Cognitive impairment among the elderly in a Korean rural community

Cognitive function among the elderly aged 65 or older was studied in a rural community of Korea. The prevalence rates of cognitive impairment were significantly higher in females (64%) than in males (33%). Sex differences of prevalence of both mild impairment (25% in males vs 45% in females) and severe (8% in males vs 19% in females) reached statistically significant levels. The prevalence of severe impairment increased with age, and the age-related increase was steeper after 80 in males and after 75 in females. The prevalence of mild impairment, on the other hand, did not increase so prominently with aging. From this point of view, it could be assumed that severe cognitive impairment may be highly related to real dementia, and that the elderly with mild impairment may consist of heterogenous groups associated with cognitive dysfunction of mild degree.

Functional pools of oxidative and glycolytic fibers in human muscle observed by 31P magnetic resonance spectroscopy during exercise

Quantitative probing of heterogeneous regions in muscle is feasible with phosphorus-31 magnetic resonance spectroscopy because of the differentiation of metabolic patterns of glycolytic and oxidative fibers. A differential recruitment of oxidative and glycolytic fibers during exercise was demonstrated in 4 of 10 untrained young men by following changes in phosphate metabolites. Concentrations of inorganic phosphate (Pi), phosphocreatine, and ATP were estimated in the wrist flexor muscles of the forearm at rest, during two cycles of three grades of exercise, and in recovery. At high work levels (40% of maximum strength), two distinct Pi peaks were observed and identified with Pi pools at pH 6.9 and pH 5.9-6.4, respectively. These could be accounted for as follows. At the lowest level of work (using 20% of maximum strength), early recruitment primarily of oxidative (type I) and possibly some intermediate (type IIA) muscle fibers occurs with relatively little net lactate production and consequently little decrease in pH. At higher work loads, however, primarily glycolytic (type IIB) muscle fibers are recruited, which have relatively high net lactate production and therefore generate a second pool of Pi at low pH. ATP depletion (35-54%) and Pi losses accompanied the reduction in ability to perform during the first exercise cycle. When the cycle of graded exercise was repeated immediately, the total Pi remained high but gave rise to only one peak at pH 6.8-7.0. These observations indicated exhaustion of glycolytic type IIB fibers, removal of lactate by high local blood flow, and sustained contractions largely by oxidative type I and IIA fibers. A functional differentiation of fiber types could also be demonstrated during recovery if exercise was stopped while two pools of Pi were still apparent. In the first 3 min of recovery, the Pi peak at pH 6.8-6.9 disappeared almost entirely, whereas the Pi peak at pH 6.0 remained unaltered, reflecting the faster recovery of oxidative type I fibers. The potential of magnetic resonance spectroscopy to characterize oxidative and glycolytic fibers, predict capacity for aerobic performance, and signal the presence of muscle pathology is discussed.

Stimulation of epidermal protein synthesis in vivo by topical triamcinolone acetonide

The rate of epidermal protein synthesis in vivo was determined in the hairless mouse by a method in which a large dose of [3H]phenylalanine (150 mumol/100 g body wt.) is administered via the tail vein. The epidermal free phenylalanine specific radioactivity rapidly rose to a plateau value which by 10 min approached that of plasma, after which it declined. This dose of phenylalanine did not of itself alter protein synthesis rates, since incorporation of co-injected tracer doses of [3H]lysine and [14C]threonine was unaffected. The fractional rate of protein synthesis obtained for epidermis was 61.6%/day, whereas values for liver and gastrocnemius muscle in the same group of mice were 44%/day and 4.8%/day respectively. When expressed on the basis of RNA content, the value for epidermis (18.6 mg of protein/day per mg of RNA) was approx. 3-fold higher than those for liver and gastrocnemius muscle. Topical administration of 0.1% triamcinolone acetonide increased the epidermal fractional protein synthesis rate by 33% after 1 day and by 69% after 7 days, compared with vehicle-treated controls. These effects were entirely accounted for by the increase in protein synthesis rates per mg of RNA. RNA/protein ratios were unaffected by this treatment.

