Second-trimester sex hormone-binding globulin and subsequent development of pre-eclampsia.

OBJECTIVE: To investigate whether maternal plasma sex hormone-binding globulin (SHBG) concentrations are reduced in women who subsequently develop pre-eclampsia. METHODS: This was a cross-sectional study, carried out at antenatal clinics in seven hospitals in and around London. Healthy women underwent uterine artery Doppler velocimetry as a screening method for pre-eclampsia at 22-24 weeks of gestation. The first group (408 women) had normal uterine artery Doppler waveforms (mean uterine artery pulsatility index (PI) below 1.6). The second group (274 women) had increased impedance to flow in the uterine arteries (mean PI above the 95th centile, 1.6). Maternal plasma SHBG concentrations were measured retrospectively using a competitive chemiluminescent immunoassay. Pre-eclampsia was as defined by the International Society for the Study of Hypertension in Pregnancy. RESULTS: Plasma SHBG concentrations in the 80 (11.7%) women who subsequently developed pre-eclampsia were significantly lower than in the 585 (85.8%) women with normal pregnancy outcomes (median 336, range 142-674 nmol/l vs. median 336, range 142-674 nmol/l, p = 0.001). There was a strong correlation between SHBG concentrations and body mass index (r =-0.232246, p < 0.0001). There were no significant differences in maternal plasma SHBG concentrations in women with abnormal uterine artery Doppler (n = 274) compared with controls (n = 408) (median 324, range 101-635 nmol/l vs. median 336, range 142-674 nmol/l, p = 0.09). CONCLUSION: Maternal plasma SHBG concentrations are reduced in women who subsequently develop pre-eclampsia.     

The influence of partnership centrality on organizational perceptions of support: a case study of the AHLN structure

Background  

Knowledge of the structure and character of inter-organizational relationships found among health promotion organizations is a prerequisite for the development of evidence-based network-level intervention activities. The Alberta Healthy Living Network (AHLN) mapped the inter-organizational structure of its members to examine the effects of the network environment on organizational-level perceptions. This exploratory analysis examines whether network structure, specifically partnership ties among AHLN members, influences organizational perceptions of support after controlling for organizational-level attributes.     

Repair of large midline incisional hernias with polypropylene mesh: Comparison of three operative techniques

Polypropylene mesh is widely used for the reconstruction of incisional hernias that cannot be closed primarily. Several techniques have been advocated to implant the mesh. The objective of this study was to evaluate, retrospectively, early and late results of three different techniques, onlay, inlay, and underlay. The records of 53 consecutive patients with a large midline incisional hernia — 25 women and 28 men, mean age 60.4 (range 28–94) — were reviewed. Polypropylene mesh was implanted using the onlay technique in 13 patients, inlay in 23 patients, and underlay in 17 patients. Either the greater omentum or a polyglactin mesh was interponated between the mesh and the viscera. The records of these 53 patients were reviewed with respect to: size and cause of the hernia, pre- and postoperative mortality and morbidity, with special attention to wound complications. Patients were invited to attend the outpatient clinic at least 12 months after implantation of the mesh for physical examination of the abdominal wall. Postoperative complications occurred in 14 (26.4%) patients. The onlay technique had significantly more complications, as compared to both other techniques. Reherniation occurred in 15 (28.3%) patients. The reherniation rate of the inlay technique was significantly higher than after the underlay technique (44% vs 12%, P=0.03) and tended to be higher than the onlay technique (44% vs 23%, P=0.22). Repair of large midline incisional hernias with the use of a polypropylene mesh carries a high risk of complications and has a high reherniation rate. The underlay technique seems to be the better technique.     

Relation between magnesium and potassium concentrations in myocardium, skeletal muscle, and mononuclear blood cells.

Potassium and magnesium were measured in 26 cardiac surgery patients (right atrial appendage), 23 autopsy subjects (right atrial appendage, left ventricular free wall, and skeletal muscle), and 9 healthy volunteers (mononuclear blood cells) to determine whether there was a relation between these two ions in the tissues measured. In the cardiac surgery patients, the potassium and magnesium concentrations were 46.35 +/- 3.89 and 4.40 +/- 0.58 (mean +/- SD, mumol/g wet weight tissue), respectively, and were significantly correlated (r = 0.54, P = 0.005). In the autopsy group, the respective concentrations were: for right atrial appendage, 30.54 +/- 10.18 and 3.66 +/- 0.70 mumol/g (r = 0.38, P = 0.14); left ventricular free wall, 60.69 +/- 17.93 and 7.74 +/- 1.73 mumol/g (r = 0.92, P = 0.0001); and skeletal muscle, 93.05 +/- 20.49 and 8.64 +/- 2.06 mumol/g (r = 0.91, P = 0.0001). In the healthy volunteer group, the results for potassium and magnesium in mononuclear blood cells were 42 +/- 9.9 and 3.99 +/- 0.70 fmol/cell, respectively (r = 0.94, P = 0.0001). Thus, potassium and magnesium concentrations were significantly correlated in all the tissues measured.     

