In vivo (31)P magnetic resonance spectroscopy and morphometric analysis of the perfused vascular architecture of human glioma xenografts in nude mice.

The relationship between the bioenergetic status of human glioma xenografts in nude mice and morphometric parameters of the perfused vascular architecture was studied using (31)P magnetic resonance spectroscopy (MRS), fluorescence microscopy and two-dimensional digital image analysis. Two tumour lines with a different vascular architecture were used for this study. Intervascular distances and non-perfused area fractions varied greatly between tumours of the same line and tumours of different lines. The inorganic phosphate-nucleoside triphosphate (P(i)/NTP) ratio increased rapidly as mean intervascular distances increased from 100 microm to 300 microm. Two morphometric parameters - the percentage of intervascular distances larger than 200 microm (ivd200) and the non-perfused area fraction at a distance larger than 100 microm from a nearest perfused vessel (area100), - were deduced from these experiments and related to the P(i)/NTP ratio of the whole tumour. It is assumed that an aerobic to anaerobic transition influences the bioenergetic status, i.e. the P(i)/NTP ratio increased linearly with the percentage of ivd200 and the area100.     

A postoperative analysis of the patient''s view of anaesthesia in a Netherlands'' teaching hospital

A postoperative questionnaire was used in 129 patients who had undergone a wide range of surgical procedures in order to investigate their personal experience of anaesthesia. The most frequent complaints were of feeling cold on waking up, sore throat, vomiting and muscle pains, all of which are capable of reduction by a change in anaesthetic technique. The total number of patients who had one or more complaints was 107 (82.9%). More than a third of the patients were afraid of the anaesthetic, as distinct from the operation. Most had received a pre-operative visit from the anaesthetist which was greatly appreciated. A few patients believed they could have been better informed of possible sequelae. More than 30% were not visited by the surgeon before the operation. A routine postoperative interview, using a preformulated questionnaire, is a good way to assess and maintain a high quality of anaesthesia.     

Modulation of histamine release by rat peritoneal mast cells in a superfusion set-up.

A new method is presented for studying mediator release in isolated peritoneal cells of the rat. Using a superfusion technique, cells can be maintained in a continuously cleared medium. Cells were stimulated with antigen, compound 48/80 or A23187 to characterize this preparation. In addition, inhibitory effects of theophylline, isoprenaline and cromoglycate on compound 48/80-induced histamine release were studied. We conclude that superfusion is a valid alternative to study mediator release from isolated peritoneal cells.     

Corneal epithelial barrier function after oxybuprocaine provocation in diabetics

Corneal epithelial permeability for fluorescein was determined after provocation by a local anesthetic in 18 non-insulin-dependent diabetes mellitus (NIDDM) patients, 23 insulin-dependent diabetes mellitus (IDDM) patients, and 22 healthy controls to evaluate the corneal epithelial barrier function in diabetes. All volunteers had Oxybuprocaine instilled into one eye and saline into the other eye. The epithelial permeability values were determined by fluorophotometry, and the ratio between both eyes was calculated for each individual. The mean permeability values of the saline-instilled eyes in the diabetic patients did not differ significantly from those in the healthy controls (P greater than 0.2). The individual ratios between Oxybuprocaine- and saline-instilled eyes in the NIDDM and IDDM patients differed significantly from those in the healthy controls (mean ratios: 2.6, 1.9, and 1.0, respectively; P less than 0.002). The permeability ratios and the percentage glycosylated hemoglobin (HbAlc) were linearly correlated in the NIDDM patients but not in the IDDM patients (r = 0.73, P less than 0.001, and r = 0.09, P greater than 0.68, respectively). The results showed that the corneal epithelial barrier function in the diabetic patients was not impaired compared with that in the healthy controls. After provocation by a local anesthetic, the barrier function was impaired in the diabetic patients only.     

Keeping the arm in the limelight: advanced visual control of arm movements in neonates.

To test whether newborn babies have voluntary control over their limbs, spontaneous arm-waving movements were measured in the dark while the baby lay supine with its head turned to one side. A narrow beam of light was shone over the baby's nose or chest in such a way that the arm the baby was facing was only visible when the hand encountered the, otherwise, invisible beam of light. The results showed the babies were capable of precisely controlling the position, velocity, and deceleration of their arms so as to keep the hand visible in the light. The findings indicate that newborns can purposely control their arm movements to meet external demands and that the development of visual control of arm movement is underway soon after birth.     

Tape stripping of human stratum corneum yields cell layers that originate from various depths because of furrows in the skin

Received: 21 November 1996     

Oral administration of methylergometrine shows a late and unpredictable effect on the non-pregnant human menstruating uterus

Objective: To study the pharmacodynamic and pharmacokinetic properties of oral and intravenous methylergometrine upon uterine motility during menstruation. Study-design: Intra-uterine pressure was measured in six volunteers with a fluid-filled sponge-tipped catheter during menstruation. Methylergometrine was given orally (0.5 mg) or intravenously (0.2 mg) in a cross-over design. Results: After intravenous administration, a fast increase of the frequency of uterine contractions and basal tone occurred with a decrease of amplitude, lasting at least 30 min. Oral administration had a late and less marked effect on uterine motility. An intravenous dose administered 24 h after an oral dose had no effect on uterine motility. Pharmacokinetic data, such as the maximum plasma concentration (C_max), the time at which C_max is reached (t_max) and the half-life of absorption (t_1/2abs) also demonstrated large individual variations after oral administration. Conclusion: Oral administration of methylergometrine had an unpredictable and late effect on uterine motility on the menstruating uterus, probably due to an unpredictable bioavailability, in contrast with the fast and predictable effect after intravenous administration.     

Regulation of CD59 expression on K562 cells: effects of phorbol myristate acetate, cross-linking antibody and non-lethal complement attack.

CD59 is the major membrane attack complex of complement (MAC) inhibiting protein on human cells. Its regulation is therefore an important factor in determining the fate of cells at sites of complement activation. We have chosen the K562 erythroleukaemia cell line as a model for studies of the regulation of CD59 expression, because it has previously been reported that phorbol 12-myristate 13-acetate (PMA) caused a 15-fold up-regulation of CD59 mRNA in these cells, implying a substantial capacity for CD59 synthesis. However, no assessment of CD59 protein expression was made in these studies. We show here that surface expression of CD59, as assessed by flow cytometry, was increased four-fold over a 16-hr incubation with PMA, whereas surface expression of decay-accelerating factor (DAF) (CD55) and membrane cofactor protein (MCP) (CD46) was not altered. The newly expressed CD59 was functionally active and anchored through glycosyl-phosphatidylinositol (GPI). Increased expression was dependent upon de novo protein synthesis. CD59 released into cell supernatant was also increased seven-fold by PMA, this 'secreted' CD59 retained its GPI anchor. Non-lethal complement attack did not alter CD59 expression but antibody cross-linking of CD59 caused a rapid loss of the CD59-antibody complexes. However, CD59 was quickly restored to pre-attack levels. This rapid restoration was not dependent upon protein synthesis, suggesting release from preformed stores.