Augmentation of postresection mucosal hyperplasia by plerocercoid growth factor (PGF). Analog of human growth hormone

Postresection villus hyperplasia is a major compensatory mechanism in the short-bowel patient. Substances capable of augmenting postresection mucosal hyperplasia could have therapeutic implications. Human growth hormone (hGH) and human growth hormone releasing factor (hGHRF) stimulate growth of the gastrointestinal tract; however, the diabetogenic actions of growth hormone limit its usefulness in clinical practice. Plerocercoid larvae of the tapeworm Spirometra mansonoides produce an analog of hGH void of diabetogenic side effects. We assessed effects of plerocercoid growth factor (PGF) on mucosal adaptation following 70% proximal jejunoileal resection in young rats. Mucosal weight, DNA, protein, and total sucrase activity per centimeter of bowel were increased in resected PGF-treated animals compared to resected controls. We conclude PGF augments intrinsic postresection mucosal hyperplasia following extensive intestinal resection.

Interactions of vitamin E and penicillamine in the treatment of hereditary avian muscular dystrophy

Our prior work demonstrated that penicillamine treatment of dystrophic chickens delayed the onset of symptoms, partially alleviated contractures, improved muscle function, and lowered serum creatine kinase. Penicillamine, a sulfhydryl compound with reducing properties, also prevented inactivation of glycolytic enzymes by protecting thiol groups. The present study shows that vitamin E enhances the therapeutic effects of penicillamine. Interaction of these two reductants is dose related. With vitamin E as adjunct therapy, the dosage level of penicillamine could be lowered by 50%, thereby minimizing side effects. The therapeutic rationale for two antioxidants is that penicillamine may act primarily in the cytoplasm to prevent oxidative damage, whereas the more hydrophobic vitamin E may protect membrane bilayers. Additionally, penicillamine may prevent collagen cross-linking and, deposition of insoluble collagen in muscle and thus decrease contracture formation. General applications of combined penicillamine and vitamin E therapy are discussed regarding prevention of free radical and oxidative damage in Duchenne dystrophy and a wide range of human diseases.

Percutaneous pulmonary valvuloplasty with a double-balloon technique

Percutaneous pulmonary valvuloplasty with a double-balloon technique was used in eight patients, aged 10-40 years, in whom valvuloplasty with a single 20-mm balloon resulted in inadequate dilatation of the stenosis. The diameters of the additional balloon varied from 10 to 20 mm. Balloons were inflated manually at about 30-45 psi (206.7-310.1 kPa) and deflated immediately after disappearance of the balloon waist. The mean peak systolic pressure gradient was 85 mm Hg +/- 37 before valvuloplasty, and it decreased to 38 mm Hg +/- 28 afterward (P less than .05). Double-balloon dilation and simultaneous computed tomography were done in two cardiac specimens from adult cadavers. At inflations at 30 and 45 psi (206.7 and 310.1 kPa), the outflow tract was elongated, and the balloons also deformed into ovoid shape at the lower pressure. The double-balloon technique appears to be safe and effective for relief of pulmonary valvular stenosis in those cases in which single-balloon technique is inadequate, especially in older children and adults.

Mediastinal tuberculous lymphadenitis: CT manifestations

An analysis was done of computed tomographic (CT) scans of 23 Korean patients who had presented with a mediastinal or hilar mass on plain chest radiographs and had subsequently been found to have tuberculous lymphadenitis. Most patients were young adults. Findings of pulmonary tuberculosis were seen on plain radiographs in 14 patients. On CT, findings were of an overwhelming preponderance of involvement of the right paratracheal and tracheobronchial nodes. After injection of contrast medium, nodes larger than 2 cm in diameter invariably showed central areas of relative low density and peripheral rim enhancement. Enhanced walls were usually irregular in thickness. Some smaller nodes did not show low-density areas, but instead showed varying degrees of homogeneous enhancement. Although metastatic nodes can be of low density, experience in this study suggests that mediastinal lymphadenopathy in a young adult with the CT findings described above is characteristic enough to support a diagnosis of tuberculosis.

Percutaneous removal of residual intrahepatic stones

In the Orient there is a high frequency of residual intrahepatic stones after biliary tract surgery. Percutaneous removal of residual intrahepatic stones was attempted in a group of 74 patients. Stones were exclusively intrahepatic in 57 patients, whereas 17 patients also had stones in the common bile duct. Biliary strictures were present in 60 cases (81%). A combination of techniques was used, including preshaped angulated catheters, irrigation-suction, balloon dilation of strictures, and crushing of large stones. In 36 cases all stones were removed and in 14 cases most stones were removed, for a success rate of 67.6%. Biliary stricture was the factor most often responsible for failure.

