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Objectives: The purpose of this study was to examine the time requirements and costs of recruiting older adults for participation in a medical center-/university-sponsored, home-based nutrition education study. A two-step recruitment strategy consisting of an introductory letter followed by a telephone call was used., Design: A random selection of 1300 individuals aged 60 to 74 years was drawn from a patient database of a large, rural, tertiary care hospital to receive introductory letters and recruitment telephone calls. One week after the mailing, potential subjects were contacted by trained interviewers and asked to participate in a home-based nutrition education study., Participants: Men and women, aged 60 to 74 years, whose names appeared in a rural, tertiary care hospital database., Measurements: Recruitment rate, time required for recruitment by telephone, and cost of the combined mailing and telephone recruitment effort., Results: Of the 1300 individuals selected, 1077 (83%) people were contacted by phone and 223 (17%) people were unable to be reached. A total of 2895 calling attempts were required to determine the recruitment status of those identified as potential participants. Of those reached by phone, the recruitment rate was 45%. The total cost (mailing, telephone, and database management) per recruited subject was $8.56., Conclusion: This study has helped to establish the costs of recruitment for home-based education interventions using a two-step strategy of an introductory mailing and follow-up telephone interview.

Aim: Can useful lengths of vein be retrieved from varicose vein stripping procedures; is it necessary to sterilise this tissue prior to use as vein allografts?, Method: Stripped long saphenous vein was retrieved at operation. Vein samples were cultured using direct plate inoculation and enrichment culture. Further samples were immersed in two low concentration antibiotic solutions and recultured. Smooth muscle viability was assessed after antibiotic immersion and storage by cryopreservation., Results: High quality vein could be retrieved by vein stripping. Vein segments grew skin commensals on enrichment culture despite negative cultures with standard media plate inoculation (Chi-squared = 53.34 1 d.f. p < 0.001). Low concentration antibiotic solutions sterilised processed vein. Smooth muscle cell viability was reduced by cryopreservation, Mann-Whitney p = 0.008 (control 98% S.E. 0.93 vs. cryopreserved 64% S.E. 6.58), but prior exposure to antibiotics did not compound this effect., Conclusion: Useful lengths of vein grafts can be retrieved from varicose vein stripping procedures. Venous segments are frequently contaminated by skin commensals. Enrichment culture is required to detect contamination. Low concentration antibiotics sterilise venous-tissue without affecting smooth muscle cell viability.

The time-resolved fluorescence emission and decay of fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH) was used to characterize equilibrium and dynamic bilayer structural properties of symmetrically substituted phosphatidylcholines (PCs) with acyl chains containing no, one, four, or six double bonds and mixed-chain phosphatidylcholines with a saturated sn-1 chain and one, four, or six double bonds in the sn-2 chain. Both the Brownian rotational diffusion (BRD) model and the wobble-in-cone model were fit to all differential polarization data, and the descriptions of the data provided by the BRD model were found to be statistically superior. Global analysis of differential polarization data revealed two statistically equivalent solutions. The solution corresponding to a bimodal orientational distribution function, f(theta), was selected based on the effects of temperature on f(theta) and previous measurements on fixed, oriented bilayers. The overall equilibrium acyl chain order in these bilayers was analyzed by comparing the orientational probability distribution for DPH, f(theta) sin theta, with a random orientational distribution. Orientational order decreased and probe dynamics increased in mixed-chain species as the unsaturation of the sn-2 chain was increased. The degree of orientational order dropped dramatically in the dipolyunsaturated species compared with the mixed-chain phosphatidylcholines, which contained a polyunsaturated sn-2 chain. In terms of both orientational order and probe dynamics, the differences between the highly polyunsaturated species and the monounsaturated species were much greater than the differences between the monounsaturated species and a disaturated PC.

