Long-term scintigraphic appearance of extremities following bone tumor resection and allograft reconstruction

The authors retrospectively reviewed the Tc-99m medronate scan findings in six patients who had no evidence of metastatic disease following en bloc resection of a primary osteosarcoma and subsequent limb reconstruction using allograft bone. Persistently increased radionuclide uptake was noted at the junction between the host bone and the graft, while the graft cortical bone showed persistently decreased activity. Radionuclide uptake at the periphery of the graft varied. Over time the youngest patient in the series had increasingly normal scan findings.

Sodium-dependent magnesium uptake by ferret red cells

1. Magnesium uptake can be measured in ferret red cells incubated in media containing more than 1 mM-magnesium. Uptake is substantially increased if the sodium concentration in the medium is reduced. 2. Magnesium uptake is half-maximally activated by 0.37 mM-external magnesium when the external sodium concentration is 5 mM. Increasing the external sodium concentration increases the magnesium concentration needed to activate the system. 3. Magnesium uptake is increased by reducing the external sodium concentration. Uptake is half-maximum at sodium concentrations of 17, 22 and 62 nM when the external magnesium concentrations are 2, 5 and 10 mM respectively. 4. Replacement of external sodium with choline does not affect the membrane potential of ferret red cells over a 45 min period. 5. Magnesium uptake from media containing 5 mM-sodium is inhibited by amiloride, quinidine and imipramine. It is not affected by ouabain or bumetanide. Vanadate stimulates magnesium uptake but has no effect on magnesium efflux. 6. When cell ATP content is reduced to 19 mumol (1 cell)-1 by incubating cells for 3 h with 2-deoxyglucose, magnesium uptake falls by 50% in the presence of 5 mM-sodium and is completely abolished in the presence of 145 mM-sodium. Some of the inhibition may be due to the increase in intracellular ionized magnesium concentration ([Mg2+]i) from 0.7 to 1.0 mM which occurs under these conditions. 7. Magnesium uptake can be driven against a substantial electrochemical gradient if the external sodium concentration is reduced sufficiently. 8. These findings are discussed in terms of several possible models for magnesium transport. It is concluded that the majority of magnesium uptake observed in low-sodium media is via sodium-magnesium antiport. A small portion of uptake is through a parallel leak pathway. It is believed that the antiport is responsible for maintaining [Mg2+]i below electrochemical equilibrium in these cells at physiological external sodium concentration. Thus in ferret red cells the direction of magnesium transport can be reversed by reversing the sodium gradient.

Rapid DNA sequencing by horizontal ultrathin gel electrophoresis

A horizontal polyacrylamide gel electrophoresis apparatus has been developed that decreases the time required to separate the DNA fragments produced in enzymatic sequencing reactions. The configuration of this apparatus and the use of circulating coolant directly under the glass plates result in heat exchange that is approximately nine times more efficient than passive thermal transfer methods commonly used. Bubble-free gels as thin as 25 microns can be routinely cast on this device. The application to these ultrathin gels of electric fields up to 250 volts/cm permits the rapid separation of multiple DNA sequencing reactions in parallel. When used in conjunction with 32P-based autoradiography, the DNA bands appear substantially sharper than those obtained in conventional electrophoresis. This increased sharpness permits shorter autoradiographic exposure times and longer sequence reads.

Bst DNA polymerase permits rapid sequence analysis from nanogram amounts of template

A simple, rapid method is presented for the enzymatic sequence analysis of nanogram amounts of single-stranded or double-stranded DNA. This approach employs the thermostable DNA polymerase from Bacillus sterothermophilus and exploits its ability to efficiently extend all of the template-primer complex, even at low substrate concentrations. The procedure requires few pipetting steps, no preannealing step and very short reaction time. This method can significantly reduce the cost associated with DNA polymerase and the amount of template and time required to perform the enzymatic sequencing reactions. As little as a 10-ng aliquot of such sequencing reactions can be analyzed on a fluorescence-based capillary gel electrophoresis instrument recently developed in our laboratory. This highly sensitive detection, in conjunction with the ability to efficiently sequence nanogram amounts of template, strongly suggests the feasibility of direct DNA sequencing of single bacteriophage M13 plaques without prior amplification.