Renal arterial embolization with absolute ethanol

Twenty separate infarction procedures with absolute ethanol were performed on eighteen renal tumors in seventeen patients at Department of Radiology, Seoul National University Hospital since 1982. Fifteen were hypernephroma cases and two were angiomyolipoma cases. The indications for renal infarction were the preoperative interruption of renal arterial flow in eight cases of hypernephroma, and primary therapy or palliation of symptoms in seven cases of hypernephroma and two cases of angiomyolipoma. Average 15ml of absolute ethanol was injected for renal arterial embolization at a rate of 1-2 ml/sec via balloon occlusion catheter or superselective administration technique. Though the long-term beneficial effect on survival was not confirmed, transcatheter embolization with absolute ethanol was suggested to be used as indispensible treatment in preoperative and inoperable or symptomatic cases of renal tumor.

Augmentation of mucosal adaptation following massive small-bowel resection by 16,16-dimethyl-prostaglandin E2 in the rat

Survival following massive resection of the small intestine is often possible due to substantial hyperplasia of the mucosal surface in the remaining small intestine. While nutrients provide the major stimulus for hyperplasia in the clinical setting, the availability of drugs to augment this process would have obvious therapeutic implications. We evaluated the ability of 16,16-dimethyl-prostaglandin E2 (PGE2 to augment mucosal hyperplasia following massive small bowel resection in the rat. Three groups of 7 Sprague-Dawley rats, 160 g body weight, were subjected to 70% jejunoileal resection. One group was given 150 micrograms/kg of 16,16-dimethyl-PGE2 intragastrically twice daily, a second group 75 micrograms/kg subcutaneously, and a third group was untreated. After 17 days, segmental evaluation of mucosal mass in the remaining small intestine was determined by measuring mucosal protein, DNA, and disaccharidase levels. A significantly greater increase in mucosal mass was developed in the duodenum proximal to the anastomosis in both treatment groups, but neither the proximal nor distal ileum demonstrated significantly more adaptation. Histological examination in the duodenum confirmed the presence of a greater adaptive response in both the intragastrically and subcutaneously treated animals. 16,16-dimethyl-PGE2 appears to augment mucosal adaptation following massive small bowel resection in the rat, primarily in the very proximal small intestine.

Effect of zinc deficiency on mucosal hyperplasia following 70% bowel resection

We evaluated the effect of zinc deficiency on the development of mucosal hyperplasia in male Sprague-Dawley rats following 70% small-bowel resection: 20 underwent 70% jejunoileal resection, another 20 were sham operated. Half of each group were made zinc deficient by force-feeding technique. Operations were then performed, and feedings were continued for another 9 days. While mucosal weight did not differ between zinc-deficient and zinc-replete animals, whether or not they underwent resection, mucosal protein and DNA levels were decreased in both resected and sham-operated, zinc-deficient animals. Functional indices were also affected. Maltase activities were decreased in zinc-deficient animals in the midileum. Mucosal zinc-dependent enzymes, alkaline phosphatase and leucine aminopeptidase, were likewise depressed in zinc-deficient animals. Findings suggest that zinc deficiency in short-bowel syndrome will likely impair mucosal hyperplasia.

Effect of pure zinc deficiency on glucose tolerance and insulin and glucagon levels

The effect of zinc deficiency on glucose tolerance was investigated using intragastric force feeding to obviate decreased food intake and altered eating patterns. Three groups of weanling male Sprague-Dawley rats were fed a purified zinc-deficient diet: zinc-deficient, ad libitum-fed animals (ZDA) were offered powdered zinc-deficient diet; zinc-replete, force-fed controls (ZRF) were tube fed a diet blended with water containing 25 ppm of zinc; zinc-deficient, force-fed animals (ZDF) were similarly tube fed the zinc-deficient diet. The ZRF and ZDF groups received a diet of identical amount based on the intake of ad libitum-fed, zinc-replete rats. After 8 days of feeding, the ZDF group had impaired glucose tolerance curves, yet blood insulin and glucagon levels were normal. The ZDA group had normal glucose tolerance with low insulin levels compared with the ZRF group. The islet cell morphology among the three dietary groups were similar. These results suggest that the glucose intolerance observed in ZDF rats is not due to altered blood insulin and glucagon levels but rather to peripheral resistance to insulin action.

