Haemodynamic profiles of etomidate vs propofol for induction of anaesthesia: a randomised controlled trial in patients undergoing cardiac surgery

Background

Etomidate is frequently selected over propofol for induction of anaesthesia because of a putatively favourable haemodynamic profile, but data confirming this perception are limited.

The in vitro fertilisation programme at Tygerberg Hospital and the University of Stellenbosch. Five years' experience, April 1983-January 1988

The results of the in vitro fertilisation programme at Tygerberg Hospital for the period April 1983 to January 1988 are presented. Of the 1117 laparoscopies performed, 825 patients reached the transfer stage. A live-birth rate of 9.3% was achieved. The pregnancy rate after transfer of 4 embryos was 25.9% compared with 15.4% after 2 embryos and 10.8% after 3 embryos (P = less than 0.0001). The multiple pregnancy rate was 2.8% in the group receiving 2 embryos and 11.7% and 10.4% in those receiving 3 and 4 embryos, respectively. Of the 77 successful pregnancies (90 babies), 1 baby died at 34 weeks' gestation as the result of abruptio placentae due to preeclampsia and 1 cot death occurred. The only congenital abnormality encountered was a cleft palate.     

Cloning and characterization of Ca(2+)-dependent and Ca(2+)-independent PKCs expressed in Aplysia sensory cells

We isolated cDNA clones from an Aplysia sensory-cell library encoding two isoforms of protein kinase C (PKC). Several isozyme-specific regions are conserved in the Aplysia kinases, notably the variable regions V5 in the Ca(2+)-dependent PKC (Apl I) and V1 in the Ca(2+)-independent PKC (Apl II). Neuronal proteins with the properties expected of these two isoforms can be identified with antibodies raised against peptides synthesized from the amino acid sequences deduced from the clones. Sacktor and Schwartz (1990) measured the proportion of kinase activity that can be translocated to membrane in Aplysia sensory neurons and ganglia by stimuli that produce the presynaptic facilitation underlying behavioral sensitization. Much less Apl I and Apl II are translocated, suggesting that still other isoforms of PKC exist in these cells.     

Ultrasensitive analysis of the intestinal absorption and compartmentalization of aluminium in uraemic rats: a 26Al tracer study employing accelerator mass spectrometry

BACKGROUND: Developments in accelerator mass spectrometry (AMS) now permit the determination of femtogram amounts of 26Al in blood and in various tissues with good precision and free of external contamination. METHODS: In the present study we used trace quantities of 26Al to investigate the intestinal absorption and compartmentalization of aluminium in rats with renal failure (Nx, 5/6 nephrectomy) and in pair- fed controls (C). Single oral doses of 20 ng 26Al were administered to six animals in each group and, subsequently, 24-h post-load 26Al was analysed in serum, urine, bone, liver, and spleen by means of AMS. RESULTS: Serum concentrations of 26Al were significantly lower in uraemic rats compared to controls, whereas urinary excretion was comparable (Nx, 7.11 +/- 5.78 pg/day vs C, 9.46 +/- 6.10 pg/day), suggesting a higher fraction of ultrafiltrable serum 26Al in uraemia. The target tissues of cellular transferrin-mediated 26Al uptake, liver and spleen, tended to show a larger degree of aluminium accumulation in controls (0.26 +/- 0.31 pg/g vs Nx, 0.14 +/- 0.10 pg/g and 0.37 +/- 0.27 pg/g vs Nx, 0.25 +/- 0.27 pg/g respectively). In contrast, in bone, a site of extracellular aluminium deposition, 26Al concentrations were more elevated in uraemia (1.22 +/- 0.59 pg/g vs C: 0.68 +/- 0.30 pg/g). Estimated total 26Al accumulation in all measured target tissues was significantly higher in uraemic rats (28.15 +/- 9.90 pg vs C: 17.03 +/- 7.03 pg) and total recovery of 26Al from tissue and urine was 26.58 +/- 6.74 pg in controls and 35.75 +/- 7.03 pg in uraemic animals, suggesting a fractional absorption of 0.133% and 0.175% respectively. CONCLUSIONS: Our data suggest that fractional absorption from a dietary level dose of 26Al is about 0.13%. Compartmentalization occurs in transferrin-dependent target tissues such as liver and spleen; however, in quantitative terms extracellular deposition in bone is more important. Uraemia has a significant effect on the intestinal absorption and compartmentalization of aluminium. It enhances fractional absorption and increases subsequent extracellular deposition of aluminium in bone. However, at the same time uraemia does not increase transferrin-dependent cellular accumulation of aluminium in liver and spleen.      