Application of a new nuclear scintigraphy camera to evaluate flow and mechanical pumping of artificial hearts

To assist in the development of an artificial blood pump, The Milwaukee Heart (MH-1), a new nuclear scintigraphy camera was used to study the wash-in and wash-out patterns of the MH-1. These studies indicate the MH-1 has an ejection fraction of 59.3%, with a stroke volume of 72 +/- 3 ml, and an afterload of 130 mmHg. Flow through the device is highly uniform, with no areas of stagnation. Regional ejection fraction images demonstrate homogeneous ejection from apex to base. The ability to scan through the first pass images allows study of wash-in, mixing, and wash-out of the tracer. In conclusion, this technique may provide a new approach to evaluating artificial heart pumps.

Determination of monocyclic and polycyclic aromatic hydrocarbons in fish tissue

An analytical method is presented in which fish tissue is analyzed for neutral monocyclic and polycyclic aromatic hydrocarbons (AHs) and aromatic sulfur heterocycles (ASHs) by capillary column gas chromatography (CGC) with photoionization detection. The sample enrichment procedure includes saponification with aqueous KOH, acidification of the digestates, and extraction of the aromatic compounds into cyclopentane-dichloromethane. Adsorption chromatography on tandem segments of potassium silicate and silica gel removes 99% of the coextracted lipid. Final enrichment by gel permeation chromatography eliminates residual biogenic material and potentially interfering alkanes. Relatively volatile monoaromatics are included among the analytes by virtue of the efficiency of the complementary enrichment steps, the use of small quantities of only low-boiling solvents, and the selectivity of the detector. Most targeted compounds (AHs ranging in size from C3-alkylbenzenes through benzo[g,h,l]perylene and ASHs within the same size range) can be determined in 5 g (wet weight) samples of fish tissue at concentrations as low as 20 ng/g. Comparisons are made of recoveries of selected AHs under ordinary and gold fluorescent lighting conditions.

Incidence and management of secondary malignancies in patients with retinoblastoma and Ewing's sarcoma

Childhood cancer survivors at highest risk of developing a secondary malignancy are those with hereditary retinoblastoma. The majority of such secondary cancers will be sarcomas, most commonly of bone. One-third of these occur outside a typical radiation field, commonly in an extremity. Bone sarcoma is also the most commonly reported secondary cancer to develop among survivors of Ewing's sarcoma. In this group, radiation doses greater than 60 Gy as well as alkylating agent chemotherapy have been identified as contributors to the increased risk. The prognosis for patients with a secondary sarcoma has been poor, with few cures reported to date. However, an aggressive, combined modality approach, including radical resection, postoperative radiation, and adjuvant chemotherapy, may improve the survival rate.

Allergic conjunctivitis: a survey of new antihistamines

The objective of this study was to determine the therapeutic value of a wide variety of H1 antihistamines for potential ophthalmic use by performing ocular toxicity and efficacy tests in rabbits and humans. Fourteen antihistamines were formulated into ophthalmic preparations and were screened in the rabbit model; of these, thirteen were preliminary evaluated for toxicity and efficacy in humans. Based on comfort and efficacy, four (pheniramine, chlorpheniramine, dexbrompheniramine and pyrilamine) were selected for more extensive dose response and efficacy testing. 0.3% chlorpheniramine, dexbrompheniramine, pyrilamine and pheniramine significantly reduced histamine-induced itching (p less than or equal to 0.01 for each drug) and conjunctival injection (p less than or equal to 0.02 for each drug), when compared to contralateral eyes receiving PBS. When compared to 0.3% pheniramine in the fellow eye (mean difference score = 0.79 +/- 0.21), 0.3% chlorpheniramine (1.5 +/- 0.22; p = 0.04) and 0.3% dexbrompheniramine (1.71 +/- 0.18; p = 0.01) were superior in decreasing histamine-induced itching. Dose-response curves demonstrated that 0.4% and 0.5% pheniramine were statistically superior to 0.3% in relieving itching and redness. Compared to 0.3% pheniramine, 0.1% and 0.2% chlorpheniramine and 0.2% pyrilamine were statistically superior in inhibiting redness and itching. The results of this study suggest that 0.1%, 0.2% and 0.3% chlorpheniramine, 0.3% dexbrompheniramine, 0.2% pyrilamine, and 0.4% and 0.5% pheniramine were effective in relieving the itching and conjunctival injection associated with topically applied histamine. These seven formulations should be considered as possible new preparations for use as ophthalmic antihistamines and may warrant further evaluation.