One of the most important tasks of the perfusionist is the proper assembly of the extracorporeal circuit (ECC) prior to the initiation of cardiopulmonary bypass (CPB). The ECC is usually assembled, primed and debubbled 30 minutes to one hour prior to the patient entering the operating room. But there are occasions when the ECC may have been set up and the previously scheduled procedure cancelled. Perfusionists in this situation have found themselves in a quandary; dispose of the ECC because of required nursing compliance and the sterility question, or keep it and use it later because of the economic impact on the "bottom line". Some hospitals may have satisfactorily answered the question of ECC sterility after 24 hours without observation, but the few reported papers regarding this issue, and our desire to save these circuits, inspired us to find out if they were in fact sterile after having been open for a long period of time. The purpose of this study was to evaluate ECC sterility using an open reservoir oxygenator, over a time period of seven days. After obtaining 792 bacterial cultures from three sites within the ECC, the study was terminated. There were no positive bacterial cultures during the study period. Assuming there is no deliberate contamination, pump circuits assembled in an unused operating room can be maintained sterile for a period of seven days.

Objective: To assess the dietary intake of children with IDDM and to determine whether the intake meets the current nutritional recommendations for children with IDDM., Research Design and Methods: A total of 66 children with IDDM who were < 10 years of age were recruited from two suburban Pennsylvania hospitals. To collect dietary intake data, subjects were asked, via telephone interview, to complete three random-day 24-h dietary recalls. Data were analyzed for the content of nutrients and other food components by a computerized database program. Intakes were expressed as a 3-day average intake for each subject., Results: Overall mean intake of protein and cholesterol approximated the current recommendations. The mean intake of saturated fat exceeded recommendations, while fiber intake was less than the recommended level. Many of the children consumed levels of saturated fat well above recommendations. Energy, vitamin, and mineral intakes were adequate for the overall sample. However, from 10 to 40% of the sample had an inadequate intake of vitamin D, vitamin E, and zinc. The percentage of those with inadequate intakes of these nutrients decreased with age., Conclusions: These data suggest that, on average, among this sample of children with IDDM aged < 10 years, adherence to the current nutritional recommendations for children with IDDM was adequate, but some individual children had intakes that were not consistent with the recommendations for optimal management of IDDM.

The visual pigment rhodopsin is a prototypical member of the G protein-coupled receptor superfamily. In this study, we have investigated the effect of a series of n-alcohols on the formation of metarhodopsin II (MII), the photoactivated conformation of rhodopsin, which binds and activates transducin. When rhodopsin was photolyzed in the presence of several n-alcohols, increased MII formation was observed in the order ethanol > butanol > hexanol, whereas longer chain n-alcohols inhibited MII formation with decanol > octanol. The magnitude of the stimulatory effects was greater in a more highly unsaturated phospholipid. Alcohols, which enhanced MII formation also increased phospholipid acyl chain packing free volume, while those that decreased this bilayer property inhibited MII formation. An apparent discontinuity in the effect of these alcohols results when their potency is calculated in terms of the total aqueous alcohol concentration. In sharp contrast, a continuous variation in their behavior is observed, when their potency is calculated in terms of the amount of alcohol partitioned in the membrane. Our findings strongly support a lipid-mediated mechanism of action for alcohols on rhodopsin and, by analogy, for other G protein-coupled receptors.

Visual transduction is one of the best characterized G protein--coupled signalling systems. In addition, about 50% of the disk membrane phospholipid acyl chains are 22:6n-3, making this system ideal for determining the role of polyunsaturation in modulating membrane-signalling systems. The extent of formation of metarhodopsin II (MII), the G protein--activating photointermediate of rhodopsin, was studied in phospholipid vesicles composed of a variety of phosphatidylcholines, differing in their acyl chain composition at the sn-2 position. The amount of MII formed increased progressively with the level of acyl chain unsaturation at the sn-2 position. The effect of added cholesterol was to reduce the amount of MII formed. The acyl chain packing free volume of the rhodopsin containing lipid vesicles was characterized by a fractional volume parameter fv derived from measurements of the time-resolved fluorescence anisotropy decay of the hydrophobic membrane probe 1,6-diphenyl-1,3,5-hexatriene. The relationship among sn-2 acyl chain unsaturation, cholesterol content, and MII formation is explained on the basis of variation in fv with bilayer lipid composition and a novel model for the packing of phospholipids containing polyenoic acyl chains, such as 22:6n-3.

A 71 year old man with newly diagnosed acute myelomonocytic leukaemia developed a soft tissue infection of his foot during his first course of chemotherapy. Scedosporium apiospermum was isolated from the lesion, which resolved rapidly on treatment with intravenous amphotericin B despite being resistant in vitro to this agent. This observation suggests that sensitivity testing of S apiospermum should be interpreted with caution and that clinical response may be a better indicator of outcome.