Human preovulatory oocytes have a higher sperm-binding ability than immature oocytes under hemizona assay conditions: evidence supporting the concept of "zona maturation"

OBJECTIVE: The purpose of this study was to investigate the sperm-binding potential of human oocytes at different stages of nuclear maturation under hemizona assay (HZA) conditions. DESIGN: This was a prospective study designed in a blinded fashion. SETTING: Academic research environment approved by the Institutional Review Board. PATIENTS: Surplus oocytes, donated by patients undergoing in vitro fertilization therapy after gonadotropin stimulation, were analyzed. Semen from a fertile donor was used in all assays. INTERVENTIONS: Five groups of oocytes were considered: (1) immature, prophase I; (2) metaphase I; (3) metaphase II; (4) inseminated, unfertilized metaphase II; and (5) immature, prophase I oocytes matured in vitro to metaphase II. Oocytes were stored in salt solution (pH 7.2) and microbisected before assay. MAIN OUTCOME MEASURE(s): Tight binding of sperm to the zona pellucida under HZA conditions was evaluated after 4 hours of gametes coincubation. RESULTS: Metaphase II oocytes (groups 3 and 4) had significantly higher binding than other groups (P = 0.0001). The mean value of the difference between the two halves (hemizona) was not significant, thus showing a small intra-assay variation for all maturational stages. CONCLUSIONS: Full meiotic competence of human oocytes is associated with an increased zona pellucida-binding potential.     

S-Adenosylhomocysteine, but not homocysteine, is toxic to yeast lacking cystathionine β-synthase

Elevated plasma homocysteine is associated with a variety of diseases in humans including coronary heart disease, stroke, peripheral vascular disease, and birth defects. However, the mechanism by which plasma homocysteine affects cells is unknown. We have examined the growth of isogenic wild-type and cystathionine beta-synthase (CBS) deficient yeast in response to homocysteine and its immediate metabolic precursor, S-adenosylhomocysteine (SAH). CBS deficient yeast export significantly more homocysteine into the media than wild-type yeast and have elevated internal pools of homocysteine and SAH. We found that 5 mM homocysteine added to the media had very little effect on the growth of wild-type or CBS deficient yeast, although intracellular homocysteine concentrations increased five- to tenfold. In contrast, as little as 25 microM S-adenosylhomocysteine inhibited the growth of CBS deficient yeast, but had no effect on wild-type yeast. Measurements of the intracellular S-adenosylmethionine (SAM) and SAH indicate that CBS deficient yeast contain reduced SAM/SAH ratios relative to wild-type, and this ratio is further reduced by adding SAH to the media. Growth inhibition by SAH in CBS deficient yeast can be totally reversed by addition of SAM to the media, indicating that the ratio and not absolute level is critical for cell growth. These results suggest that CBS plays a key role in the regulation of the SAM/SAH ratio inside cells and that excessive perturbations of this ratio can inhibit growth. We hypothesize that elevated extracellular homocysteine present in humans may reflect an altered intracellular SAM/SAH ratio and that this may be related to disease pathogenesis.     

Treatment of giant papillary conjunctivitis with cromolyn sodium.

We evaluated the efficacy of cromolyn sodium in the management of contact lens patients with GPC. Fourteen of 20 patients (70%) with moderate to severe giant papillary conjunctivitis (GPC) were able to continue wearing contact lenses with the use of 4% sodium cromolyn eye drops. These patients had all failed to stay symptom free with our standard method of treatment (i.e., discontinuing contact lens wear for 1-2 weeks; improving lens care; and refitting with different lens designs and/or polymers). This study examined the indications, therapeutic regimen, complications, and patient response to the use of sodium cromolyn in contact lens patients with GPC.