The effect of triacylglycerol fatty acid positional distribution on postprandial plasma metabolite and hormone responses in normal adult men

The present study has examined the possibility that the positional distribution of fatty acids on dietary triacyglycerol (TAG) influences the postprandial response to a liquid meal in adult subjects. Postprandial TAG, non-esterified fatty acids (NEFA), ketones, glucose, insulin and gastric inhibitory polypeptide (GIP) responses were monitored in sixteen normal adult male subjects over 6 h following consumption of test meals containing dietary TAG in which palmitic acid was predominantly on the sn-1 (Control) or sn-2 positions (Betapol). Plasma total TAG, chylomicron-rich TAG and chylomicron-poor TAG concentrations were identical in response to the two test meals. The peak increase (mean (SD)) in chylomicron TAG was 0.85 (0.46) mmol/l after the Control meal and 0.85 (0.42) mmol/l after the Betapol meal. Plasma glucose, insulin, GIP, NEFA and ketone concentrations were also very similar following the two meals. It is concluded that dietary TAG containing saturated fatty acids on the sn-2 position appear in plasma at a similar level and over a similar timescale to TAG in which saturated fatty acids are predominantly located on sn-1 or sn-3 positions. The results reported in the present study demonstrate that the positional distribution of fatty acids on dietary TAG is not an important determinant of postprandial lipaemia in adult male subjects, but do not exclude the possibility that different responses may occur when these dietary TAG are given long term.

The safety and pharmacokinetics in adult subjects of an intravenously administered 99mTc-labeled 17 amino acid peptide (CYT-379)

A phase I study was designed to evaluate the safety and pharmacokinetics of a novel platelet reactive peptide, peptide acetyl-SYGRGDVRGDFKCTCCA-amide (CYT-379), which binds to the fibrinogen receptor of activated platelets and also binds to 99mTc. Eleven subjects with suspected deep venous thrombosis had 0.1, 0.5 or 1.0 mg of the peptide infused intravenously. Pharmacokinetics were determined by assaying blood samples in 6 of the 11 subjects and by urine sampling in 5 of these 6 subjects. Plasma and whole blood time-activity curves demonstrated an initial fast component with half-time clearance of 0.2 +/- 0.01 and 0.2 +/- 0.02 h and a slow component with half-time clearance of 2.8 +/- 0.3 and 2.7 +/- 0.2 h (mean +/- SEM for plasma and whole blood, respectively). Urine clearance was 22.6 +/- 3.3 and 10.8 +/- 1.6 mL/min when normalized to body surface area. The cumulative excretion of 99mTc-CYT-379 in the urine was 16.6 +/- 3.6, 45.6 +/- 16.9 and 45.6 +/- 1.8% of the administered dose over 0-2, 0-12 and 0-24 h after radiopharmaceutical injection, respectively. Images obtained in 11 subjects immediately, at 1-2, and 4-6 h after injection were evaluated for abnormalities and were compared with duplex Doppler ultrasonography. 99mTc-CYT-379 images were positive in only 3 of 7 subjects who had a positive duplex Doppler examination in at least one lower extremity. One subject with negative duplex Doppler had also negative 99mTc-CYT-379 scintigraphy. One subject with negative scintigraphy and two other subjects with positive scintigraphy had no other imaging studies of the deep venous system performed. No adverse reactions were observed during or after the infusion of 99mTc-CYT-379. 99mTc-CYT-379 appears to be a safe radiopharmaceutical and demonstrates rapid clearance from plasma in human subjects.

Pretranslational regulation of the expression of the lipoprotein lipase (EC 3.1.1.34) gene by dietary fatty acids in the rat

Although there have been a number of studies of effects of diet and hormones on lipoprotein lipase (EC 3.1.1.34; LPL) activity and levels of LPL mRNA (Raynolds et al. 1990), there have been no studies which have investigated effects of different dietary fatty acids on LPL gene expression. In the present study male Wistar Albino rats were pair-fed diets containing 50 g fat/kg of different fatty acid composition for 2 weeks. The diets fed were (1) a mixed oil (450 g saturated fatty acids, 420 g monounsaturated fatty acids, 130 g polyunsaturated fatty acids/kg; n 8), (2) maize oil (n 8), or (3) fish oil (n 8). Animals were killed, RNA was extracted from liver and perirenal and epididymal fat pads, and analysed by 'Northern methodology'. Samples were hybridized to a human cDNA probe for LPL (Gotoda et al. 1989). Two transcripts were identified in epididymal and perirenal adipose tissue which were approximately 3.7 and 1.7 kb in size. The results suggested that (1) fish oil-fed animals had significantly greater production of LPL mRNA in epididymal adipose tissue compared with maize oil-fed animals (P < 0.05), (2) maize oil-fed animals had significantly greater production of LPL mRNA in perirenal fat compared with the other dietary groups (P < 0.05), (3) expression in the liver was not significant. Rats fed on a fish oil diet had significantly reduced plasma triacylglycerol concentrations compared with the mixed-oil group (P < 0.05), but there were no significant differences in plasma cholesterol. The differences in LPL could not be explained directly by the changes in plasma immunoreactive-insulin and glucose-dependent insulinotrophic polypeptide levels in the three groups.

