Regional cerebral tissue oxygen saturation changes following blood transfusion in neuro-intensive care unit patients - a pilot observational study.

BACKGROUND: Although central venous oxygen saturation (ScvO2 ) is used to decide on red blood cell (RBC) transfusion, whether its improvement is associated with parallel improvement in cerebral oxygenation is not adequately studied. This study looked at changes in regional cerebral tissue oxygen saturation (rSO2 ) following RBC transfusion in neuro-intensive care unit (ICU) patients. METHODS: In this prospective observational pilot study, rSO2 was measured in adult neuro-ICU patients before RBC transfusion, at the end and at 6, 12, 18 and 24 h after RBC transfusion. rSO2 measurements were taken using cerebral oximetry on both sides of the hemicraniums. Haemoglobin, central venous pressure, ScvO2 and temperature were recorded during the study period. Arterial oxygen content, central venous oxygen content and cerebral fractional oxygen extraction were calculated. Mann Whitney U test was used to study the changes in variables at baseline and at 24 h following RBC transfusion. Friedman's test was used to study changes in parameters from baseline to 24 h post-transfusion. A P value of <0·05 was considered to be significant. RESULTS: The data from 13 subjects were analysed. rSO2 increased significantly following RBC transfusion on both sides of the brain (P = 0·002, P = 0·007), with a corresponding decrease in cerebral fractional oxygen extraction (P = 0·001, P = 0·007). CONCLUSIONS: RBC transfusion increased rSO2 significantly on both sides of the brain. As patients' outcomes were not studied, whether this increase in regional cerebral oxygen saturation is beneficial or if it is because of excess DO2 is still unclear. Further studies are required to clarify this issue.

Effect of treatment with 4-hydroxyandrostenedione on the peripheral conversion of androstenedione to estrone and in vitro tumor aromatase activity in postmenopausal women with breast cancer.

The effect of treatment with the aromatase inhibitor, 4-hydroxyandrostenedione (4-OHA) on the peripheral conversion of androstenedione to estrone has been examined in eight postmenopausal women with advanced breast cancer. Before treatment conversion of androstenedione to estrone ([p]AEIBB) ranged from 0.81 to 3.7% and was almost completely inhibited after treatment with 4-OHA (two doses of 500 mg i.m. with an interval of 12 days between doses). Transfer constants were also measured by the urinary method ([p]AEIBU) for some subjects and decreased from 2.3 +/- 0.52% to 0.24 +/- 0.11% after treatment, a mean reduction of 90%. Mean plasma concentration of estradiol (37.4 +/- 16.6 pmol/liter) and estrone (99.0 +/- 32.2 pmol/liter) decreased significantly (P less than 0.01) to 15.7 +/- 4.6 pmol/liter and 52.4 +/- 8.9 pmol/liter, respectively, after treatment. Aromatase and DNA polymerase alpha (a marker of cell proliferation) activities were measured in seven samples of breast tumor tissue obtained before and after treatment. For three samples there was a marked (67 +/- 17%) decrease in tumor aromatase activity after treatment, for two, little change occurred, while tumor aromatase activity in the other two samples appeared to be resistant to the effect of 4-OHA. The correlation between tumor aromatase and DNA polymerase alpha activities (r = 0.45) failed to reach a significant level.

Epidermal growth factor and oestradiol in human breast cyst fluid.

Gross cystic breast disease is a common condition in women. Women with apocrine breast cysts (breast cyst fluid Na+/K+ less than 3) may be at higher risk of breast cancer than women who have cysts lined by flattened epithelium (Na+/K+ greater than or equal to 3). Breast cyst fluid concentrations of epidermal growth factor were significantly higher in the low electrolyte ratio group than in the high electrolyte ratio group (356.2 ng/ml vs 104.1 ng/ml, P less than 0.0003). A negative correlation was obtained between intracystic epidermal growth factor concentrations and Na+/K+ (rs = -0.666, P less than 0.001). No significant difference was found between the total oestradiol concentrations in the two cyst groups. However, the unbound oestradiol concentrations on a limited number of samples were significantly higher in the low electrolyte ratio group than in the high electrolyte ratio group (P less than 0.05). The higher concentrations of EGF in cyst fluid with Na+K+ less than 3 may explain why women with apocrine breast cysts may be at increased risk of developing breast cancer.

