the water feet first with more gradual deceleration. These survivors remained conscious but sustained similar injuries of lesser degree; only one sustained rib fractures. Fifty per cent had fractures of the liver or spleen requiring operative therapy. Fifty per cent sustained lung contusions and subsequent pneumothoraces. Suspicion of underlying injuries to the liver, spleen, and lungs is essential during resuscitation of those who survive impact with water.

Abdominal Injuries↗
PubMed1982

Embolotherapy of a ruptured internal mammary artery secondary to blunt chest trauma.

A unique case of traumatic rupture of the internal mammary artery secondary to blunt deceleration injury of the chest is reported. The injury, which produced changes consistent with great vessel disruption on the plain chest radiograph, was treated by percutaneous transcatheter embolization of Gianturco steel coils. The importance of surveying all arteries visualized during thoracic aortography in patients with widened mediastinum following deceleration injury to the chest is reinforced. Embolotherapy of this noncritical chest wall vessel is demonstrated.

Accidents↗
PubMed1993

An analysis of accidental free falls from a height: the 'spring break' syndrome.

Vertical deceleration injuries represent a distinct form of urban blunt trauma. Mechanisms of injury differ from those of horizontal vehicular trauma, and severity primarily depends on velocity of impact. We describe 33 free-fall injuries in adults occurring under purely nonintentional circumstances at a popular college "spring break" resort. Patterns of injuries were found to differ significantly from previously reported patterns of injuries sustained by adults from both accidental and intentional vertical deceleration.

Accidental Falls↗
PubMed1994

A critical analysis of the fatal injuries resulting from the Continental flight 1713 airline disaster: evidence in favor of improved passenger restraint systems.

OBJECTIVE: To examine the mechanisms of injury and death in a commercial airline disaster and to propose preventative safety measures based on this analysis. DATA SOURCE: Denver County Coroner's Office and the National Transportation Safety Board. STUDY SELECTION: Those patients suffering fatal injuries as a result of the Continental Flight 1713 Airline crash. DATA EXTRACTION: Autopsy records from the Denver County Coroner's Office were reviewed with the causes of death determined. In many instances there was significant injury to more than one anatomic region in a single individual, each analyzed independently. DATA SYNTHESIS: There were 28 fatalities: nine died of mechanical asphyxiation, one of a penetrating cranial injury, and 18 of blunt trauma. The blunt injuries were remarkably similar to the deceleration injuries seen in high-speed motor vehicle crashes. Head trauma was the most common fatal blunt injury, followed by injuries to the chest and the abdomen. Thirty-six percent of the head injuries and 27% of the chest injuries had associated cervical and thoracic spine fractures, respectively. Analysis revealed a marked similarity in injury pattern sustained by seatmates, with a high incidence of fatal and serious injuries suffered by those passengers sitting in the front half of the airplane. CONCLUSIONS: Fatal blunt injury secondary to deceleration forces was the most common cause of death seen in this analysis. The use of a lap belt restraint system alone is not adequate to protect passengers against these forces as shown convincingly in the automotive industry literature. What impact a better passenger restraint system may have had on survival in this disaster is unknown, however, at a minimum, it would have significantly improved survival for 6 of 28 passengers dying of isolated blunt head trauma. Minor alterations in aircraft design (secure bolting of passenger seats to the airplane superstructure) and passenger restraints (3-point lap and shoulder harness system) is proposed to positively influence survival during an airplane crash at negligible increased airline expense or passenger inconvenience.

Accidents, Aviation↗
PubMed1994

Comparative efficacy of two sonographic measurements for the detection of aberrations in the amniotic fluid volume and the effect of amniotic fluid volume on pregnancy outcome.

OBJECTIVE: To determine in pregnant women with preterm labor the relative efficacy of the amniotic fluid index (AFI) and the two-diameter pocket to detect abnormalities in amniotic fluid volume (AFV), and to relate these findings to pregnancy outcome. METHODS: Fifty-seven healthy women with preterm labor underwent amniocentesis in the third trimester to detect subclinical chorioamnionitis and assess fetal lung maturity. The AFV was estimated by the AFI and two-diameter-pocket methods, then confirmed by a dye (aminohippurate sodium)-dilution technique. Each labor was evaluated for severe variable decelerations requiring amnioinfusion, fetal distress resulting in cesarean delivery, and a 5-minute Apgar score below 7. RESULTS: Using fluid volume confirmed by dye dilution, the AFI correctly diagnosed AFV as low (less than 500 mL) in only two of 23 (8.7%) patients, compared to 14 of 23 (61%) for the two-diameter pocket (P < .001). Fetal distress requiring cesarean delivery occurred significantly more often in the hydramnios group (three of six) compared to those with normal AFV (one of 23) (P < .03), and approached significance in the oligohydramnios group (two of 21) (P = .056). There were no significant differences among the three patient groups regarding the need for amnioinfusion for severe variable decelerations or the occurrence of 5-minute Apgar scores below 7. CONCLUSIONS: Compared to the AFI, the two-diameter pocket is a superior sonographic measurement for the detection of oligohydramnios. In an otherwise low-risk pregnancy with preterm labor, oligohydramnios is associated with no greater risk for an adverse outcome than is a normal AFV.

Adult↗
PubMed2005

ACOG Committee Opinion. Number 326, December 2005. Inappropriate use of the terms fetal distress and birth asphyxia.

The Committee on Obstetric Practice is concerned about the continued use of the term "fetal distress" as an antepartum or intrapartum diagnosis and the term "birth asphyxia" as a neonatal diagnosis. The Committee reaffirms that the term fetal distress is imprecise and nonspecific. The communication between clinicians caring for the woman and those caring for her neonate is best served by replacing the term fetal distress with "nonreassuring fetal status," followed by a further description of findings (eg, repetitive variable decelerations, fetal tachycardia or bradycardia, late decelerations, or low biophysical profile). Also, the term birth asphyxia is a nonspecific diagnosis and should not be used.

Asphyxia Neonatorum↗
PubMed1997

Prediction of the crankshaft phenomenon by peak height velocity.

STUDY DESIGN: Retrospective review. OBJECTIVES: To evaluate the relation of the peak height velocity with the occurrence of the crankshaft phenomenon after posterior arthrodesis and instrumentation in idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Although patients with closed triradiate cartilages are unlikely to exhibit the crankshaft phenomenon after a posterior spinal fusion and instrumentation, open triradiate cartilages do not necessitate that crankshafting will occur. Less than half of patients with idiopathic scoliosis and open triradiate cartilages will exhibit the crankshaft phenomenon. METHODS: The authors reviewed 43 patients with idiopathic scoliosis who were Risser 0 at the time of posterior spinal fusion. Twenty-three patients had open triradiate cartilages and twenty had closed. The timing of peak height velocity was identified. RESULTS: All patients with closed triradiate cartilages were beyond their peak height velocity at the time of surgery. Among those with open triradiate cartilages, 8 were operated on before or during their peak and 15 were operated on afterward. All patients fused before or during the peak crankshafted. Two of the fifteen patients fused after the peak crankshafted. In one, it was low grade. In the other, it appears that the fusion blunted the peak height velocity to a point at which it was unidentifiable. CONCLUSIONS: In patients with open triradiate cartilages, surgery performed before or during the peak height velocity is a strong predictor of the crankshaft phenomenon, and later surgery is a strong negative predictor of the crankshafting (P = 0.000009). Isolated posterior fusion before the height velocity decelerates results in the crankshaft phenomenon, whereas fusion during the deceleration phase does not.

Adolescent↗