The role of phospholipids in modulating the effect of ethanol on membrane receptor activation was investigated by studying the extent of metarhodopsin II (MII) formation in vesicles formed POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) and PDPC (1-palmitoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine) and in native rod outer segment disk membranes as a function of ethanol concentration. The equilibrium concentration of MII, the G protein-activating form of photoactivated rhodopsin, was found to increase as a function of ethanol concentration in all three bilayers. Phospholipid composition had a marked effect on ethanol potency, with the presence of polyunsaturated phospholipid acyl chains increasing ethanol potency by 40%. The effects of ethanol on lipid acyl chain packing in POPC and PDPC were investigated using frequency domain anisotropy decay measurements of the fluorescent membrane probe 1,6-diphenyl-1,3,5-hexatriene. Enhanced formation of MII due to the presence of ethanol was correlated with the effects of ethanol on acyl chain packing properties. These findings support a phospholipid-mediated mechanism for the action of ethanol in modulating integral membrane receptor conformation.

We reviewed the long-term outcome of thirty-six patients who had a myelomeningocele at the sacral level and whose average age was twenty-nine years (range, nineteen to fifty-one years). The patients were followed at our institution for an average of ten years (range, one to thirty-three years); however, the medical records from birth on were available for all of the patients. Instead of the expected outcome that function had been maintained in this group of patients, we found a decline in the ability to walk of eleven of the thirty-five patients who had been community ambulators initially. At the time of the most recent follow-up examination, five had become household ambulators, two were non-functional ambulators, and four were non-ambulators. The one patient who initially had been a household ambulator was a non-ambulator at the time of the most recent follow-up examination. A decrease in plantar flexion was found in fourteen patients and a decrease in plantar sensation, in fifteen. Breakdown of the skin and soft-tissue infections on the plantar surface of the metatarsal heads and of the heel were seen in twenty-seven and twenty-three patients, respectively, and were related to the absence of plantar sensation. Fifteen patients had osteomyelitis involving the lower extremity. Eleven patients had had a total of fourteen amputations: five involved one toe or more, four involved one ray or more, two were Syme amputations, and three were below-the-knee amputations. By the most recent follow-up examination, thirty-three patients had had a total of 371 orthopaedic procedures. The procedures included tendinous procedures; osteotomies; soft-tissue releases, transfers, and débridements; amputations; and arthrodeses of the lower extremities or spine.

A study was performed to evaluate the effect of low-dose aspirin (75 mg/day) on platelet reactivity in patients with peripheral vascular disease. Platelet function was measured in 31 patients with advanced peripheral vascular disease requiring surgery. Shear-induced haemostasis and collagen-induced thrombus formation were used as indicators of platelet reactivity. They were measured in non-anticoagulated fresh whole blood samples ex vivo using a haemostatometer. Results were compared with those from 30 age- and sex-matched controls. Shear-induced haemostasis and collagen-induced thrombus formation were also measured in 18 of the 31 patients before the start of aspirin administration (before operation) and 1 week after surgery. Patients with advanced peripheral vascular disease were found to have increased platelet reactivity with a mean(s.e.m.) shear-induced haemostasis index of 1977(180) mmHg s compared with a control value of 3161(234) mmHg s (P < 0.001) and a mean(s.e.m.) collagen-induced thrombus formation index of 3980(460) mmHg s compared with a control value of 5350(420) mmHg s (P = 0.02). Perioperative low-dose aspirin failed to inhibit platelet function in patients with peripheral vascular disease.

A novel heterozygous TGG-->TAG (Trp-29-->Term) substitution was detected in three members of a family with inherited type 1 protein C deficiency and recurrent venous thrombosis.