Lipid absorption and metabolism.

Metabolic processes occurring within the mucosal cell are critical in determining results of interactions between environmental agents and the alimentary tract. The absorption, metabolism, and transport of lipids affects most those agents which are lipid soluble. The understanding of the process involved in lipid absorption and transport is therefore important for both appreciation of the mechanism of uptake of these toxins and for an effective interference with it. Most of the detailed mechanisms of lipid absorption and transport have been proposed from in vitro studies with soluble cell-free systems. The present review integrates these results with recent in vivo and in vitro findings with intact animal tissues and isolated mucosal cells. While there is much general agreement occasional startling differences are also observed, which may have a bearing on the mechanism of normal fat absorption and on the understanding of the transport of the fat-soluble toxins across the mucosal villus cell.

Postirradiation angiosarcoma of the breast--a case report.

Angiosarcoma of the breast is an uncommon neoplasm but coincident angiosarcoma with infiltrating ductal carcinoma is not yet reported. This paper describes a case of angiosarcoma which developed after 4 years of a wide excision and adjuvant radiotherapy for a ductal carcinoma of the breast. Due to latent period of only 4 years radiotherapy cannot be blamed as an aetiological factor in this case but neither is it possible to exclude it as a causative factor.

Antiarrhythmic potential of chloroquine: new use for an old drug.

Amiodarone and chlorpromazine are phospholipase inhibitors which produce cytoplasmic inclusion bodies and have important electrophysiologic properties. Chloroquine also inhibits phospholipase activity, resulting in similar inclusion bodies, but electrophysiologic information about this drug is lacking. In this study, the cellular electrophysiologic effects of two doses of chloroquine were examined in sheep Purkinje fibres and ventricular muscle cells. Both concentrations produced a significant reduction in maximum velocity of upstroke of the action potential and prolongation of the action potential duration and refractory period in Purkinje fibres. These effects were observed in the absence of significant changes in threshold of stimulation or action potential amplitude and were partially reversible following washout of the lower drug concentration. In addition to these experimental data, clinical evidence of antiarrhythmic action was determined by administering 500 mg chloroquine daily over nine weeks to six subjects with frequent asymptomatic ventricular premature complexes. In four patients there was a reduction in ventricular ectopy, which recurred when the drug was discontinued, while a fifth patient reverted to sinus rhythm from atrial fibrillation previously resistant to other antiarrhythmic medication. Thus, chloroquine has important electrophysiologic properties. The underlying mechanism of this action remains unproven at the present time.

Comparative study of repair of incisional hernia.

Repair of incisional hernias was compared with four different techniques in 55 patients to determine the best method of repair with least chance of recurrence. The maximum incidence of incisional hernia was seen in 30-39 years age group and was most frequently seen after gynaecological surgery (37 cases). Forty eight (88%) patients were operated in emergency by trainee surgeons. Most hernias occurred within one year after surgery and the herniation of lower mid line incision was more frequent (70.9% cases). History of wound infection of previous surgery was recorded in 45.5% of cases which appeared to be the important risk factor in causation of incisional hernia. It was also observed that simple repair of incisional hernia was associated with a high recurrence than that where synthetic mesh was used in repair where no recurrence was recorded.

Characterization and analysis of the subclasses and molecular species of choline phosphoglycerides from porcine heart by successive chemical hydrolyses and reverse phase high-performance liquid chromatography.