Transcatheter renal arterial embolization with the mixture of ethanol and iodized oil (Lipiodol)

We induced experimental renal arterial embolization with the radiopaque solution of ethanol and iodized oil (Lipiodol) in 35 rabbits to evaluate the capability of the mixture to induce renal ablation. Serial renal angiography and plain abdominal radiography were performed immediately, one week and two weeks after embolization. Neither pure Lipiodol nor a 50% ethanol solution caused renal embolization. However, infusion of 50% and 75% ethanol-Lipiodol solutions resulted in embolization equal to that caused by absolute ethanol. The 50% ethanol-Lipiodol solution was so radiopaque that we could easily observe the embolization process during fluoroscopy. Renal arterial embolization with the 50% ethanol-Lipiodol solution was successful in three patients with hypernephroma. Our results suggest that a 50% ethanol-Lipiodol solution is radiopaque and an effective agent for renal arterial embolization.

Effects of dietary carbohydrate on hepatic gluconeogenesis in BHE rats

The effects of feeding different carbohydrates on hepatic gluconeogenesis in BHE rats was studied. Three experiments were conducted that differed only in the aspects of gluconeogenesis examined. In experiment 1, gluconeogenesis and ketogenesis by hepatocytes isolated from 48-h starved rats were determined. In experiment 2, the activities of selected gluconeogenic enzymes were determined in starved and nonstarved rats. In experiment 3, the levels of the various metabolites of glycolysis and the citric acid cycle were determined in nonstarved rats. Rats were fed diets containing starch, maltose, glucose, sucrose or an equimolar mixture of glucose and fructose. In starved rats, gluconeogenesis was less in starch-fed rats than in rats fed any of the sugar diets. These same diet differences, with few exceptions, were also observed in ketogenesis. Glucose 6-phosphatase activity was lower in nonstarved rats fed starch and maltose than in rats fed glucose, sucrose, or glucose and fructose. These same nonstarved rats also had lower phosphoenolpyruvate carboxykinase and higher glutamate pyruvate transaminase activities than rats fed the other diets. In the starved rats, the diet differences were erased. Starved rats had lower activities of these gluconeogenic enzymes than nonstarved rats. Diet differences in the levels of the different metabolites in nonstarved rats were observed. The results show that dietary carbohydrate can influence gluconeogenesis. However, the mechanism of their effect is as yet unknown.

Effects of isolated zinc deficiency on the composition of skeletal muscle, liver and bone during growth in rats

We investigated the effects of zinc deficiency on body composition by using intragastric force-feeding to obviate decreased food intake and altered eating patterns. Weanling male Sprague-Dawley rats were fed a purified zinc-deficient diet: the ad libitum-fed control group (AL; eight rats) was given powdered diet and water containing 25 ppm zinc; the zinc-replete group (ZN; nine rats) was force-fed a diet blended with water containing zinc in an amount of equal caloric intake to the AL group and allowed access to water containing zinc. The zinc intake of ZN rats was approximately twice that of AL rats based on water intake. The zinc-deficient group (ZD; 13 rats) was fed similarly to the ZN group except deionized water was used for diet preparation and drinking water. After 8 d, body and muscle weight were lower in the ZD group than in the ZN group. Femur weights were similar in the two groups. Serum, liver and femur zinc concentrations were 85, 22 and 42% lower, respectively, in the ZD group than in the ZN group. Serum glucose, relative liver weight, liver glycogen and liver lipids were higher, but muscle and liver DNA were lower in the ZD group than in control groups.

CT findings of lobar bronchioloalveolar carcinoma

The CT findings in a case of lobar bronchioloalveolar carcinoma included stretching, spreading, and uniform narrowing of the involved bronchi without obstruction.

Effects of short-term isolated zinc deficiency on intestinal growth and activities of several brush border enzymes in weaning rats

To determine whether zinc has a specific role on intestinal growth and function, three groups of male weanling Sprague-Dawley rats were fed a semipurified zinc-deficient diet: ad libitum fed group received powdered diet and water containing 25 ppm of zinc; force fed (ZN, ZD) groups were fed identical amounts of diet to the ad libitum fed group by intragastric infusion three times per day. The diets were aqueous suspensions made with either deionized water (ZD) or water containing 25 ppm of zinc (ZN), and additional drinking water with (ZN) or without zinc (ZD) was offered ad libitum. Rats were sacrificed after 8 days of feeding. The ZD group showed growth arrest, perioral and periorbital dermal lesions, and abdominal distention within 8 days of feeding. Mucosal DNA, protein, sucrase, maltase, lactase, leucine aminopeptidase, and alkaline phosphatase were significantly decreased in the ZD group, whereas intestinal length, weight, and mucosal weight were unaltered. These results suggest that short-term isolated zinc deficiency impairs growth, digestion, and absorption in the rat small intestine, even in the absence of associated protein calorie malnutrition.