The present studies were conducted to evaluate the cholesterolemic effects of whole-food diets high in stearic acid. In study no. 1, normocholesterolemic young men were fed diets high in stearic acid provided by cocoa butter (CB); oleic acid provided by olive oil (OO); linoleic acid provided by soybean oil (SO); and myristic acid (and lauric acid) provided by dairy butter (B). In study no. 2, different subjects with similar baseline characteristics were fed diets high in stearic acid provided by milk chocolate (C), CB, CB+B (4:1, MIX), and myristic (and lauric) acid provided by B. Both studies used a randomized, crossover, double-blind experimental design, and experimental subjects (n = 18 for study no. 1 and n = 15 for study no. 2) in each study consumed every diet for 26 days with a 1-month wash-out period between each experimental period. The diets provided 37% of calories from fat, of which 81% was provided by the test fat. Ten ounces (280 g) C was provided daily by the C diet. In study no. 1, the B diet was hypercholesterolemic, whereas the SO diet was hypocholesterolemic, compared with the other diets. The OO and SO diets were hypocholesterolemic compared with the CB diet. Low-density lipoprotein (LDL) cholesterol levels, in general, paralleled the changes in plasma total cholesterol levels. SO significantly decreased apolipoprotein (apo) B levels compared with the other diets. Plasma very-low density lipoprotein (VLDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and apo A-I levels were unaffected by the experimental diets.(ABSTRACT TRUNCATED AT 250 WORDS)

The yellow color of atherosclerotic plaque is due to the presence of carotenoids, which absorb light between 430-530 nm and account for the preferential ablation of plaque by the pulsed dye laser operating at 480 nm. This study was designed to examine tissue uptake of beta-carotene and the effect of uptake on arterial plaque ablation. Forty-two atherosclerotic NZW rabbits were given intravenous beta-carotene at a dose of 40 mg/kg, twice weekly and killed between 1 hour and 28 days after the initial injection. beta-carotene was not detected in control specimens but was significantly greater in plaque than in normal wall at all time points following beta-carotene injection (P < 0.04 Mann Whitney U test). The ablation threshold was significantly lower in beta-carotene treated plaque than in untreated plaque or normal arterial wall (P < 0.01, Fisher's exact test). In this model beta-carotene is preferentially taken up into arterial plaque, resulting in increased absorption of laser radiation at 480 nm and enhanced tissue ablation.

This study, conducted in 1991, examined the time requirements and costs of obtaining 24-hour dietary recalls via telephone interviews using the University of Minnesota's microcomputer Nutrient Data System to conduct the interviews and compute the nutrient composition of the diets. The subjects were 156 hypercholesterolemic children (aged 4-10 years) and 102 hypercholesterolemic adults (aged 21-65 years), who were participating in ongoing cholesterol education programs. A total of 391 recalls were completed with the children and 278 with the adults. For each completed interview, 3.5 and 2.8 attempts were required, respectively. Evenings were the most productive time for completing interviews. All tasks associated with completing the interviews (attempts to call, interviews per se, and postinterview procedures) required an average of 39.7 and 35.5 minutes per completed interview with the children and adults, respectively. About half of these total times were actually devoted to conducting the interview. The costs per completed interview were $9.22 for the children versus $6.99 for the adults. This difference reflects the greater number of attempts required to reach the children, the longer duration of their interviews, and the higher intrastate toll rates for calls to them as compared with the interstate rates for calls to the adults.