Choline phosphoglycerides (CPG) represent the major fraction of heart phospholipids. Since depletion of membrane phospholipids and accumulation of lyso-compounds, particularly lysophosphatidylcholines, have been implicated in arrhythmogenesis, it was of great interest to study the composition of this major phospholipid fraction of the heart at a molecular level in an established animal model. The data presented here describe the first report on the detailed chemical examination of CPG and resolution, characterization and quantitative analysis of the molecular species of this phospholipid fraction from porcine heart by high performance liquid chromatography (HPLC). This fraction constitutes 37.5 +/- 0.7% (n = 21) of the total phospholipids and upon successive mild acid and alkaline hydrolyses revealed the presence of essentially three subclasses: diacyl-, alkenylacyl-, and alkylacyl glycerophosphorylcholines, in a relative abundance of 57.7 +/- 2.2% (n = 8), 37.3 +/- 1.3% (n = 8) and 4.6 +/- 0.2% (n = 8), respectively. The fourth subclass, dialkyl CPG was found only in minute amounts (0.43 +/- 0.05%, n = 8) and the presence of dialkenyl and alkenylalkyl analogues could not be detected. Alternatively, by converting the CPG fraction to benzoate derivatives after phospholipase C digestion, it was possible to isolate and quantitate subclass composition by TLC/spectroscopy or both subclass compositions and molecular species analysis by HPLC directly by a UV detector online with the column. By these techniques, subclass composition was found to be very similar to that obtained by the chemical hydrolysis technique. By HPLC, up to 25 species can be identified and quantitated in each subclass, their identity being confirmed by gas-liquid chromatography, after their isolation from the column. The analyses showed that up to 74% of the diacyl moiety consisted of 16:0-18:2 (34%), 16:0-18:1 (27%), and 18:0-18:2 (13%) species, while the major species of the alkenylacyl moiety were 16:0-18:2 (44%) 16:0-18:1 (13%), 16:0-20:4 (12%) and 18:1-18:2 (9%) making up more than 75% of the total mass of this subclass. The major molecular species of the alkylacyl moiety was 16:0-18:2, constituting up to 47% of this fraction, while others constituted about 10% (16:0-18:1), 9% (18:1-18:2), 8% (16:0-20:4) and 6% (18:0-18:2), making up 80% of the total mass. The ether chain composition of akylacyl CPG whether determined after isolation of this fraction by the chemical hydrolysis technique or by HPLC was indistinguishable.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of amiodarone therapy on the time course of myocardial phospholipid hydrolysis during in vitro total ischaemia in cat hearts.

The effects of chronic amiodarone therapy on myocardial phospholipid hydrolysis induced by total in vitro ischaemia were investigated in cat hearts. Chronic treatment of cats with amiodarone (30 mg/kg/day, orally) for 6 weeks resulted in a sufficient uptake of the drug reaching tissue levels of 83 +/- 13 & 122 +/- 22 microM (n = 12) for amiodarone and its principle metabolite, desethylamiodarone, respectively. This was accompanied by a significant increase (37%, P less than 0.001) in total phospholipid content of heart in treated as compared to untreated animals. Upon in vitro total ischaemia, these endogenous drug levels were sufficient to attenuate significantly hydrolysis of membrane phospholipid. The degree of attenuation was dependent upon the duration of ischaemic insult. In this regard, protection against phospholipid losses by amiodarone treatment was significantly more in the later irreversible phase of ischaemic injury whether studied in an in vitro total ischaemia model or in an isolated perfused heart preparation. Similar trend was observed in the relative accumulation of lysophospholipid and non-esterified fatty acid levels during ischaemia, i.e. both were significantly attenuated by amiodarone treatment. However, in contrast to the fatty acid data, the net changes in lysophospholipids per gram tissue wet weight were similar in treated and untreated animals, suggesting that the protective effects of amiodarone may have involved other enzymes including phospholipase C and D. Also, during the entire time course studied, all the phospholipid classes appeared to be affected to more or less a similar degree, indicating that the effects of the drug may have manifested in other subcellular compartments besides lysosomes. However, at all time periods studied, the net release of eicosatetraenoic and docosahexaenoic acid (fatty acids occupying primarily sn-2 position of phospholipids) was different, release of the former fatty acid being inhibited more than the latter, suggesting specific interaction of amiodarone with the molecular species of phospholipid. The data suggest that amiodarone attenuates ischaemia-induced membrane lipid abnormalities in part through modulation of phospholipid metabolism, and that this effect may be one of the key determinants which contribute to its antiarrhythmic properties during acute ischaemia.