A novel antiserum specific to apolipoprotein B-48: application in the investigation of postprandial lipidaemia in humans

1. Apolipoprotein B-48, the transport protein for chylomicrons, is identical with apolipoprotein B-100 for the first 48% of its sequence. No antiserum has yet been reported that can recognize apolipoprotein B-48, but not apolipoprotein B-100. 2. In the present study an antiserum was raised to the C-terminal sequence of apolipoprotein B-48, using specific chemical reactions to ensure that the charged carboxyl group of the C-terminal isoleucine residue was free. In a Western blot the antiserum was shown to bind to a protein band having the characteristics of apolipoprotein B-48, but not to apolipoprotein B-100. 3. In the early evening 11 subjects were given a test meal which contained 40 g of mixed oil and retinyl palmitate. Blood samples were collected over 9 h. Chylomicron-enriched fractions were prepared and analysed for triacylglycerol, retinyl palmitate and apolipoprotein B-48, the latter after separation using SDS/PAGE and visualization by chemiluminescence on a Western blot. Both triacylglycerol and apolipoprotein B-48 showed an early peak at 1 h, which was not seen with retinyl palmitate. All three substances gave a broader peak between 5 and 6 h postprandially. Retinyl palmitate concentrations declined rapidly during the late (6-9 h) postprandial period, but apolipoprotein B-48 concentrations remained elevated. 4. This study has shown that an antiserum has been produced which is specific for apolipoprotein B-48. This has enabled measurement of postprandial concentrations of the protein that revealed features of chylomicron metabolism which have not been reported previously.

The use of salicylate hydroxylation to detect hydroxyl radical generation in ischemic and traumatic brain injury. Reversal by tirilazad mesylate (U-74006F)

Oxygen free radicals have been implicated as a causal factor in posttraumatic neuronal cell loss following cerebral ischemia and head injury. The conversion of salicylate to dihydroxybenzoic acid (DHBA) in vivo was employed to study the formation of hydroxyl radical (.OH) following central nervous system (CNS) injury. Bilateral carotid occlusion (BCO) in gerbils and concussive head trauma in mice were selected as models of brain injury. The lipid peroxidation inhibitor, tirilazad mesylate (U-74006F), was tested for its ability to attenuate hydroxyl radical formation in these models. In addition, U-74006F was studied as a scavenger of hydroxyl radical in an in vitro assay based on the Fenton reaction. For in vivo experimentation, hydroxyl radical formation was expressed as the ratio of DHBA to salicylate (DHBA/SAL) measured in brain. In the BCO model, hydroxyl radical formation increased in whole brain with 10 min of occlusion followed by 1 min of reperfusion. DHBA/SAL was also found to increase in the mouse head injury model at 1 h postinjury. In both models, U-74006F (1 or 10 mg/kg) blocked the increase in DHBA/SAL following injury. In vitro, reaction of U-74006F with hydroxyl radical gave a product with a mol wt that was 16 greater than U-74006F, indicative of hydroxyl radical scavenging. We speculate that U-74006F may function by blocking oxyradical-dependent cell damage, and thereby maintaining free iron (which catalyzes hydroxyl radical formation) concentrations at normal levels.

Fatty acid compositions of inositol and choline phospholipids of breast tumours and normal breast tissue

The fatty acid compositions of the -choline and -inositol phospholipids of breast tumours of women undergoing surgery for treatment of breast disease (malignant n = 12; benign n = 10) and normal breast tissue of women undergoing breast reduction surgery (n = 6) were determined. The fatty acid compositions of erythrocyte phospholipids were also determined in the same subjects and in an additional number of normal healthy volunteers (n = 16). Levels of oleic acid were lower in both phospholipid fractions of erythrocytes of women with breast disease and in the phosphatidylcholine fraction of breast tumours compared with normal breast tissue. Significantly higher levels of linoleic acid were found in erythrocytes of tumour-bearing subjects and a similar trend was evident in the phosphatidylcholine fraction of tumour compared with normal breast tissues. Conversely, lower levels of two of the products of linoleic acid chain elongation and desaturation, dihomogamma-linolenic and arachidonic acids, were found in the erythrocyte phospholipids of tumour-bearing subjects and in the choline phospholipids of breast tumour tissues. These data suggest that in women with breast disease, there may be inhibition of 6-desaturase, and enhanced activity of 9-desaturase, enzymes which play an important role in determining membrane phospholipid fatty acid composition. This pattern of altered fatty acid composition characteristic of erythrocyte phospholipids of tumour-bearing subjects and phosphatidylcholine of breast tumour tissue was less evident in the case of the breast tumour phosphatidylinositol in which differences other than those described were seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of n-3 fatty acids on postprandial triacylglycerol and hormone concentrations in normal subjects

