Variable expression of the Fragile X Mental Retardation 1 (FMR1) gene in patients with premature ovarian failure syndrome is not dependent on number of (CGG)n triplets in exon 1

BACKGROUND

Increased expression of the Fragile X Mental Retardation 1 (FMR1) gene in blood cells has been claimed to be associated with variable (CGG)(n) triplet numbers in the 5' untranslated region of this gene. Increased CGG triplet numbers, including that of the so-called premutation range (n= 55-200), were shown to have a risk of <26% to impair ovarian reserve leading to primary ovarian insufficiency and premature ovarian failure (POF).

METHODS

DNA and RNA samples were isolated from 74 patients with idiopathic POF to evaluate quantitatively the expression of FMR1 in leukocytes and CGG triplet number on FMR1 gene alleles. mRNA levels were normalized and compared with those of control women. Expression of the encoded protein (FMRP) was analysed by immunohistochemistry on ovarian biopsy tissue sections.

RESULTS

A large variance of the FMR1 transcript level was found in the leukocyte RNA samples, but only in patients with POF, and this variability did not correlate to variance of CGG triplet numbers found on both FMR1 alleles (19 < n > 90). During normal folliculogenesis, FMRP is predominantly expressed in granulosa cells.

CONCLUSIONS

Our data suggest that FMR1 expression during human folliculogenesis is probably a quantitative trait. Proper function of FMRP in granulosa cells seems to depend on an optimal transcript level. All women with CGG triplet numbers outside the range associated with normal folliculogenesis (26 < n > 34) are therefore expected to have a relaxed FMR1 transcription control. FMR1 transcript levels in leukocytes might therefore be diagnostic for altered FMRP levels in granulosa cells, which will affect the process of folliculogenesis.

Post-resuscitation haemodynamics in a novel acute myocardial infarction cardiac arrest model in the pig

BACKGROUND AND OBJECTIVES

Although a considerable amount of promising experimental research has been performed on cardiopulmonary resuscitation, clinical data indicate an ongoing limited outcome in human beings. One reason for this discrepancy could be that experimental studies use healthy animals whereas most human beings undergoing cardiopulmonary resuscitation suffer from acute or chronic myocardial dysfunction. To overcome this problem, we sought to develop a new model of myocardial infarction, that is easy to perform in all kind of laboratories and compromises on the myocardial function significantly.

METHODS

Following approval by the local authorities, 14 domestic pigs were instrumented for measurement of arterial, central venous, left atrial and left ventricular pressures. Myocardial infarction was induced in eight pigs by clipping the circumflex artery close to its origin from the left coronary artery (infarction group; n = 8). Six animals (no infarction group, n = 6) served as no-infarct controls. Following a 4-min period of cardiac arrest, internal cardiac massage was performed in these two groups, and haemodynamics were recorded during the first 30 min of reperfusion.

RESULTS

All animals were resuscitated successfully. Compared to the no-infarction group, the infarction group showed significantly decreased myocardial contractility, coronary perfusion pressure and cardiac index (30 min after restoration of spontaneous circulation: infarction group: 57 +/- 7 and 89 +/- 19 mL min-1 kg-1 in the no-infarction group; mean +/- SD; P < 0.05) during reperfusion. Two animals from the infarction group (25%), but none of the animals in the no-infarction group, died during the reperfusion period.

CONCLUSION

These data demonstrate that clipping of the circumflex artery leads to a reduced myocardial performance after successful resuscitation, whereas the rate of restoration of spontaneous circulation is not reduced. Therefore, this set-up provides a reproducible model for future studies of post-resuscitation haemodynamics and treatment.

Desflurane reduces the effective therapeutic infusion rate (ETI) of cisatracurium more than isoflurane, sevoflurane, or propofol

PURPOSE

The present study investigated the interaction between the cumulative dose requirements of cisatracurium and anesthesia with isoflurane, sevoflurane, desflurane or propofol using closed-loop feedback control.

METHODS

Fifty-six patients (18-85 yr, vitrectomies of more than one hour) were studied. In the volatile anesthetics groups, anesthesia was maintained by 1.3 MAC of isoflurane, sevoflurane or desflurane; in the propofol group, anesthesia was maintained by a continuous infusion of 6-8 mg.kg(-1).hr(-1) propofol. After bolus application of 0.1 mg.kg(-1) cisatracurium, a T1%-level of 10% of control level (train-of-four stimulation every 20 sec) was maintained using closed-loop feedback controlled infusion of cisatracurium. The effective therapeutic infusion rate (ETI) was estimated from the asymptotic steady-state infusion rate Iss. The Iss was derived from fitting an asymptotic line to the measured cumulative dose requirement curve. The ETI of the different groups was compared using Kruskal-Wallis- test, followed by rank sum test, corrected for the number of comparisons, P <0.05 was regarded as showing significant difference.