Assessment of various techniques for the quantitative extraction of lysophospholipids from myocardial tissues.

Lipid extraction methods were evaluated for their effectiveness in extracting lysophosphatidylcholines and lysophosphatidylethanolamines from tissues and for subsequent recoveries during purification of crude extracts. The acid-butanol technique, although effective in complete extraction, resulted in partial hydrolysis (2-10%) of phospholipids containing 1-alk-1'-enyl-2-acylglycerophospholipids (plasmalogens) to produce artifactual lysophospholipids. This problem was avoided using a neutral butanol extraction or Bligh and Dyer techniques, but these resulted in only partial recoveries (60-72 and 75-80%, respectively) of these lipids. Tissue extracted with neutral chloroform-methanol mixtures provided virtually complete extraction (97-100%), but subsequent losses (up to 15%) occurred during purification of crude extracts with Folch synthetic upper phases. These losses could be circumvented by purification of the crude extract on Sephadex G-25 column. As an alternative, the Folch extraction technique was modified to achieve complete recoveries of lysophospholipids. This involved extraction of the tissue with a chloroform-methanol-saline biphasic system. After removal of the lower lipid phase, the upper phase containing residual tissue was reextracted twice more with Folch lower phase and once with lower phase containing HCl. This last extract was neutralized with NH3 vapor before pooling with the preceding extracts. This method (i) circumvents plasmalogenic hydrolysis, (ii) avoids use of time-consuming column chromatography, (iii) eliminates the losses of lipids during purification, and (iv) allows highly reproducible quantitative analyses of all lipid fractions including lysophospholipids and nonesterified fatty acids from myocardial tissue.

Effects of chronic amiodarone treatment on cat myocardial phospholipid content and on in vitro phospholipid catabolism.

Amiodarone is used extensively for the chronic treatment of life-threatening arrhythmias caused by ischemic heart disease. However, chronic therapy with this agent results in phospholipidosis in various tissues and it has been suggested that the inhibition of lysosomal phospholipase A by this drug contributes to this abnormality. Exogenous amiodarone has been shown to inhibit purified rat liver lysosomal phospholipase A1, as well as acid phospholipase activities of alveolar macrophage homogenates and those of snake venom phospholipase A2 and bacterial phospholipase C. The effects of drug treatment on heart have not been explored. The results described here demonstrate that amiodarone also significantly increases (37%, p less than 0.001) phospholipid content in cat hearts. This increase is proportionately distributed to all major phospholipid classes, with the exception of sphingomyelin which appears to increase more than the others. In addition, the data also show that following amiodarone treatment, the endogenous drug levels in the heart were sufficient to reduce in vitro losses of membrane phospholipid at 37 degrees C by inhibiting a variety of endogenous phospholipases at physiological (7.4), ischemic (6.2) and acidic (5.0) pH values. This protection is more pronounced at acidic pH values than at physiological pH. Endogenous amiodarone also affects myocardial phospholipase activities towards exogenous phosphatidylcholine and again the extent of inhibition is more at acidic pH. These results suggest that amiodarone induces phospholipidosis in the heart by inhibiting phospholipid catabolism and that its antiarrhythmic properties may reside in its ability to modulate alkaline, neutral and acid phospholipase activities in ischemia. To what extent amiodarone metabolites (desethylamiodarone and bis-desethylamiodarone) are involved in these actions remains to be determined.

Time course of changes in porcine myocardial phospholipid levels during ischemia. A reassessment of the lysolipid hypothesis.