The present study reports results from two investigations to determine effects of a 6-week period of moderate n-3 fatty acid supplementation (2.7 g/d) on fasting and on postprandial triacylglycerol and metabolic hormone concentrations in response to standard test meals. In the first study postprandial responses were followed for 210 min after an early morning test meal challenge; in the second study responses to an evening test meal were followed during the evening and overnight for a total period of 12 h. In both studies postprandial triacylglycerol responses to the test meals were significantly reduced after compared with before fish-oil supplementation. In the second study the triacylglycerol peak response seen between 200 and 400 min in subjects studied before supplementation with fish oils was almost completely absent in the same subjects after 6 weeks of n-3 fatty acid supplementation. Analysis of fasting concentrations of metabolites and hormones was carried out on the combined data from the two studies. There were no significant differences in total, low-density-lipoprotein- or high-density-lipoprotein-cholesterol concentrations during fish-oil supplementation, although there was considerable individual variation in cholesterol responses to the supplement. Concentrations of Apo-B and Apo-A1 were unchanged during supplementation with fish oils. Fasting and early morning postprandial GIP concentrations were lower in subjects taking fish oils, possibly due to acute effects of fish-oil capsules taken on the evening before the studies. In both studies fasting insulin and glucose and postprandial insulin concentrations remained unchanged following fish-oil supplementation. The results do not support the view that triacylglycerol-lowering effects of n-3 fatty acids are due to modulation of insulin secretion mediated via the enteroinsular axis. Further studies are required to determine the precise mechanism by which fish oils reduce both fasting and postprandial triacylglycerol concentrations.

Method for registering brain SPECT and MR images

We have developed a simple method for locating functional regions of interest on successive SPECT scans obtained at different times and for locating neuroanatomical regions defined with MR on functional images obtained with SPECT. Plastic molds are made for each external auditory meatus and the glabella. A pocket is then made in each mold in which either a 57Co disk (for SPECT) or an identical disk containing CuSO4 solution (for MRI) can be placed. Transaxial tomographic slices are reconstructed with the same slice thickness in the two modalities. The SPECT software rotates both SPECT and MRI reconstructed images so that the three 57Co markers lie in one SPECT reference plane and the three CuSO4 markers lie in one MRI reference plane. Corresponding SPECT and MR images may then be displayed simultaneously to locate chosen regions of interest. The technique was validated by taping test markers to the forehead of 12 subjects; the difference between the positions of the centers of the test markers on SPECT and MR scans was within 1 SPECT acquisition pixel size.

Improvement of Longevity and Viability of Sperm Cells Isolated from Pollen of Zea mays L

Our previous studies showed that the common maize (Zea mays L.) sperm isolation medium (Brewbaker and Kwack salts in 0.44 m sucrose without buffering) caused cell lysis in vitro. In an attempt to remedy this situation, 6 sugars, 10 buffers, 5 pH values, and 3 membrane protective agents were screened to improve longevity and viability of isolated Zea mays sperm cells as estimated by hemacytometry and flow cytometry. Use of 0.55 m galactose in the isolation solution increased sperm yield by 2.5-fold compared with sucrose, and suspension of isolated sperm cells in the galactose solution gave the best longevity among the six sugars. Buffering the galactose solution with 2 mm 2-(N-morpholino)ethanesulfonic acid significantly improved longevity, whereas other buffers had no effect or decreased the longevity and/or viability. Among the five pH values tested (5.0, 6.0, 6.7, 7.0, and 8.0), pH 6.7 appeared to be optimal for maintenance of both longevity and viability. Screening of membrane protectants showed that cysteine caused a rapid decrease in cell viability and increased lysis, whereas dithiothreitol increased the cell numbers but lowered their viability. Addition of 0.1% bovine serum albumin increased cell numbers and viability, and about 70% of the cells remained viable after 72 h of suspension. Cell longevity and viability were also improved in 0.44 m sucrose when the solution was conditioned with 2-(N-morpholino)ethanesulfonic acid and bovine serum albumin. Use of 2-(N-morpholino)ethanesulfonic acid and bovine serum albumin inthe isolation and suspension medium significantly improved the viability and longevity of sperm cells isolated from Zea mays pollen.

Effect of dietary fatty acid composition on inositol-, choline- and ethanolamine-phospholipids of mammary tissue and erythrocytes in the rat

The present study investigated the effect of feeding maize-oil, olive-oil and fish-oil diets, from weaning to adulthood, on rat mammary tissue and erythrocyte phospholipid fatty acid compositions. Effects of diet on the relative proportions of membrane phospholipids in the two tissues were also investigated. Mammary tissue phosphatidylinositol (PI) fatty acids were unaltered by diet, but differences in phosphatidylethanolamine (PE) and, to a lesser extent, phosphatidylcholine (PC) fractions were found between animals fed on different diets from weaning. Differences observed were those expected from the dietary fatty acids fed; n-6 fatty acids were found in greatest amounts in maize-oil-fed rats, n-9 in olive-oil-fed rats, and n-3 in fish-oil-fed rats. In erythrocytes the relative susceptibilities of the individual phospholipids to dietary modification were: PE > PC > PI, but enrichment with n-9 and n-3 fatty acids was not observed in olive-oil- and fish-oil-fed animals and in PC and PE significantly greater amounts of saturated fatty acids were found when animals fed on olive oil or fish oil were compared with maize-oil-fed animals. The polyunsaturated:saturated fatty acid ratios of PE and PC fractions were significantly lower in olive-oil- and fish-oil-fed animals. No differences in the relative proportions of phospholipid classes were found between the three dietary groups. It is suggested that differences in erythrocyte fatty acid composition may reflect dietary-induced changes in membrane cholesterol content and may form part of a homoeostatic response the aim of which is to maintain normal erythrocyte membrane fluidity. The resistance of mammary tissue PI fatty acids to dietary modification suggests that alteration of PI fatty acids is unlikely to underlie effects of dietary fat on mammary tumour incidence rates.