The superfamily of membrane-bound receptors, which function in signal transduction by activating a guanine nucleotide binding protein or G-protein in response to agonist binding, shares a number of structural and mechanistic properties. Among these similarities is downregulation of functional activity via receptor phosphorylation. In this study, the effects of intermediate levels of phosphorylation (greater than or equal to 4 added phosphates per receptor molecule) on receptor conformational equilibria are examined by comparing the photochemical properties of phosphorylated and unphosphorylated rhodopsins which were incorporated separately into 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine vesicles. Postflash spectra reflecting the contributions of metarhodopsins I, II, and III (meta I, meta II, and meta III) were obtained from these samples. Deconvolution of appropriate difference spectra allowed a determination of the concentration of the photointermediates of interest. Meta II is the form of photolyzed rhodopsin which binds and activates the visual G-protein (Gt); thus, its relative abundance at equilibrium and temporal stability are important parameters in determining the efficiency of visual signal transduction. The effects of pH and temperature on the meta I in equilibrium with meta II equilibrium constant (Keq) and the rate of decay of meta II to meta III were examined for the reconstituted phosphorylated and unphosphorylated rhodopsin samples. Keq was essentially unaffected by phosphorylation when measured at pH 7.0 and 8.0 and 20 and 37 degrees C. The decay time (lifetime) of meta II----meta III had a value of approximately 4.7 min in both phosphorylated and unphosphorylated samples.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of phospholipid bilayer acyl chain packing free volume on the equilibrium concentration of the form of photolyzed rhodopsin which initiates visual signal transduction, metarhodopsin II (meta II), is examined in reconstituted systems formed from the saturated phospholipid dimyristoylphosphatidylcholine (DMPC) and in the polyunsaturated phospholipid sn-1-palmitoyl-sn-2-arachidonoylphosphatidylcholine (PAPC) with and without 30 mol% cholesterol. The extent of meta II formation is determined from both flash photolysis measurements and rapidly acquired absorbance spectra. Equilibrium and dynamic properties of the lipid bilayer are characterized by the dynamic fluorescence properties of 1,6-diphenyl-1,3,5-hexatriene (DPH). DPH orientational properties are characterized by fv, a parameter which reflects the volume available for probe reorientation in the bilayer, relative to that available in an unhindered, isotropic environment [Straume, M., & Litman, B. J. (1987) Biochemistry 26, 5121-5126]. The metarhodopsin I in equilibrium with meta II equilibrium constant, Keq has a linear relationship with fv for rhodopsin in PAPC vesicles with and without cholesterol as well as for rhodopsin in DMPC vesicles, and these two correlation lines have different slopes. The correlations between Keq and fv in PAPC and DMPC systems are compared with a similar correlation in the native rod outer segment disk membrane and one reported previously in an egg phosphatidylcholine (egg PC) system [Mitchell, D. C., Straume, M., Miller, J. L., & Litman, B. J. (1990) Biochemistry 29, 9143-9149].(ABSTRACT TRUNCATED AT 250 WORDS)

In January 1991 the winter meeting of the Surgical Research Society was held at St. Bartholomew's Hospital and the Institute of Education, London. During the meeting a symposium was held entitled 'Shedding light on lasers'. Speakers addressed the general principles of lasers, laser-tissue interactions and the applications of lasers in gastro-enterology and in vascular disease. This was followed by an open discussion of the current indications, complications and outcome, together with future possible applications for lasers in medicine.

A flashlamp-pumped pulsed dye laser operating at either 480 or 504 nm, coupled to an integral ball-tipped optical fibre, was used to recanalize occluded lower limb arteries. All channels created by the laser were augmented with balloon dilatation. We have treated 78 limbs in 71 patients; 46 limbs (59 per cent) had rest pain and 22 (48 per cent) of these had tissue loss. The median occlusion length was 18 (range 0.5-58) cm. Technical success was achieved in 58 limbs (74 per cent) with clinical success in 46 (59 per cent). Success rates fell with increasing length of occlusion. Two patients died in the perioperative period. A subgroup of 22 patients with marked discrete arterial calcification had a lower technical success rate than the subgroup without calcification (50 per cent versus 84 per cent, P less than 0.01). Both subgroups displayed a similar pattern of reclosure during follow-up. The cumulative patency rate after technical success was 67 per cent at 6 months and 45 per cent at 12 months. Forty-six (59 per cent) limbs avoided bypass surgery or amputation. Laser-assisted angioplasty may offer an alternative to femoropopliteal bypass, although the former procedure is not as durable.

Absorption of a photon by the visual pigment rhodopsin leads to the formation of an activated conformational state, denoted rho*, which is capable of activating the visual G-protein, Gt. The bleaching of rhodopsin can be resolved into a series of spectrally distinct photointermediates. Previous studies suggest that the photointermediate metarhodopsin II (meta II, lambda max of 380 nm) corresponds to the physiologically active form rho*. In the studies reported herein, spectral and enzymological data were analyzed and compared so as to evaluate the temporal correspondence between meta II and rho*. This information was obtained by direct observation of the meta II and rho* decay times in parallel experiments utilizing identical preparations of urea-stripped, bovine retinal rod outer segment disk membranes at pH 8.0, 20 degrees C. Postflash spectra were deconvolved to resolve the meta II absorbance at 380 nm, and a decay time for the loss of meta II of 8.2 min (SD = 0.5 min) was obtained from fitting these data to a single-exponential decay process. The diminishing ability of bleached rhodopsin to activate Gt was measured by monitoring the level of catalyzed exchange of Gt-bound GDP for a nonhydrolyzable GTP analogue. Analysis of the decrease in the initial velocity of nucleotide exchange, measured at various postflash incubation times, yielded a rho* decay time of 7.7 min (SD = 0.5 min) when analyzed as a single-exponential process. The similarity of these decay times provides direct evidence that meta II and rho* are present over the same time regime, and further supports the equivalence of these two forms of photoactivated rhodopsin.(ABSTRACT TRUNCATED AT 250 WORDS)