RESULTS

ETI in the isoflurane group was 35.6 +/- 8.6 microg.m(-2).min(-1), in the sevoflurane group 36.4+/- 11.9 microg m(-2).min(-1), in the desflurane group 23.8 +/- 6.3 microg.m(-2).min(-1). The ETI of the volatile anesthetic groups were all significantly lower than the ETI in the propofol group at 61.7 +/- 25.3 microg.m(-2).min(-1) (P <0.002). The ETI in the desflurane group was significantly lower than in all other groups (P <0.02).

CONCLUSION

In comparison to propofol, isoflurane, sevoflurane and desflurane reduce the cumulative dose requirements of cisatracurium to maintain a 90% neuromuscular blockade by 42%, 41% and 60%, respectively.

Awareness during laryngoscopy and intubation: quantitating incidence following induction of balanced anesthesia with etomidate and cisatracurium as detected with the isolated forearm technique

STUDY OBJECTIVE

To measure the incidence of awareness during induction of anesthesia with etomidate and fentanyl, and to model its frequency as a function of dose of etomidate.

DESIGN

Prospective cohort study.

SETTING

Anesthesia department of a university hospital.

PATIENTS

30 ASA physical status I, II, and III patients undergoing elective general surgery.

INTERVENTIONS

Patients were assigned to one of three groups of etomidate (0.2 mg/kg, 0.3 mg/kg, 0.4 mg/kg) and received fentanyl (2 microg/kg) and 2 x ED(95) of cisatracurium (0.1 mg/kg). Neuromuscular block was monitored with a peripheral nerve stimulator. Intubation was performed after maximum T(1)-depression. To identify awareness, the isolated forearm technique (IFT) was used. The IFT was performed by prompting the patient every 20 seconds. Only a verified response was considered a positive IFT response. Anesthesia was maintained with isoflurane in oxygen/air and fentanyl.

MEASUREMENTS AND MAIN RESULTS

Maximum neuromuscular block occurred after 352 +/- 96 seconds and intubation was performed 424 +/- 86 seconds after loss of consciousness (LOC). Awareness was dose dependent: 80% of patients receiving 0.2 mg/kg etomidate, 70% of patients receiving 0.3 mg/kg etomidate, and 20% of patients receiving 0.4 mg/kg etomidate had a positive IFT response. Awareness occurred in one patient 3 minutes after LOC, in 65% during laryngoscopy, and in 30% within the following 120 seconds. One patient had explicit recall without finding awareness unpleasant. Hemodynamic parameters did not differ between patients with a positive or a negative IFT response.

CONCLUSIONS

The incidence of awareness during bolus induction can be modeled as dose dependent. However, when combining a short-acting induction drug and a delayed-onset neuromuscular blocker, the continuous infusion of the hypnotic drug may prevent awareness during induction.

Stress hormones in accident patients studied before admission to hospital

OBJECTIVE

To assess stress hormone response in traumatised patients studied at the site of injury and on their way to hospital.

METHODS

The study was prospective. Blood samples were taken from 77 patients immediately after the arrival of the emergency physician at the site of the accident (t1) and shortly before patients' admission to hospital (t2). Plasma concentrations of beta endorphin, cortisol, adrenocorticotrophic hormone (ACTH), prolactin, and growth hormone were measured.

RESULTS

Trauma in out-of-hospital patients resulted in remarkably increased concentration of growth hormone within minutes. ACTH, cortisol, and prolactin were only moderately increased. No significant correlations were found between hormone levels and blood pressure or heart rate. The plasma ACTH concentration was significantly lower before admission to hospital than immediately after the accident. Plasma cortisol, prolactin, and growth hormone concentrations were not significantly different between the two points of observation. In samples taken immediately after the accident (t1), there was a positive correlation between both beta endorphin and prolactin and the injury severity score, whereas cortisol levels were negatively correlated with injury severity score, suggesting impaired cortisol release from the adrenal cortex after severe injury. At t1 ACTH was correlated with cortisol and beta endorphin. Patients with head injuries had hormone concentrations similar to those without head injuries but with a similar injury severity score from injuries in other parts of the body.

CONCLUSIONS

Lower cortisol concentrations in the very severely injured might be due to failure of the adrenal cortex to respond normally to ACTH stimulation. Growth hormone seems to play a major role in the response to trauma, reflecting an immediate stress response.