Magnesium transport in ferret red cells

1. Mg2+ efflux from ferret red cells into a nominally Mg2(+)-free medium is 41 +/- 2 mumol (l cell)-1 h-1. The properties of Mg2+ transport can be measured in these cells without the need for Mg2+ loading. 2. Amiloride, quinidine, imipramine and external divalent cations partially inhibit Mg2+ efflux. Maximal inhibition by these agents is about 60-70% suggesting that at least two Mg2+ transport pathways exist. 3. As external Na+ is replaced by choline or N-methyl-D-glucamine Mg2+ efflux is first stimulated, reaching a peak when external [Na+] ([Na+]o) is about 10 mM, and then inhibited. Mg2+ transport reverses direction so net Mg2+ uptake occurs when [Na+]o is reduced below 1 mM. 4. Mg2+ efflux is stimulated when 0.1 mM-EDTA is added to the medium only when [Na+]o is low. 5. Reduction of cell ATP content to about 20 mumol (l cell)-1 by treating cells with 2-deoxyglucose stimulates Mg2+ efflux measured over the 2 h period following depletion. 6. Substantial Mg2+ influx can be observed in ferret red cells when they are incubated in media containing 10 mM-Mg2+. Influx is stimulated by reducing [Na+]o to 10 mM. Further reduction of [Na+]o to below 1 mM reduces Mg2+ uptake. A component of uptake is inhibited by external Co2+. 7. Na(+)-Mg2+ antiport may account for a substantial component of Mg2+ transport in ferret red cells. The direction of transport can be reversed by sufficiently lowering [Na+]o or by increasing external [Mg2+]. Analysis of the conditions at which transport reverses direction suggests transport with a stoichiometry of 1 Na+:1 Mg2+. Antiport with this stoichiometry would also explain maintenance of the physiological level of intracellular ionized Mg2+ in these cells.

Activation of factor V during intrinsic and extrinsic coagulation. Inhibition by heparin, hirudin and D-Phe-Pro-Arg-Ch2Cl

The validity of the hypothesis that Factor Xa activates Factor V in heparinized plasma was examined by establishing the temporal relationships between Factor V proteolysis and prothrombin consumption in plasma. Factor V was cleaved into Factor Va heavy chain (approx. 110 kDa) and an intermediate (approx. 230 kDa) 30 s after CaCl2 was added to contact-activated plasma (CAP). The larger fragment was converted into Factor V activation peptide (approx. 150 kDa) and Factor Va light chain (approx. 80 kDa) 15 s later. Heparin (approx. 0.05 microM) delayed Factor V proteolysis in CAP by at least 30 s. On supplementing CAP with 1 nM-Factor Xa or 1 nM-thrombin, Factor V was activated 15 s later. Heparin prolonged by 15 s and 45 s the time required to demonstrate Factor V activation in CAP supplemented with Factor Xa and thrombin respectively. Factor V was activated 20 s after tissue factor and CaCl2 were added to plasma, both in the absence and in the presence of approx. 0.05 microM-heparin. In contrast, hirudin and D-Phe-Pro-Arg-CH2Cl (two thrombin inhibitors more effective than heparin) delayed Factor V activation in this plasma by at least 30 s. The fragments of Factor V obtained in heparinized CAP suggest thrombin escapes inhibition and contributes to Factor V activation in that plasma. Production of Factor Va heavy chain and the 230 kDa Factor V fragment invariably preceded efficient prothrombin activation. These observations suggest that heparin, hirudin and D-Phe-Pro-Arg-CH2Cl delay Factor V activation by inhibiting thrombin. The availability of Factor Xa markedly moderates the ability of heparin to inhibit Factor V activation.

Inhibition of factor X and factor V activation by dermatan sulfate and a pentasaccharide with high affinity for antithrombin III in human plasma