Sonographic evaluation of inferior vena caval obstruction: correlative study with vena cavography

Sonographic findings of obstruction of the inferior vena cava (IVC) in 14 cases are described and correlated with venographic findings. The causes of the obstruction were membrane (five cases), thrombosis (three), and intraluminal tumor invasion by hypernephroma, hepatoma, and adrenal carcinoma in six. Sonographic examination revealed highly echogenic segmental obliteration or membrane in membranous obstruction and echogenic intraluminal mass in thrombotic occlusion. Absence of an identifiable patent lumen in a technically satisfactory study was another finding in thrombotic obstruction. On real-time sonograms, the normal respiratory changes of the IVC were absent when there was complete occlusion. Transhepatic collaterals, patency of other segments of the IVC, and associated malignancy were additional sonographic findings. Comparison to venography suggested that in addition to ease and safety, sonography has advantages in delineation of the cephalad extent of occlusion, dynamic evaluation of the IVC below the obstruction, and the simultaneous evaluation of adjacent organs.

In vivo imaging and evaluation of platelet accumulation vs. time at arterial injury site

The feasibility of quantitatively imaging platelet deposition over time following angioplasty of the abdominal aorta in a rabbit model, with and without antiplatelet treatment, was investigated. Ten male 3-4 kg rabbits were balloon de-endothelialized and placed on 2% cholesterol diet for eight weeks. Group A was untreated. In Group B, donors and recipients were treated with aspirin (5 mgm/kg) prior to and after angioplasty. Platelets were labelled with indium-111. Labelled platelets were injected just prior to PTA and images of 100,000 counts were obtained immediately and at 30 minutes, 1 hour, and 24 hours. In Group A, increased activity of angioplasty site vs. nonangioplastied aorta was seen immediately. This focal increase became more marked in hypercholesterolemic animals over the 24-hour period. In Group B, both hypercholesterolemic and normocholesterolemic, no focal uptake could be documented on sequential scans. This method and model are promising for in vivo evaluation of platelet-vessel wall interactions, in the setting of angioplasty and antiplatelet therapy.

Arterial manifestations of Behçet disease

Behçet disease is an uncommon systemic process that appears most often in the third or fourth decade of life. It is characterized by recurrent orogenital ulcers and ocular and cutaneous inflammatory lesions. Cardiovascular involvement, which may be arterial or venous, is rare but carries a particularly poor prognosis. Three new cases are reported, and they are characterized by typical orogenital and cutaneous manifestations and associated severe vasculitis. The arterial findings in these cases were occlusions and aneurysms and pseudoaneurysms of the aorta and pulmonary, brachiocephalic, and visceral arteries. From these cases and those previously reported, arterial involvement in Behçet disease can be characterized by saccular aneurysms or occlusions of multiple large vessels in young adults.

Interactions and spatial arrangement of spin-labeled NAD+ bound to glyceraldehyde-3-phosphate dehydrogenase. Comparison of EPR and X-ray modeling data