Unrecognized left ventricular dysfunction in an apparently healthy alcohol abuse population

To examine effects of chronic alcohol abuse on left ventricular function, 162 otherwise relatively healthy alcohol abusers, having been admitted to a rehabilitation program, underwent cardiac evaluation including chest X-ray, electrocardiogram, and radionuclide angiography after 2 weeks abstinence. Twenty-nine of the 162 alcoholic subjects (18%) with left ventricular dysfunction were identified. Twenty-two had regional wall motion abnormalities, suggesting a localized process, of whom 12 also had depressed ejection fractions. Seven others had a depressed ejection fraction alone with a more global myopathic process. Only 4 of these 29 patients had any history suggesting prior heart disease. Two of the 29 had Q-waves greater than or equal to 0.4 s and 8 had an abnormal cardiothoracic ratio on chest X-ray. Chronic alcohol abusers appear to be at relatively high risk for left ventricular dysfunction; most of which is unrecognized. Routine screening methods failed to identify 85% of our subjects who later were recognized by radionuclide angiography. Since historical and electrocardiographic abnormalities are often absent in this population, detection of left ventricular dysfunction by other methods such as radionuclide angiography must be used.

Left ventricular regional wall motion assessment by radionuclide ventriculography: a comparison of cine display with Fourier imaging

Radionuclide ventriculography and contrast ventriculography were performed in two comparable projections on 50 patients with suspected coronary artery disease. The efficacy of conventional cine display and Fourier image analysis of the radionuclide ventriculogram was compared using contrast ventriculography as the gold standard. Of seven different combinations of Fourier images, the combination of left anterior oblique amplitude and phase and left posterior oblique amplitude and phase provided the highest sensitivity (87%), specificity (83%), accuracy (86%), and kappa coefficient (0.64). To increase statistical power, segment data were collapsed to global data in which a heart was considered normal if all segments were normal and abnormal if one or more segments were abnormal. Fourier images had higher sensitivity (Fourier 87%, cine 47%); lower specificity (Fourier 83%, cine 92%), higher accuracy (Fourier 86%, cine 58%), and higher kappa coefficient (Fourier 0.64, cine 0.25), and these differences were statistically significant (p less than 0.01).

Characterization of a thromboxane A2/prostaglandin H2 receptor in guinea pig lung membranes using a radioiodinated thromboxane mimetic

Thromboxane A2 (TXA2) and prostaglandin H2 (PGH2) are potent constrictors of airway smooth muscle and may mediate some of the pulmonary effects of leukotrienes. To date, the TXA2/PGH2 receptor in lung has not been well characterized. In this report, we describe the evaluation of the TXA2/PGH2 receptor in guinea pig lung membranes using the new radiolabeled TXA2 mimetic [1S(1 alpha,2 beta(5Z),3 alpha(1E,3S*),4 alpha)]-7-[3-(3-hydroxy-4-(4'- iodophenoxy)-1-butenyl)-7-oxabicyclo-[2.2.1]heptan-2-yl]-5-h eptenoic acid (IBOP). IBOP elicited a dose-dependent contraction of guinea pig lung parenchymal strips (EC50 = 3.03 +/- 0.97 nM, three experiments), which was blocked by the TXA2/PGH2 antagonists SQ29548 (pKB = 7.44 +/- 0.2, three experiments), BM13505 (pKB = 6.29 +/- 0.26, three experiments), and I-PTA-OH (pKB = 5.82 +/- 0.36, three experiments). In radioligand binding studies, the binding of [125I]IBOP to guinea pig lung membranes prepared from perfused lungs was saturable, displaceable, and dependent upon protein concentration. Binding was optimal at pH 6.5 and was enhanced by the addition of mono- and divalent cations. The standard assay buffer was 25 mM 3-(N-morpholino)propanesulfonic acid, pH 6.5, 100 mM NaCl, 5 mM MgCl2. Binding was inhibited by pretreatment with dithiothreitol, N-ethylmaleimide, or beta-mercaptoethanol. Binding was unaffected by the addition of guanine nucleotide analogs at concentrations up to 300 microM. Analysis of the time course of binding of [125]IBOP at 30 degrees yielded k-1 = 0.0447 min-1, k1 = 2.49 x 10(8) M-1 min-1, and Kd = k-1/k1 = 180 pM. Computer analysis of equilibrium binding studies using nonlinear methods (LUNDON-1) revealed a single class of noninteracting binding sites with a Kd of 86.9 +/- 11.9 pM and a Bmax of 81.8 +/- 7.7 fmol/mg of protein (three experiments). [125I]IBOP binding to guinea pig lung membranes was inhibited by a series of TXA2/PGH2 receptor agonists and antagonists, with a rank order different from that previously determined for washed guinea pig platelets (Spearman's r = 0.686, p greater than 0.05). [125I]IBOP binding to guinea pig lung membranes was also inhibited by the prostanoids prostaglandin D2, prostaglandin E2, prostaglandin F2 alpha, and 9 alpha,11 beta-prostaglandin F2, all of which have been proposed to act at the TXA2/PGH2 receptor in lung.