There is evidence that by catalyzing thrombin inhibition, several glycosaminoglycans can inhibit the thrombin-mediated amplification reactions of coagulation and thereby delay prothrombin activation. The two amplification reactions can apparently be catalysed by endogenously generated factor Xa and thrombin. This study provides evidence which suggests that on a molar basis, an agent which can only catalyse thrombin inhibition is approximately 10 times more effective than an agent which can only catalyse factor Xa inhibition in their ability to inhibit intrinsic prothrombin activation. We determined the concentrations of each of heparin, dermatan sulfate and a pentasaccharide with high affinity for antithrombin III, to delay intrinsic prothrombin activation for at least 15s. Heparin catalyses both thrombin and factor Xa inhibition; dermatan sulfate catalyses only thrombin inhibition, while the pentasaccharide only catalyses factor Xa inhibition. Efficient prothrombin activation, which coincided with both factor X activation and factor V proteolysis, was first observed 45s after CaC12 was added to contact-activated plasma. Heparin (approximately 0.1 microM) prolonged by at least 30 s the time required for the activation of the three clotting factors to begin. The minimum concentrations of the pentasaccharide and dermatan sulfate to delay the activation of prothrombin, factors X and V were approximately 50 microM and approximately 5 microM, respectively. Thus, each anticoagulant could inhibit intrinsic prothrombin activation only when it inhibited activation of both factors X and V. A combination of approximately 5 microM pentasaccharide and approximately 0.05 microM dermatan sulfate similarly delayed the activation of all three clotting factors. Thus, while catalysis of thrombin inhibition is a more effective pathway than catalysis of factor Xa inhibition for delaying prothrombin activation, the simultaneous catalysis of thrombin and factor Xa inhibition can synergistically improve the ability of a sulfated polysaccharide to delay prothrombin activation.

Developmental regulation of expression of the malate synthase gene in transgenic plants

The cucumber malate synthase (MS) gene, including 1856 bp of 5' non-transcribed sequence, has been transferred into Petunia (Mitchell) and Nicotiana plumbaginifolia plants using an Agrobacterium binary vector. The transferred gene is found in variable copy number in different transformants, and is stably transmitted in each case as a single Mendelian character. Transgene mRNA accumulates in the seedling during the first three days of germination, then declines in amount as the cotyledons emerge from the seed. The decline is more pronounced in light-grown seedlings than in dark-grown seedlings. Expression of the MS transgene is also detected at a low level in petals of transformed Petunia plants. In these respects the pattern of MS gene expression is similar in cucumber and in transformed plants, showing that the transferred DNA fragment contains a functional MS gene. A 1076 bp fragment of 5' sequence was linked to the beta-glucuronidase reporter gene and transferred into Nicotiana, where it was shown to direct temporal and spatial patterns of expression similar to that of the complete MS gene. However, histochemical localisation of beta-glucuronidase activity demonstrated that the chimaeric gene is expressed not only in cotyledons of transgenic plants, but also in endosperm and some hypocotyl cells during early germination. The relevance of these findings to the control of malate synthase gene expression is discussed.

High speed DNA sequencing by capillary electrophoresis

A major challenge of the Human Genome Initiative is the development of a rapid, accurate, and efficient DNA sequencing technology. A major limitation of current technology is the relatively long time required to perform the gel electrophoretic separations of DNA fragments produced in the sequencing reactions. We demonstrate here that it is possible to increase the speed of sequence analysis by over an order of magnitude by performing the electrophoresis and detection in ultra thin capillary gels. An instrument which utilizes these high speed separations to simultaneously analyze many samples will constitute a second generation automated DNA sequencer suitable for large-scale sequence analysis.

An automated instrument for the performance of enzymatic DNA sequencing reactions

An instrument has been developed for the automation of enzymatic DNA sequencing reactions. Up to 96 DNA templates contained in a microtiter plate can be processed for either radioactive or fluorescence-based sequence analysis in a three-hour period. The quality of the resultant data is comparable to that obtained manually. The system is simple, flexible and is readily adapted to the use of new polymerases or modified experimental protocols.

High-speed separations of DNA sequencing reactions by capillary electrophoresis

Fluorescently labeled DNA fragments generated in enzymatic sequencing reactions are rapidly separated by capillary gel electrophoresis and detected at attomole levels within the gel-filled capillary. The application of this technology to automated DNA sequence analysis may permit the development of a second generation automated sequencer capable of efficient and cost-effective sequence analysis on the genomic scale.