The spatial arrangement of coenzyme NAD+ in remote and adjacent binding sites in various stoichiometric complexes with tetrameric glyceraldehyde-3-phosphate dehydrogenase from rabbit muscle was examined via EPR spectroscopy. An adenosine N6-15N,2H17 spin-labeled derivative of coenzyme NAD+ (SL-NAD+) was chemically synthesized for this work. The spectral simplifications and narrow line widths afforded by 15N and 2H substitution enabled experimental EPR spectra to be deconvoluted into their three component spectra: (a) unbound coenzyme, (b) bound coenzyme without adjacent site occupied, and (c) bound coenzyme with adjacent site occupied. Binding of SL-NAD+ in adjacent active centers of R axis-related subunits resulted in resolved dipolar interactions which characterized intersubunit distances. Binding to distant subunits related by the P and Q axes gave no dipolar interaction. Once the first NAD+ site was occupied, EPR spectra at various stoichiometries provided evidence for nonpreferential spatial binding of SL-NAD+ to the three unoccupied sites. EPR spectral simulations indicated a separation of 12.8 A for the unpaired electrons of spin label moieties of R axis-related coenzymes. Molecular modeling based on x-ray crystallographic data predicted 11-13 A. The angles and distance relating to interacting spin-labels were calculated from atomic coordinates based on molecular modeling of both anti-anti and anti-syn (adenine-ribose) conformations of SL-NAD+. Computer-generated line shapes indicated best agreement with experimental EPR results when the anti-anti geometry was employed. Comparison of EPR spectra from soluble and ammonium sulfate-precipitated enzymes indicated that the NAD+-binding domains are positioned equivalently in the two physical states. Since the observed dipolar line shapes are critically dependent on the distance and geometry relating to the interacting SL-NAD+, these data provide direct evidence for a high degree of conservation of quaternary structure of the enzyme in the hydrated crystalline state. Studies on the enzyme isolated from human erythrocytes also indicated a close correlation with the rabbit muscle enzyme in both the arrangement of NAD+-binding domains and negative cooperativity of coenzyme binding.

Permeation of long-chain fatty acid into adipocytes. Kinetics, specificity, and evidence for involvement of a membrane protein

This study extends our earlier work (Abumrad, N. A., Perkins, R.C., Park, J.H., and Park, C.R. J. Biol. Chem. 256, 9183-9191) which showed that oleate permeates the plasma membrane of the rat adipocyte principally by a transport process with the characteristics of facilitated diffusion. In the present study, fatty acid (FA) transport is characterized with regard to its specificity and susceptibility to inhibition by protein modifiers. The kinetics of competitive inhibition for transport of oleate and stearate are shown under conditions where complications due to competition for binding of FAs to the albumin in the medium are minimized. Stearate inhibits influx of tracer oleate with a Ki that closely approximates its Km and, conversely, oleate inhibits similarly the influx of tracer stearate. Specificity of the FA transport system is shown in studies using a variety of natural FAs of different chain length, or FA analogues. Oleate (Km = 0.06 microM), stearate (Km = 0.16 microM), linoleate (Km = 0.22 microM), palmitate, (Km = 0.2 microM), and laurate (Km = 1.5 microM) are good substrates, but octanoate is not transported. An oxazolidine ring on C-5 but not on C-16 of stearate blocks binding to the transporter. Methylation of the carboxyl function but not alpha-bromination inhibits transport. These studies suggest that a FA must have a hydrocarbon chain of at least nine carbons and a free carboxyl function to be recognized by the transporter. FA transport does not require Na or ATP. Pronase but not trypsin treatment of intact cells reduces fatty acid influx. Transport is insensitive to maleimides. It is strongly and irreversibly blocked by pretreatment of the cells with the stilbene compounds, 4,4'-diisothiocyanostilbene-2,2'-disulfonate and 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid, but only slightly inhibited by dipyridamole. Polyacrylamide gel electrophoresis of plasma membrane proteins from cells treated with [3H] 4,4'-diisothiocyanostilbene-2,2'-disulfonate shows a peak of radioactivity at about Mr = 85,000. When cells are incubated in various concentrations of this agent, the counts recovered in the peak reach a maximum coincident with maximum inhibition of transport. We conclude that permeation of the plasma membrane of the adipocyte by long-chain FAs at physiological concentrations is mediated by a protein transporter with distinct specificity requirements.

An electron-electron double-resonance study of interactions between [14N]- and [15N]stearic acid spin-label pairs: lateral diffusion and vertical fluctuations in dimyristoylphosphatidylcholine

Vertical fluctuations of the terminal methyl groups of stearic acid acyl chains toward the surface of dimyristoylphosphatidylcholine (DMPC) bilayers have been investigated by using spin-label electron-electron double-resonance ( ELDOR ) methodology. Spin-label pairs consisting of two populations of stearic acid spin-labels were employed, each at 0.25 mol% concentration, where the nitroxides of the first population were 15N substituted and the nitroxides of the second contained 14N. Various combinations of labels with the nitroxide moieties located at carbons 5, 12, or 16 (C5, C12, C16) were used. ELDOR permits measurement of collision frequencies between the two constituents of the pair, for example, between 15N spin-labels at C5 and 14N labels at C16. Intramolecular contributions to the ELDOR effect including nitrogen nuclear relaxation are eliminated by the use of spin-label pairs. Above the main phase transition temperature, bimolecular collisions between C5 and C16 occur with about half the frequency of C16:C16 collisions. It is concluded that vertical fluctuations are very pronounced. A dependence of these fluctuations on temperature and pH has been observed. Lateral diffusion constants calculated from the bimolecular collision frequencies of C16:C16 pairs are 4.56 X 10(-8), 5.77 X 10(-8), and 8.09 X 10(-8) cm2/s at 27, 37, and 47 degrees C. These values are in good agreement with previous measurements of lipid diffusion in DMPC.