The cognitive effects of alcohol abuse: a controlled study

It is now well established that there is an association between excessive alcohol consumption and psychological impairment. However, there has been some difficulty in the interpretation of results as the majority of studies have relied on reporting correlations in large subject samples. It was felt therefore that if subjects were matched by variables which had been found to be confounding in previous research, a clearer picture of the effects of alcohol on cognitive functioning could be drawn. Subjects in this study were therefore divided into a 'high' alcohol group (over 50 units per week), and a 'low' alcohol group (under 20 units per week). No patients who had previously been reported as suffering from cognitive impairment were included in this study as the purpose of this research was to examine the effects of alcohol on those heavy drinkers with no obvious impairment. They were matched by age, sex, socio-economic status and educational background. Heavy drinkers showed significant deficits on a number of cognitive tests compared with their matched controls. Furthermore, the subjects in the lower educational group showed a greater decrease in scores on several sub tests than those in the higher group.

Unrecognized left ventricular dysfunction in an apparently healthy cocaine abuse population

To determine the frequency and severity of clinically unrecognized left ventricular (LV) dysfunction related to cocaine use, 84 asymptomatic cocaine abusers underwent cardiac evaluation which included chest x-ray, electrocardiography (ECG), and radionuclide angiography after a two-week abstinence from cocaine use. LV dysfunction was discovered in 6/84 (7%). Regional wall motion abnormalities suggesting a localized myocardial abnormality were found in 2, whereas an ejection fraction less than 50% suggesting a more global process was noted in 4. An abnormal chest x-ray was found in only 1 subject and none had abnormal ECGs. In each of these cases, repeated and protracted use of cocaine was documented and the suggestion of cardiac dysfunction was supported by at least one other independent abnormal finding. In these 6 cases, the dysfunction was clinically unrecognized and unsuspected after routine evaluation. The significance of subclinical LV dysfunction in this population has not been determined and requires long-term study.

Nutrition in the older hospital patient

The importance of nutrition in the treatment of the older hospital patient has often been underestimated. This may be because of a failure to recognize the special nutritional problems of this age group. It is important to recognize that the older patient is more likely to be admitted to hospital suffering some degree of malnutrition and the nutritional consequences of the metabolic response to trauma may be more severe in this group. More attention needs to be placed on nutritional requirements and nutrient provision during rehabilitation. Adverse nutritional consequences of illness may be prolonged in the older subject and an extended period of nutritional supplementation may be required to produce benefit. It should be emphasized that adverse clinical consequences of nutritional deficit, and advantages of nutritional support, may not be evident in the short term. Long term follow up of nutritionally disadvantaged patients, and patients who have received specialized forms of nutritional support, will be required if the true contribution of nutrition to clinical outcome is to be evaluated.

Short-loop negative and positive feedback on ecdysone secretion by prothoracic gland in the tobacco hornworm, Manduca sexta

Ecdysteroid production by the prothoracic glands of the tobacco hornworm, Manduca sexta was found to be under feedback control by the ecdysteroids in hemolymph using both culture in vivo in diapausing pupae lacking the brain-corpora cardiaca-corpora allata complex and the prothoracic glands and culture in vitro. Prothoracic glands having relatively high activity in larvae, prepupae, or developing pupae were inhibited by ecdysone or 20-hydroxyecdysone. By contrast, prothoracic glands with low activity from feeding larvae, day 1 non-diapausing pupae and diapausing pupae were activated by both ecdysone and 20-hydroxyecdysone in vivo and in vitro. Dose-response studies on diapausing pupal glands showed that ecdysone was the most effective activator. These findings suggest that prothoracic glands are either stimulated or inhibited by ecdysone or 20-hydroxyecdysone, depending on both the secretory activity of the gland and the effective level of ecdysteroids in hemolymph. Thus, when the glands are first activated, the ecdysteroids that are secreted show a positive feedback on the glands to increase ecdysteroid output. Then the activated glands are turned off by the increasing 20-hydroxyecdysone titer in the hemolymph leading to the rapid decrease in ecdysteroid titer at the end of the molt period.

The effect of a low-fat diet on luteal-phase prolactin and oestradiol concentrations and erythrocyte phospholipids in normal premenopausal women

1. Fifteen normal premenopausal women followed a low-fat diet for a period of 2 months. 2. Daily fat intake was reduced from 81 g on their customary diet to 36 g on the low-fat diet. A significant reduction in total energy intake and an increase in the dietary polyunsaturated fat: saturated fat ratio was also observed. There was a significant decline in body-weight, percentage body fat and total serum cholesterol, but no significant change in high-density-lipoprotein-cholesterol. 3. Luteal-phase prolactin concentrations were not altered, but there was a significant decline in oestradiol concentrations on the low-fat diet. The proportion of erythrocyte inositol-phospholipid was increased on the low-fat diet and there was a significant increase in the 20:4 omega 6 (arachidonate) content of inositol-phospholipids. No significant changes in the content or fatty acid compositions of other phospholipid fractions were observed. 4. Further investigation of the effect of level and type of dietary fat on the content and fatty acid composition of membrane inositol-phospholipids are required. Long-term studies investigating the response of both prolactin and oestradiol to dietary fat reduction are also warranted.