Effects of Vasocon-A in the allergen challenge model of acute allergic conjunctivitis

The ophthalmic combination product of 0.05% naphazoline hydrochloride and 0.5% antazoline phosphate (Vasocon-A) was evaluated as an antiallergic agent in 100 subjects with a known allergic history to cat dander, ragweed, or bluegrass pollen. Three independent study sites were used. The allergen challenge model of acute allergic conjunctivitis was selected to assess the agent as it provided a standardized and precise way to measure drug effectiveness for this indication. In a double-masked randomized fashion, the subjects were assigned to one of three groups that received one drop of Vasocon-A in one eye and one drop of either 0.05% naphazoline (group 1), 0.5% antazoline (group 2), or placebo (group 3) in the contralateral eye. After 10 minutes, the dose of allergen shown to elicit a 2+ redness and itching reaction was instilled bilaterally. Signs and symptoms of allergic conjunctivitis were evaluated after 3, 5, and 10 minutes. Subjects were then rechallenged 2 hours after drug administration to assess the duration of action of the agents. Vasocon-A was found to significantly inhibit all five major signs and symptoms of allergic conjunctivitis: itching, redness, chemosis, lid swelling, and tearing, for more than 85% of the comparisons when compared over time with placebo, naphazoline alone, or antazoline alone. The results of this study indicate that the combination of naphazoline and antazoline was more effective in inhibiting redness than naphazoline and more effective in inhibiting itching than antazoline. These findings support the use of such a combination for the treatment of allergic conjunctivitis.

Solidification studies using a confocal optical signal processor

The development of a confocal optical processing system and its application to a solidifying metal model are reported. This system has been used to acquire image format data from which quantitative temperature and concentration profiles have been measured. Strong agreement is shown to exist between experimental results obtained in this manner and numerical simulations.

Conjunctival allergen challenge. A clinical approach to studying allergic conjunctivitis

To evaluate antiallergic agents, we conducted five allergen challenge studies of increasing refinement. The final study design that evolved included two baseline visits, when skin test-positive subjects were administered a bilateral ocular allergen challenge. At the first visit, the threshold dose of reactivity was determined by increasing allergen doses at 10-minute intervals. At the second baseline visit, 3 days later, the responsive subjects were challenged with the final, highest dose used on visit 1 to assure that the allergic reaction was reproducible and not a cumulative effect of multiple allergen doses. The responsive subjects then returned 3 days later for the drug efficacy evaluation. After a slit-lamp examination, subjects were pretreated with the test drug in one eye and the placebo in the fellow eye in a randomized, double-masked fashion. After 10 minutes, subjects were challenged bilaterally with the allergen dose identified on the previous visits. Postchallenge evaluations of hyperemia, itching, chemosis, eyelid swelling, and tearing were performed at 3, 10, and 20 minutes. Subjects were rechallenged 4 hours after drug administration to assess duration of action. Slit-lamp examinations were again performed at the same intervals as after the initial challenge. A total of 396 subjects were given a baseline allergen challenge; 83.6% responded with a moderate (2+) ocular allergic reaction. Of the 266 given a second baseline challenge, 87.2% responded positively again, suggesting that ocular challenge was highly correlated with skin reactivity and reproducible with a second challenge. No statistically significant difference in redness and itching was found when both eyes were challenged with the same dose of allergen.(ABSTRACT TRUNCATED AT 250 WORDS)

Aggressive management of second primary tumors in survivors of hereditary retinoblastoma

Survivors of hereditary retinoblastoma are at increased risk for the development of second primary tumors, most commonly osteosarcoma. Recent molecular genetic data demonstrate that a pleiotrophic effect of the retinoblastoma gene may be responsible for the development of these sarcomas. This report describes the incidence of second nonocular malignancies among 53 infants seen at Stanford University Medical Center who have been followed a median of 11.7 years. Of these, 42 initially had bilateral disease and eleven had unilateral disease. Of 53 infants, 50 received irradiation either as part of the initial therapy or as treatment for recurrent disease. The actuarial survival for the entire group is 67% at 30 year follow-up with a median survival of 79% at 11.7 years. Eight patients developed eleven second primary tumors. All occurred in the group having hereditary retinoblastoma. Eight were within the previously irradiated field and three were at distant sites. The second tumors included seven osteosarcomas, one angiosarcoma, one rhabdomyosarcoma, one malignant fibrous histiocytoma, and one unclassifiable round blue cell tumor. The actuarial incidence of the development of a second primary malignancy was 6% at 10 years, 19% at 20 years, and 38% at 30 years. The latent period from treatment of retinoblastoma to the diagnosis of malignancy ranged from 5.2 years to 36.2 years (median 16 years). An aggressive approach with combined modality therapy including radical resection, re-irradiation and/or chemotherapy was used to treat these second primary tumors in five of eight patients. In four of the five, there was no evidence of disease at 22-72 months following treatment. In the three patients who did not receive aggressive combined treatment, there were no survivors. These data confirm the previously reported risk of developing a second primary tumor among survivors with hereditary retinoblastoma. Careful long-term follow-up for this genetically susceptible group is essential for early detection and implementation of curative therapy.