Sixty-five patients with suspected deep venous thrombosis (DVT) in 68 limbs were entered consecutively into a study to compare venography with duplex ultrasonography scanning. Both tests were performed on 64 limbs, venography being contraindicated in four. Overall, duplex scanning correctly identified 86 per cent of DVTs diagnosed on venography and correctly excluded 80 per cent with negative venograms. Nearly all errors arose in the diagnosis of calf DVT. In the femoral vein duplex scanning had a specificity of 100 per cent and a sensitivity of 95 per cent. In addition, duplex scanning provided data on the limb not undergoing venography. Of 55 limbs that underwent bilateral duplex scanning, five had thrombus in the femoropopliteal segment and a negative contralateral venogram. In addition, three Baker's cysts were diagnosed. Duplex scanning can be used in patients in whom venography is contraindicated and may also provide information about the contralateral limb. We regard femoropopliteal duplex scanning as sufficiently accurate that treatment can be initiated on the basis of the scan. Duplex scanning should replace venography as the standard method of diagnosing femoropopliteal DVT; radiographic studies should now be required only when the scan result is in doubt.

The photochemical intermediate metarhodopsin II (meta II; lambda max = 380 nm) is generally identified with rho*, the conformation of photolyzed rhodopsin which binds and activates the visual G-protein, Gt [Emeis, D., & Hoffman, K.P. (1981) FEBS Lett. 136, 201-207]. Purified bovine rhodopsin was incorporated into vesicles consisting of dimyristoylphosphatidylcholine (DMPC), and the rapid formation of a photochemical intermediate absorbing maximally at 380 nm was quantified via both flash photolysis and equilibrium spectral measurements. Kinetic and equilibrium spectral measurements performed above the Tm of DMPC showed that Gt, in the absence of GTP, enhances the production of the 380-nm-absorbing species while reducing the concentration of the 478-nm-absorbing species, metarhodopsin I (meta I), in a manner similar to that observed in the native rod outer segment disk membrane. This Gt-induced shift in the equilibrium concentration of photointermediates indicated that the species with an absorbance maximum at 380 nm was meta II. The presence of rho* in the DMPC bilayer was established via measurements of photolysis-induced exchange of tritiated GMPPNP, a nonhydrolyzable analogue of GTP, on Gt. Above Tm, the metarhodopsin equilibrium is strongly shifted toward meta I relative to the native rod outer segment disk membrane; however, at 37 degrees C, 40% of the photointermediates are in the form of meta II. The formation of meta II above Tm is slowed by a factor of ca. 2 relative to the disk membrane. Below Tm, the equilibrium is shifted still further toward meta I, and meta II forms ca. 7 times slower than in the disk membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of lipid ordering on the kinetics and extent of metarhodopsin II (meta II) formation was evaluated in bovine rhodopsin which had been reconstituted into phosphatidylcholine vesicles containing 0, 15, and 30 mol% cholesterol. The rate of establishment of the dynamic equilibrium between metarhodopsin I (meta I) and the two kinetically distinguished forms of meta II in the branched meta II model [meta IIfast and meta IIslow; Straume, M., Mitchell, D. C., Miller, J. L., & Litman, B. J. (1990) Biochemistry (preceding paper in this issue)] is derived from kinetic measurements of rhodopsin photolysis in these vesicle systems at several temperatures. Values of the meta I in equilibrium with meta IItotal equilibrium constant, Keq, are calculated from the derived model-dependent rate constants, and are shown to be equivalent to those derived from rapidly acquired absorbance spectra. The presence of 30 mol% cholesterol reduces Keq by approximately 50% between 10 and 37 degrees C. Analysis of the model-dependent parameters in terms of delta H and delta S reveals that cholesterol raises the free energy of meta IIslow, relative to meta I, by increasing delta H whereas it raises the relative free energy of meta IIfast by making delta S meta IIfast relative to meta I less positive. The reduction in Keq by both temperature and cholesterol is found to be directly correlated with a parameter that reflects the free volume available for molecular motion in the hydrophobic core of the bilayer [Straume, M., & Litman, B. J. (1988) Biochemistry 27, 7723-7733].(ABSTRACT TRUNCATED AT 250 WORDS)