A controlled trial of sip-feed supplements in elderly orthopaedic patients

The potential nutritional and clinical benefits of sip-feed supplements were investigated by means of a controlled trial in elderly female patients admitted for orthopaedic surgery. A nutritional risk assessment procedure (Nutritional Risk Questionnaire, NRQ) was used to identify patients who might benefit from supplementation. Patients identified as high risk who did not receive supplements showed significant losses in triceps skinfold thickness (TSF) and mid-upper arm muscle circumference (MUAMC) measurements during hospitalization. Such changes were not observed in high-risk supplemented patients, but significant losses of MUAMC were also recorded in a group of patients who failed to comply with the supplement. No differences in biochemical parameters, muscle function, or clinical outcome were observed between supplemented and unsupplemented and non-compliant patients. The problems of poor compliance to sip-feed supplements and failure to observe clinical benefit in supplemented patients are discussed.

Improved detection of healed myocardial infarction by Fourier amplitude and phase imaging in two projections: validation with MRI

Biplane Fourier amplitude and phase images from radionuclide ventriculograms were analyzed for the presence of regional wall motion abnormalities in 25 patients who had a total of 33 healed myocardial infarctions (nonviable scar tissue) documented by contrast ventriculography and ECG. This indirect evidence was validated by MRI, which permits direct visualization of healed myocardial infarction. The use of amplitude and phase images in both projections resulted in the detection of more healed myocardial infarctions (91%) than did the use of conventional radionuclide ventriculography with left anterior oblique images alone (67%), because inferior wall infarcts are more readily visualized in the left posterior oblique projection.

The captopril glomerular filtration rate renogram in renovascular hypertension

Administration of captopril to animals with two-kidney, one clip, renovascular hypertension (RH) lowers the glomerular filtration rate (GFR) in the clipped kidney. The authors therefore tested the hypothesis that a decrease in GFR after captopril administration would identify patients with RH. Total GFR was measured by the plasma disappearance of Tc-99m-diethylenetriaminepentaacetic acid (DTPA) after bolus injection and single-kidney GFR from renal uptake of DTPA assessed by renography. The authors studied six patients with arteriosclerotic RH who had strongly lateralizing renal vein renin levels and greater than 80% stenosis of the renal artery to that kidney. Results were contrasted with those of six patients with essential hypertension (EH) with a similar mean arterial blood pressure (MABP). Captopril (50 mg orally) increased total GFR (ml/min) in all patients with EH (102 +/- 8 to 120 +/- 12, P less than 0.005). However, GFR decreased in patients with RH (73 +/- 8 to 61 +/- 9, P less than 0.05) after captopril. Although the single-kidney GFR of patients with RH decreased in all six stenotic kidneys (27 +/- 4 to 21 +/- 5, P less than 0.02), it did not change consistently in the contralateral kidneys (45 +/- 8 to 40 +/- 6, N.S.). Clonidine (0.3 mg) also lowered MABP in patients with RH but, unlike captopril, it did not reduce total kidney GFR (75 +/- 10 to 79 +/- 11, N.S.). In conclusion, short-term captopril administration increases GFR in patients with EH, but decreases it in those with RH. This action is unrelated to its depressor response.(ABSTRACT TRUNCATED AT 250 WORDS)

Pectin delays gastric emptying and increases satiety in obese subjects

As pectin delays gastric emptying in normal subjects and satiety may be linked to the rate of gastric emptying, we designed this study to evaluate, in a group of obese subjects, the effect of adding pectin to a meal on gastric emptying, sensation of satiety, and postprandial plasma cholecystokinin and pancreatic polypeptide levels. We studied gastric emptying of solids in 9 adult obese subjects on 2 separate days in a randomized fashion. On day 1, 15 g of pectin was added to the meal, and on day 2 15 g of methylcellulose was added and served as control. Satiety was evaluated by an analogue rating scale. Pectin significantly delayed gastric emptying time [t1/2 = 116 +/- 23 min vs. 71 +/- 17 min observed with methylcellulose (p less than 0.001)]. Pectin also significantly increased subjects' sensation of satiety [98 +/- 7 vs. 74 +/- 17 (p less than 0.001)]. Postprandial release of cholecystokinin and pancreatic polypeptide was not modified by pectin. As pectin induces satiety and delays gastric emptying in obese patients, it may be a useful adjuvant in the treatment of disorders of overeating.

Biodistribution and radiation dosimetry of radioiodinated-SCH 23982, a potential dopamine D-1 receptor imaging agent

Radioiodinated-SCH 23982 is a potential agent for the imaging of dopamine D-1 receptors in the human brain. In vivo binding of [125I]SCH 23982 to D-1 receptors in rat brain was determined over 4 hr. The ratio of activity in striatum and frontal cortex to that in cerebellum increased over the first 2 hr to maximum values of 4.4:1 and 2.1:1, respectively. The percent injected dose in whole brain at 0.5 and 2 hr were 0.62 and 0.15, respectively. Administration of the antagonists propranolol (beta-1), prazosin (alpha-1), haloperidol (D-2) and ketanserin (5HT-2) did not significantly alter the striatum/cerebellum ratio; however, SCH 23390, a D-1 antagonist, totally blocked ligand uptake by striatum and frontal cortex. Biologic distribution data in the rat were determined after injection of 3 microCi of [125I]SCH 23982. 76% of the injected dose was excreted in 48 hr via the liver and kidneys. Internal radiation absorbed dose estimates to nine source organs, total body, the GI tract, gonads and red bone marrow were calculated for humans using the physical decay data for 123I. The critical organ was found to be the lower large intestine which received 1.1 rad/mCi of the administered dose. The total-body dose was 63 mrad/mCi. The data indicate that [123I]SCH 23982 should be a suitable agent for imaging the D-1 dopamine receptor in the human brain by single photon emission computed tomography.