This study was performed to determine the early and delayed metabolic effects of myocardial ischemia on the major membrane phospholipids and to reassess the potential role of lysophospholipids in the genesis of malignant dysrhythmias induced by ischemia. Samples taken from in situ hearts before ant at various intervals up to 40 minutes after abrupt ligation of LAD were extracted by the classical Folch technique with modifications to avoid artifactual lysophospholipid production and losses. Following thin layer chromatography of lipid extracts, phospholipid fractions were quantified by phosphorus estimation and lysophospholipids by a more sensitive method employing gas liquid chromatography. The total phospholipid content with the exception of lysophospholipids remained essentially constant throughout the early phases of acute ischemia, but fell by 6 and 14% after 8 and 24 ours, respectively. At 8 minutes, lysophospholipid levels n ischemic myocardium were significantly increased by 60% compared to pre-occlusion controls in the ischemic zone and by 25% in post-occlusion controls. They changed little thereafter. The molecular species of lysophospholipids remained unchanged throughout the period of ischemia studied. The mole fraction of other phospholipids as well as their fatty acyl and aldehyde profiles also were unchanged. Despite significant elevations in lysophospholipids levels, their absolute quantities were very small (0.6% of total phospholipid P) and 15-fold smaller than that reported in vitro to simulate electrophysiological manifestation of ischemia. However, such small amounts in vivo, if produced in the microenvironment of certain membrane-bound enzymes along with acidosis, hypoxia, and fatty acids, could be potentially deleterious to cell functions.

Expansion of phospholipid pool size of rat intestinal villus cells during fat absorption.

The effect of fat absorption upon the phospholipid pool size of the intestinal mucosal cells was determined in rats receiving fatty emulsions as a bolus by stomach tube or as multiple meals in the form of fat-laden laboratory chow. The phospholipid content of the mucosal scrapings and of the isolated villus cells was determined 3 to 34 h after the meals and was compared with the phospholipid content of cells from similar animals receiving water alone or 10% sucrose in water. It was shown that continuously fed animals averaged 5-10% and single meal fed animals up to 40% higher phospholipid content in their mucosal cells than the corresponding controls, when compared per milligram cell protein. The expansion of the phospholipid pool involved all phospholipid classes and correlated well with the phospholipid composition of prechylomicrons and of microsomal membranes, which undergo a significant proliferation during fat absorption. The apparent lower expansion of the phospholipid pool in the continuously fed animals correlated with the lower triacylglycerol content of the lumen and of the cells at these times.

Further evidence for enhanced phospholipid synthesis by rat jejunal villus cells during fat absorption.

The effect of fat absorption on the phospholipid turnover of rat intestinal mucosa was determined in animals receiving single fatty meals by stomach tube or multiple meals in the form of corn-oil-soaked laboratory chow diet. The specific activity and relative specific activity of the total phospholipids and of individual phospholipid classes were measured in the isolated jejunal villus cells of fasting and fat-fed animals following an injection of radioactive inorganic phosphate 0.5-31 h prior to sacrifice, which was scheduled to coincide with the peak of fat absorption (2.5-3 h after the last meal). It was shown that the relative specific activity of the fat-absorbing cells increased by about 33% when the samples were taken 0.5 h after intravenous injection of radioactive phosphate. Samples taken 11 and 31 h after the introduction of the radioactive phosphate showed about 16% decrease in the relative specific activity of the phospholipids of the fat-absorbing cells when compared with the fasting controls. These changes in the relative specific activity of the total phospholipids included all phospholipid classes and corresponded to the recently described expansion of the cellular phospholipid pool owing partly to increased de novo synthesis of the membrane phospholipids. The present results are consistent with the known biochemical and physiological changes taking place in the mucosal cells during fat absorption and transport and find support in various less direct biochemical and morphometric measurements.

The incidence of post-vasectomy chronic testicular pain and the role of nerve stripping (denervation) of the spermatic cord in its management.