Flash photolysis experiments designed to monitor the establishment of the metarhodopsin I to metarhodopsin II equilibrium are interpreted according to a branched model in which two spectrally indistinguishable but kinetically distinguishable forms of metarhodopsin II are postulated to exist in equilibrium with a common pool of metarhodopsin I. This interpretation arises from the consistent requirement for at least three exponentials for a valid description of the observed growth of absorbance at 380 nm following bleaching of bovine rhodopsin in rod outer segment disk membranes. Analysis of the 380-nm transient absorbance data permitted direct determination of the five physically interpretable individual rate constants of the model. This analysis represents a more explicit interpretation of kinetic data than that employed in earlier experiments of this kind, which involved estimating only apparent rates and apparent amplitudes of discrete multiexponential functions. The 380-nm absorbance contributions of all relevant species contributing to the observed dynamic absorbance change were accounted for simultaneously during nonlinear least-squares estimation of the model rate parameters. Analysis of deconvoluted equilibrium spectra acquired from samples identical with those used in the kinetics experiments confirmed the metarhodopsin I-metarhodopsin II equilibrium constants, Keq, derived from the dynamic analyses. It is shown that Keq varies from 1.28 at 10 degrees C to 7.3 at 37 degrees C and that approximately 90% of the metarhodopsin II present is in the form of metarhodopsin IIslow over the temperature range 10-37 degrees C. A physical interpretation of this decay model is discussed in the context of a distribution of metarhodopsin II structural and energetic states.

We have reported previously the isolation and partial characterization of a 215-kilodalton (Kd) phosphomannosyl binding protein from bovine liver membranes [3,9]. In the present studies evidence is presented that the binding protein is an aggregate. Four N-terminal amino acids were detected, and the complex could be dissociated into subunits. Bovine liver membranes were extracted with the detergent, Zwittergent, in the presence of protease inhibitors. The extract was subjected to affinity chromatography on phosphomannan-Sepharose 4B, and proteins with apparent Mr values of 215 and 57 Kd were eluted with mannose 6-phosphate. As reported previously, extraction with Triton X-100 yielded only the higher molecular weight material. When the binding protein was incubated at 4 degrees C in the presence of Zwittergent TM 3-14 the 215-Kd form slowly dissociated into smaller subunits; after two months, the major species had an apparent Mr of 57 Kd. The subunits derived from the binding protein were recognized by antiserum raised against purified binding protein. Dissociation of the binding protein by Zwittergent was enhanced by incubation at 37 degrees C, the presence of dithiothreitol, and low pH values. The subunit mixture enriched in the 57-Kd subunit had a lowered ability to bind ligands containing the phosphomannosyl recognition marker. Binding was partially restored (greater than 48% of the initial value) when dissociated receptor was back exchanged with Triton X-100.

A study was made of thrice weekly haemodialysis of 3-3 1/2 hours' duration using a large surface area dialyser in patients with end-stage renal failure. Body water, potassium, and blood pressure control were satisfactory and comparable with the more widely used long dialysis schedules (6-9 hours thrice weekly). Patient rehabilitation was improved overall and the regimen enabled the dialysis unit to treat more patients despite a reduction in technical and nursing staff. The technique proved inadequate, however, in two patients with an intercurrent infection, and more intensive dialysis in recommended in such cases.

Dislocation of the talonavicular joint is rare, caused by severe abduction or adduction of the forefoot. Proper reduction is necessary to avoid equinovarus deformity, ankylosis, or degenerative arthritis. A case of talonavicular dislocation with fracture of the head of the talus in a 52-year old woman is reported, with delayed treatment by open reduction using Kirschner wires and casting for 7 weeks. This patient is successfully employed as a waitress 2 years postinjury.

A 17-year-old girl had a multicentric giant cell tumor originating in the sphenoid and sella turcica that was observed for 23 years. During the first 12 years, the same lesion also appeared in the right proximal tibia and left distal radius. Curettage of the tibial lesion and packing with processed bovine bone were followed by a chronic osteomyelitis with continued intermittent wound drainage. Curettage of the radial lesion and packing it initially with autogenous iliac bone graft and subsequently with methylmethacrylate bone cement were followed by local recurrences. The radial lesion eventually was eradicated by a segmental resection of the distal radius. The resulting bony defect was bridged with a bicortical autogenous iliac graft and stabilized with a bone plate to produce a painless solid wrist fusion. No further tumor recurrence has been noted for the past two years.