Diagnostic uses of angiotensin-converting enzyme inhibitors in renovascular hypertension

The response to angiotensin-converting enzyme inhibitors (ACEIs) can be of considerable help in the diagnosis of human renovascular hypertension (RVH) in three settings. First, a particularly dramatic antihypertensive response or a decline in glomerular filtration rate (GFR), as indexed by a rise in serum creatinine or blood urea nitrogen concentrations, are useful clues to the presence of renovascular hypertension. Second, an exaggerated rise in plasma renin activity (PRA) after short-term captopril administration is a very promising screening test for this condition. Third, ACEI-induced changes in single-kidney hemodynamics (assessed by renography) may be helpful in confirming the diagnosis and offers the prospect of localizing the ischemic kidney.

Iron and zinc status in multiple sclerosis patients with pressure sores

Measurements of weighted dietary intakes and plasma determinations of albumin, iron, zinc, ascorbic acid and TIBC were carried out on twenty female multiple sclerosis patients in a long-stay hospital for disabled people. The group included ten patients with a recent history of pressure sores, closely matched with ten patients without pressure sores. Mean daily intake of carbohydrate was found to be higher in the non-pressure sore group whilst intake of zinc was lower in this group. Intakes of all other nutrients were comparable between the two groups. For both groups, intakes of energy, folate, vitamin D, iron and zinc were less than recommended values. Mean plasma levels of albumin and iron were towards the lower limit of the normal range, whilst that for zinc was considerably less than the normal range. Plasma TIBC was slightly above the normal range. Levels of plasma iron and zinc were significantly lower in the pressure sore group. The data indicate that severely disabled hospitalized patients with multiple sclerosis may be at risk of poor nutritional status. The results suggest that in the presence of pressure sores, there are increased requirements for specific nutrients, notably zinc and iron. Consideration is given to the possible value of supplementation of these individuals.

In vivo binding in rat brain and radiopharmaceutical preparation of radioiodinated HEAT, an alpha-1 adrenoceptor ligand

In vivo binding of [125I]-2-[beta-(3-iodo-4-hydroxyphenyl)ethylaminomethyl tetralone) ([125I]HEAT) to alpha-1 adrenoceptors in the rat brain was determined over 4 hr. Uptake in the thalamus and frontal cortex was approximately 0.1% injected dose per gram tissue. Thalamus/cerebellum ratios of 10:1 and frontal cortex/cerebellum ratios of 5:1 were found at 4 hr. Pretreatment with prazosin, an alpha-1 antagonist, completely inhibited the accumulation of [125I]HEAT in thalamus and frontal cortex; yet uptake of radioactivity was not significantly affected by antagonists and agonists for other receptors classes (propranolol, beta-1; apomorphine, D-1; spiperone, D-2). Binding of [125I]HEAT is saturable. At 4 hr, [125I]HEAT or [123I]HEAT was shown to be the only radioactive material in rat thalamus and frontal cortex. Iodine-123 HEAT and [125I]HEAT were synthesized as radiopharmaceuticals within 3 hr in 99% radiochemical purity.

Fetal growth, glucose tolerance and plasma insulin concentration in rats given a marginal-zinc diet in the latter stages of pregnancy

1. Wistar rats were fed on a control semi-synthetic diet throughout pregnancy, or a control diet in the first 2 weeks and a marginal-zinc diet in the 3rd week of pregnancy. On day 20, after an overnight fast, half the animals in each group were given glucose by gavage and the 0-30 min rise in blood glucose measured in tail blood. After 60 min blood was taken by cardiac puncture for glucose and insulin assay. Maternal pancreases were removed and the Zn contents measured. Fetuses from each litter were combined for wet/dry weights, protein and DNA determinations. 2. Plasma insulin concentration was higher, and glucose concentration and pancreatic Zn content lower, in pregnant v. non-pregnant animals of similar age, fed on the same diet. Pancreatic Zn content was lowest in the marginal-Zn group of pregnant rats. Fetuses from mothers fed on the marginal-Zn diet during the last week of pregnancy were slightly heavier than controls and had a significantly higher protein: DNA ratio. The 0-30 min rise in blood glucose was significantly greater in the marginal-Zn animals. 3. In a second experiment, pregnant rats were given similar diets to those used in the first study, but the marginal-Zn diet was given for a shorter period (days 15-19 of pregnancy). On day 19 the rats were meal-fed and on day 20, after an overnight fast, an oral glucose dose was administered. Tail-blood was taken at timed intervals up to 60 min post-dosing for glucose assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of octopamine and synephrine stereoisomers on alpha-adrenoceptors