OBJECTIVE: To assess the incidence of chronic postvasectomy testicular pain (CPTP) and evaluate the use of denervation of the spermatic cord in its management. PATIENTS AND METHODS: A retrospective postal survey of 560 patients (mean age 36 years, range 25-55; mean time since vasectomy 19 months, range 8-39) who underwent vasectomy between July 1992 and December 1994 was carried out to determine the incidence of CPTP. A prospective study was conducted in a further group of 17 patients (mean age 43 years, range 34-60), who had had CPTP for at least one year, to evaluate the effectiveness of nerve stripping of the spermatic cord in relieving pain. RESULTS: Of 396 replies, 108 (27.2%) patients complained of some testicular pain following their vasectomy operation. In 88 (82%) of these 108 patients the pain was brief and was not defined as CPTP, while 20 (19%) patients had pain for > 3 months; 33 (31%) patients required analgesics to control the pain. Of the 17 patients who underwent spermatic cord denervation, 13 reported complete relief of pain at their first follow-up visit and were discharged. Four patients had a significant improvement in the symptom score and were satisfied with the results. CONCLUSIONS: There is a small but significant incidence of CPTP and patients should be warned of this possibility when counselled before operation. Denervation of the spermatic cord seems to be a viable surgical option for patients with CPTP who fail to respond to conservative measures.

Ultrastructural changes of ischemic injury due to coronary artery occlusion in the porcine heart.

Using the ultrastructural criteria established by Schaper et al. 1979 [27] for distinguishing between different degrees of ischemic change in dog myocardium, slight ischemic changes are observed in the pig suboendocardium as early as 1 min after occlusion of the LAD artery. Moderate change throughout the thickness of the myocardium is seen after 6 to 12 min of ischemia and continues to be found up until 20 min after commencement of the ischemic period. 20 to 30 min ischemia produces severe ischemic damage and more than 30 min leads to irreversible damage. The changes are uniform at all stages of ischemia and there is no evidence of a transmural gradient of ultrastructural damage. Of particular interest in the early part of the ischemic period is the observation of ultrastructural changes in the subendocardial specialized conducting tissue. In these specialized cells, although morphological features consistent with slight and moderate ischemia are found as early as 1 to 2 min after occlusion, spontaneous recovery occurs and is complete by 15 min. This biphasic time course parallels the electro-physiological changes known to occur in ischemic Purkinje fibres.

Amiodarone--an inhibitor of phospholipase activity: a comparative study of the inhibitory effects of amiodarone, chloroquine and chlorpromazine.

Amiodarone, an antiarrhythmic drug, like chloroquine and chlorpromazine, is a tertiary amine with amphiphilic properties. Chloroquine and chlorpromazine are known inhibitors of phospholipases. All three drugs produce characteristic microcorneal deposits consistent with lysosomal accumulations of phospholipid. Similar lysosomal bodies were found in leukocytes of 15 patients on chronic amiodarone treatment as well as 3 patients each on chloroquine and chlorpromazine, suggestive of widespread systemic inhibition of lysosomal phospholipases. These lysosomal inclusions were similar in morphology, irrespective of the drug given, and were of four types: multilamellar, amorphous dense, amorphous light, or a combination of 2 or more of the preceding types. There was no simple relationship between the number of inclusion bodies per cell and the cumulative dose of amiodarone (r = 0.02) or amiodarone serum levels (r = 0.11). An in vitro assay was used to compare the effects of the three drugs on Ca2+-dependent phospholipase A2 and C activities. Phospholipase A2 activity was inhibited in a dose-dependent fashion (1-8 mg/assay) by all three drugs in the order: chlorpromazine greater than amiodarone greater than chloroquine. The inhibitory effect on phospholipase C was more pronounced with all three drugs, producing almost total inhibition at 8 mg/assay. In a Ca2+-independent lysosomal phospholipase A system, amiodarone had a greater effect, producing 85% inhibition at 1.2 mg/assay. These observations suggest that amiodarone, like other cationic amphiphiles, induces a generalized phospholipidosis by inhibiting phospholipid catabolism. Its therapeutic and toxic effects may be due to its ability to modulate both Ca2+-dependent membrane phospholipases and Ca2+-independent acid phospholipases.