Critical appraisal and further development of the methodology for open circuit calorimetry in neonates.

A non-invasive technique for open circuit calorimetry based on a Vickers 79 incubator as the gas collection chamber was developed and evaluated. The technique, which involved drawing air from the incubator hood at 11 1/min for gas analysis, did not have a significant cooling effect on the infant and the noise levels within the incubator did not exceed current safety standards. A new technique for checking the calibration of the whole system was developed as the traditional alcohol burn method proved unsatisfactory. Either pure oxygen or carbon dioxide were fed into the incubator hood at controlled physiological rates using a calibrated throttling valve. Over a number of calibration checks the mean error of the system proved to be +/- 4.3% for oxygen and +/- 4.45% for carbon dioxide. Less than a fifth of this error was attributable to the pump and flow meter. When oxygen is introduced to the system at a constant physiological rate it takes 30 min for a plateau to be reached. Therefore it is recommended that this system is used when readings are to be taken in a steady state situation or data is to be cumulated over a long period of time such as in an energy balance study. A run in period of 30 min before collecting data is essential. It is recommended that a calibration check is performed before each study.     

Dose-Response Characteristics of Spinal Bupivacaine in Volunteers: Clinical Implications for Ambulatory Anesthesia

Background: Small doses of bupivacaine may be a reasonable choice for spinal anesthesia for patients having ambulatory surgery. However, few dose-response data are available to guide the selection of reasonable doses of bupivacaine for different ambulatory procedures.

Methods: Eight volunteers per group were randomized to receive 3.75, 7.5, or 11.25 mg of 0.75% bupivacaine with 8.25% dextrose in a double-blind manner. Sensory block was assessed with pinprick, transcutaneous electrical stimulation equivalent to surgical incision at the ankle, knee, pubis, and umbilicus, and with duration of tolerance to pneumatic thigh tourniquet. Motor block at the quadriceps and gastrocnemius muscles was assessed with isometric force dynamometry. Times until recovery from spinal anesthesia were recorded. Dose-response relationships were determined by linear regressions. Mean (95% confidence intervals) for durations of sensory and motor block per milligram of bupivacaine administered were calculated from linear regressions.

Results: Significant dose-response relationships (P < 0.006) were determined for sensory block, motor block, and time until recovery (R from 0.6 to 0.9). Within the range of doses studied, each additional milligram of bupivacaine was associated with an increase in duration of tolerance to transcutaneous electrical stimulation of 10 (7 to 13) min, an increase in tolerance to tourniquet of 7 (2 to 11) min, an increase in duration of motor block of 8 (5 to 12) min, and an increase in time until recovery of 21 (17 to 25) min.     

Hyperexcitability associated with localizable lesions in epileptic patients

Intracellular recordings from neurons were carried out in cortical slices obtained from tissue removed from patients suffering from intractable seizures. The patients were divided into two groups based on the presence or absence of an anatomical abnormality that could be imaged preoperatively. The lesion or its surround was the presumptive epileptogenic area. The tissue removed from the patients without lesions was removed either for biopsy purposes or for access to epileptic tissue and was not considered epileptogenic. All neurons from patients without an imageable lesion, and some (19%) from patients with an imageable lesion, responded to orthodromic stimuli with a sequence of synaptic excitation followed by inhibition; these properties resembled those of normal rodent cortical slices. Different responses, classified as abnormal, were observed in 81% of the neurons in tissue specimens obtained near lesions. The most common was prolonged synaptic excitation with no noticeable inhibition, even at high stimulus strengths. In three resections, long latency all-or-none depolarization shifts were observed that resemble the classic paradoxical depolarization shift seen in in vivo extracellular recordings. Loss of specific inhibitory systems within the cortex may contribute in part to these abnormal responses.