The role of the nicotinamide moiety of NAd+ for negative cooperativity in glyceraldehyde-3-phosphate dehydrogenase as studied by spin-labeled cofactors

Two derivatives of NAD+ spin-labeled at N6 or C-8 of the adenine ring have been shown previously to be active coenzymes of glyceraldehyde-3-phosphate dehydrogenase (D-glyceraldehyde-3-phosphate: NAD+ oxidoreductase (phosphorylating), EC 1.2.1.12). When more than two equivalents of either spin-labeled NAD+ are bound to the tetrameric enzyme, spin-spin interaction is observed in the ESR spectra (Deparade, M.P., Glöggler, K. and Trommer, W.E. (1981) Biochim. Biophys, Acta 659, 422-433). After reduction of enzyme-bound NAD+ spin-labeled at C-8 to the corresponding NADH derivative, the additional peaks due to this spin-spin interaction disappear, which implies that the distance between the two radicals increases. It is proposed that the coenzyme slide further towards the active site upon reduction. ADPR spin-labeled at C-8 binds non-cooperatively, exhibiting a dissociation constant of Kd = 33 microM. Even with 3.5 equivalents bound to the enzyme, spin-spin interaction is not observed. AMP spin-labeled at C-8 combines with two sites per monomer, or a total of eight per tetramer. The respective dissociation constants are Kd1 = 30 microM and Kd2 - 2.3 mM. Phosphate competes with AMP bound to the weak site. Spin-spin interaction is not observed. ATP spin-labeled at C-8 is bound about 10-fold tighter than the corresponding AMP derivative. Four equivalents of ATP are bound per tetramer, but it exhibits no spin-spin interactions. It is concluded that the structure of the pyridine moiety of the coenzymes plays a role in orienting the adenine ring and, thus, affects the cooperativity. The N6 derivative of NAD+ also shows spin-spin interaction; however, only data for the C-8 derivatives are shown in detail.

Etiology of viral hepatitis in American soldiers

To define better which types of hepatitis are prevalent among American soldiers, the authors studied 413 separate episodes of acute viral hepatitis among 412 soldiers admitted to US Army hospitals during 1978-1979. Most soldiers (68.8%) had acute hepatitis B (estimated annual hospitalization rate: 5.41/1000 soldiers in West Germany, 2.51/1000 in South Korea, less than 1/1000 in the United States). Subtype ayw was predominant in Germany, whereas adr was predominant in South Korea. Hepatitis B was more often associated with contact history or parenteral use of drugs in West Germany than in South Korea (p less than 0.001). Non-A, non-B hepatitis accounted for 27% of cases in West Germany (2.16/1000), but only 3% in South Korea (0.11/1000); hepatitis A only 15% in South Korea (0.48/1000) and 1% in West Germany (0.08/1000). These findings indicate that hepatitis B is the most prevalent form of viral hepatitis among US soldiers worldwide but also suggest substantial differences in the epidemiology of this infection in South Korea and West Germany. Such data will be useful in developing hepatitis B immunization policy within the military.

Equilibrium binding of spin-labeled fatty acids to bovine serum albumin: suitability as surrogate ligands for natural fatty acids