1. The activities of the (-)- and (+)-forms of m- and p-octopamine and m- and p-synephrine on alpha 1-adrenoceptors from rat aorta and anococcygeus and alpha 2-adrenoceptors from rabbit saphenous vein were compared with those of noradrenaline (NA). 2. The rank order of potency of the (-)-forms on alpha 1-adrenoceptors from rat aorta and alpha 2-adrenoceptors was NA greater than m-octopamine = m-synephrine greater than p-octopamine = p-synephrine. The two m-compounds were 6 fold less active than NA on alpha 1-adrenoceptors from rat aorta and 150 fold less active on alpha 2-adrenoceptors. The two p- compounds were 1,000 fold less active than NA on both alpha 1-adrenoceptors from rat aorta and alpha 2-adrenoceptors. The rank order of potency of the (-)- forms on alpha 1-adrenoceptors from rat anococcygeus was NA = m-synephrine greater than m-octopamine greater than p-octopamine = p-synephrine. m-Octopamine was 4 fold less active than NA and (-)-m-synephrine. The two p- compounds were 30 fold less active than NA. 3. The rank order of potency of the (+)- forms was NA greater than m-octopamine greater than m-synephrine greater than p-octopamine greater than p-synephrine on both alpha 1- and alpha 2-adrenoceptors. The potency of each (+)- form was 1-2 orders of magnitude less than that of the (-) counterpart, the differences being greater for the stereoisomers of synephrine than for those of octopamine on both alpha 1- and alpha 2-adrenoceptors. 4. The yohimbine diastereoisomer antagonists, rauwolscine and corynanthine, were tested against (-)-NA and (-)-m-octopamine-induced contractions in both preparations. Based upon the known selectivities of these isomers for alpha-adrenoceptor subtypes, it is concluded that the rat aorta contains only alpha 1-adrenoceptors while the rabbit saphenous vein possesses predominantly alpha 2-adrenoceptors. 5. Ligand binding data for the octopamine and synephrine stereoisomers at alpha 1- and alpha 2-binding sites from rat cerebral cortex was also obtained. (-)-Forms were more active than (+)-forms. The rank order of affinity of the (-)-forms for both alpha 1- and alpha 2-binding sites was NA greater than m-octopamine = m-synephrine greater than p-synephrine greater than p-octopamine. The relative affinities of the members of the series against alpha 1-binding sites were very similar to their relative functional activities on rat aorta. However, the affinities of both m- and p-compounds relative to that of ( -)-NA were much greater at the x2-binding sites than were the relative activities in rabbit saphenous vein, possibly suggesting low intrinsic efficacy. Functional antagonist responses to NA by the (-)-octopamine and synephrines could not, however, be demonstrated on rat aorta or rabbit saphenous vein. 6. The activities of m-octopamine and m-synephrine were not significantly different from each other on either a,-adrenoceptors from rat aorta or x2-adrenoceptors; however, m-synephrine is more active than m-octopamine on a,-adrenoceptors from rat anococcygeus. Both m-octopamine and msynephrine can be considered to be naturally occurring x,-selective amines. However, if m- and poctopamine are co-released with NA in amounts proportional to their concentration, it is concluded that their activities on m,- and x2-adrenoceptors are too low to be physiologically significant.

Extracorporeal shock-wave lithotripsy: prevalence of renal stones 3-21 months after treatment

One hundred and four (70%) of the first 148 patients who underwent extracorporeal shock-wave lithotripsy (ESWL) at the University of Florida were evaluated for persistent or recurrent renal stone disease. Radiographs obtained 3-21 months after treatment showed that 53 (50%) of 106 treated kidneys were free of stones. In 48 of the 53 kidneys that contained stones, the stones were residual fragments dating from the period immediately after ESWL. New stones had developed in only five kidneys. The 50% incidence of stone-free kidneys 3-21 months after ESWL is less than the 65-90% rate reported by other institutions in the United States and Europe. After stone removal by ESWL, new stone formation occurs at a rate of 5%, which is much lower than the expected recurrence rate of 37-50%.

Extracorporeal shock-wave lithotripsy: long-term complications

Of 148 patients who had extracorporeal shock-wave lithotripsy (ESWL) for renal lithiasis in 1984, 21 (14%) returned after 17-21 months for renal function tests (21 patients) and blood pressure determination (20 patients). Quantitative radionuclide renography showed a statistically significant (p = .048) decrease in the percentage of effective renal plasma flow (ERPF) to the treated kidney. Two of these patients had developed hypertension requiring treatment but became normotensive when given medication. In the other patients there was a statistically significant increase in both systolic (p = .0002) and diastolic (p = .015) blood pressures. Information about blood pressure was also obtained from an additional 71 (48%) of the 148 patients; of the total 91 patients (61%) in whom blood pressures were obtained, seven (8%) had developed sufficiently severe hypertension to require treatment beginning within 21 months after ESWL. Side effects of ESWL for renal lithiasis include hemorrhage, edema, and acute tubular necrosis of the kidney. This form of renal trauma is associated with an immediate decrease in renal function of the treated kidney, and this decrease may be permanent. ESWL is also associated with the onset of hypertension, which may occur immediately or be delayed by several weeks or months. Although the pathogenesis remains unknown, hypertension is an important complication of ESWL in about 8% of patients.