One hundred consecutive limbs presenting with primary varicose veins to a surgical outpatient clinic were assessed clinically and by Doppler ultrasound. By this means the incidence of sapheno-femoral and sapheno-popliteal incompetence was established and the relative role of these two systems in the development of varicosities determined.

In the 16 year period 1965-81, 12 patients with head and neck chemodectomas received radiotherapy. In only 1 patient did the tumour fail to respond, due to metastases, and 9 showed complete resolution of the tumour. As this form of treatment is associated with few complications, we conclude that it is the treatment of choice in those patients who are unfit for surgery and those whose tumours are technically unresectable.

Seventeen myelodysplastic patients with progressive extremity spasticity and scoliosis underwent radiological evaluation and surgical treatment. All but one were under 18 years of age at the time of surgical treatment. Duration of the clinical presentation ranged from 1 1/2 to 7 years. Metrizamide was instilled into the subarachnoid space in 12 patients, the lateral ventricle in two, and the hydromyelic cavity in three. Sequential computerized tomography scanning after intrathecal instillation of the contrast material clearly demonstrated hydromyelia in nine patients and compression of the brain stem in five. Posterior fossa decompression with plugging of the obex was performed in 12 patients, posterior fossa decompression alone in three, and ventriculoperitoneal (VP) shunting procedures in two. Of the 12 patients who underwent the obex plugging procedures, eight have shown partial or complete resolution of spasticity and an increase in motor strength with no significant postoperative complications. In contrast, posterior fossa decompression or VP shunting procedures alone have not led to a favorable neurological outcome. Hydromyelia may occur more commonly among myelodysplastic patients than previously recognized and may be treated most effectively by the obex plugging procedure.

The comparative absorption of cocoa butter (25.5% C16:0, 34.4% C18:0, 34.4% C18:1, 3.4% C18:2) and corn oil (11.4% C16:0, 2.0% C18:0, 26.4% C18:1, 60.0% C18:2) was assessed in six healthy male subjects. During 3-d experimental diet periods, free-living subjects consumed either cocoa butter or corn oil as virtually the sole source of dietary fat, provided at 40% of the total energy intake in the form of specially formulated cookies. Fat absorption was determined by quantifying total fecal lipid excretion over the 3-d period. Total fecal lipid and fecal fatty acids were determined. The percentage of fat excreted was significantly higher (p less than or equal to 0.001) when subjects consumed the cocoa butter (10.8 +/- 3.2%) vs the corn oil (3.5 +/- 1.0%) diet. These results indicate that the digestibility of cocoa butter is significantly less than corn oil and may explain, in part, previous reports of a neutral effect of dietary cocoa butter on plasma cholesterol concentrations.

Laser angioplasty with the pulsed dye laser and integral ball-tipped optical fibres was used for primary treatment of occlusive femoropopliteal vascular disease in 26 limbs of 24 patients, all of whom warranted operative intervention. 19 had "critical ischaemia", 8 had pedal ulceration, and 4 had distal gangrene. The delivery device consisted of the laser fibre loaded retrogradely into a standard 6 mm balloon angioplasty catheter, and was introduced through a common femoral artery cutdown in an attempt to recanalise femoropopliteal occlusions of a mean length of 21 cm (range 3-49). Angiographic recanalisation was achieved with a mean energy of 250 J (range 38-727 J) in 23 of the 26 limbs; in each case the channel created by the laser fibre was augmented by balloon angioplasty. Technical failure occurred in 3 patients, due to wall dissection, persistent side-branch entry, and incomplete lesion penetration, respectively. Acute occlusion within 48 h occurred in 2 diabetic patients with very poor run-off and distal gangrene, and early failure occurred in another patient due to inadequate balloon dilatation. 1 patient with segmental tibial disease below a technically successful recanalisation did not show clinical improvement. Several patients had coexisting coronary artery disease, 3 of whom died of myocardial infarction--all with patent femoropopliteal vessels. In the 21 survivors, 14 vessels remained patent at a median of 7 months' follow-up.