Electron paramagnetic resonance (EPR) and saturation transfer EPR (ST-EPR) spectroscopies were used to characterize the binding of spin-labeled fatty acid (SLFA) to bovine serum albumin (BSA). Association constants of three stearic acid derivatives labeled with a nitroxyl radical at C-5, C-12, or C-16 were estimated by EPR spectroscopy as the ratio of SLFA to BSA was increased from about 0 to 9. The values were compared to those for unmodified stearate. With all three SLFA, it was apparent that the nitroxyl residue modified the binding pattern. For SLFA:BSA ratios up to 1, which probably involves the site(s) on BSA most specific for long-chain FA, the C-16 derivative bound with an affinity similar to that of the natural FA. At higher ratios, the association constants for this SLFA were lower than those for stearate. The C-12 and C-5 derivatives showed only low-affinity binding relative to stearate. The spectral parameter, W, was constant for SLFA:BSA ratios between 0 and 1 in the case of C-16 compound, indicating physical homogeneity of the high-affinity binding site. At higher ratios, the spectra changed progressively, indicating inhomogeneity of the lower affinity binding sites although parallel changes in association constants were not observed. Changes in W due to Heisenberg spin exchange were ruled out. By examining the mobility profile of the bound SLFA by both EPR and ST-EPR techniques, it was shown that the nitroxyl group was maximally immobilized when attached near the center of the carbon chain of the bound SLFA.

Effect of interferogram smearing on atmospheric limb sounding by Fourier transform spectroscopy

A method is presented for analyzing an absorption spectrum obtained from the interferogram measured by an interferometer operated in the solar occultation mode. In this mode the complete interferogram is smeared with various components of individual interferograms generated by rays passing through different tangent altitudes. It is shown that the effective tangent altitude of the spectrum is the altitude at which the center fringe of the interferogram is recorded and that the other components of the interferogram only define the instrument line shape. The interferogram smearing effectively creates strong sidelobes on absorption lines so that a strong apodization on the interferogram is recommended for the solar occultation experiment. These concepts are applied to retrieve pressure and temperature simultaneously from stratospheric absorption spectra in the CO(2) 4.3-microm band obtained by a balloon-borne interferometer in 1976 over Palestine, Tex. Included in the analysis of the CO(2) 4.3-microm band are the continuum absorptions by the pressure-induced N(2) fundamental band and by far wings of the CO(2) v(3) band. The CO(2) absorption line is corrected by a sub-Lorentzian function. Excellent agreement is found between the observed and simulated spectra.

The synthesis of deuterium-substituted, spin-labeled analogues of AMP and NAD+ and their use in ESR studies of lactate dehydrogenase

Two spin-labeled analogues of AMP and NAD+ were synthesized, in which a perdeuterated nitroxide radical (4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl, TEMPAMINE) was attached to C-6 or C-8 position of the adenine ring. The ESR spectra of these derivatives exhibit a 4-fold increase in sensitivity and a concomitant decrease in line-width as compared to the corresponding protonated analogues. The improved resolution of composite spectra consisting of freely tumbling and immobilized components is demonstrated in ternary complexes of the spin-labeled NAD+ derivatives with lactate dehydrogenase (L-lactate:NAD+ oxidoreductase, EC 1.1.1.27) and oxalate.

Three-dimensional digital subtraction angiography

A dye-edge tracking algorithm was used to determine the corresponding points in the two images (anterior-posterior and lateral) of the digital subtraction biplane angiography. This correspondence was used to reconstruct three-dimensional images of cerebral arteries in a dog experiment and a clinical observation. The method was tested by comparing the measured image of oblique view to the computed reconstructed image. For the present study, we have developed three new algorithms. The first algorithm is to determine the corresponding dye-edge points using the fact that the density of contrast media at the moving edge shows the same changing pattern in the two projection views. This moving pattern of dye-edge density is computed using a matching method of cross correlation for the two sequential frames' dye density. The second algorithm is for simplified perspective transformation, and the third is to identify the corresponding points using a complementary method for locating the approximate points on the small vessels. The present method can be applied to compute the velocity of blood flow using the dye-edge displacement and the three-dimensional distance data.

Stratospheric measurements of continuous absorption near 2400 cm(-1)

Solar occultation spectra obtained with a balloon-borne interferometer have been used to study continuous absorption by N(2) and CO(2) near 2400 cm(-1) in the lower stratosphere. Synthetic continuum transmittances, calculated from published coefficients for far-wing absorption by CO(2) lines and for pressure-induced absorption by the fundamental band of N(2), are in fair agreement with the observed stratospheric values. The continuum close to the nu(3) R-branch band head of CO(2) is sensitive to the CO(2) far-wing line shape. Therefore, given highly accurate knowledge of the N(2) continuum from laboratory data, high-resolution stratospheric spectra provide a sensitive means for in situ testing of various air-broadened CO(2) line shapes at low temperatures.