Absolute displacement measurements using modulation of the spectrum of white light in a Michelson interferometer

A technique is presented for measuring small displacements by observing the frequency of spectral modulation of white light in a Michelson interferometer. An experiment is described in which the step size of a stepper-motor-driven translation stage was measured by recording the spectrum of light output from an interferometer and performing a cross-correlation calculation with theoretical spectra. Measurements made using standard laboratory-quality optical equipment were accurate to within ~10 nm for a range of over 100 microm.

Plasma anticoagulant mechanisms of heparin, heparan sulfate, and dermatan sulfate

The relationship between two anticoagulant actions of glycosaminoglycans (GAGs), namely the catalysis of thrombin inhibition (assessed by thrombin-antithrombin-III and thrombin-heparin-cofactor-II formation) and the inhibition of prothrombin activation, was explored by comparing the effects of heparin, heparan sulfate, and dermatan sulfate on the two reactions in plasma. Heparan sulfate and dermatan sulfate were also resulfated in vitro to yield products with sulfate/carboxylate ratios similar to those of heparin. Their effects on thrombin inhibition and the activation of prothrombin were also determined. The catalytic efficiency of the five GAGs on thrombin inhibition and their inhibitory effects on prothrombin activation decreased in the following order: heparin; resulfated dermatan sulfate; resulfated heparan sulfate; heparan sulfate = dermatan sulfate. These results suggest that the catalytic efficiency of a glycosaminoglycan on thrombin inhibition translates to its inhibitory effect on prothrombin activation, since catalysis of thrombin inhibition results in the inhibition of the thrombin-dependent positive feedback reactions of coagulation which facilitate prothrombinase formation.

The effect of dietary fatty acid composition on liver retinyl ester (vitamin A ester) composition in the rat

The dependence of liver retinyl ester (vitamin A ester) composition on dietary fatty acid composition was studied in rats. Weanling male Sprague-Dawley rats were fed purified test diets containing 8% of one of 10 test triglycerides (either tributyrin, tricaproin, tricaprylin, tricaprin, trilaurin, trimyristin, tripalmitin, tristearin, triolein, trilinolein) or corn oil (a mixed triglyceride) for 23 d after an initial 1-wk stabilization period. Essential fatty acids were provided by safflower oil (8 g/kg diet). Total liver fatty acid composition showed the expected responses to dietary fatty acid intake; short-chain and medium-chain fatty acids were readily elongated to palmitate and stearate, and palmitate and stearate were readily desaturated. Consumption of oleate or linoleate (as their triglycerides) markedly enriched their concentrations in liver lipids. The proportions of palmitate were generally greater in liver retinyl esters than in total liver fatty acids, and the proportions of oleate were less. However, retinyl ester composition was significantly affected by dietary triglyceride, particularly by diets providing long-chain fatty acids. Total liver vitamin A levels were depressed in the group fed trilinolein.

Adaptability of endothelial orientation to blood flow dynamics--a morphologic analysis

Vascular endothelium has a certain specificity in its anatomical orientation. The long axis of the endothelial cell and the shingle effect of cell process overlapping is always oriented parallel to the direction of blood flow. To determine whether this specific anatomical orientation would be maintained when the direction of blood flow was altered, twenty ilio-femoral vein segments and twenty vascular patches of carotid artery and jugular vein were studied. Valvulotomised ilio-femoral vein segments (n = 20) were interposed into adjacent arteries in a non-reversed fashion (the direction blood flow is reversed to the cell process overlapping). One centimeter-square carotid artery and jugular vein patches (n = 20) were rotated 90 degrees (endothelial cell orientation is perpendicular to the direction of blood flow). Reversal of endothelial cell overlapping to complement the complete reversal of the direction of blood flow exists in the vein graft through re-endothelialisation and endothelial reorientation. The process of endothelial reversal occurred in stages (endothelial cell process retraction, interdigitation, complete reversal) and was completed within 8-16 days. In the vascular patch, endothelial re-orientation occurred in 8 days through cell re-orientation and replacement. Mitosis was not encountered in either study. This report highlights certain functions and the adaptive capability of endothelial cells to complement the direction of blood flow.

Retinoblastoma: biology, presentation, and current management

Retinoblastoma is an uncommon ocular tumor of childhood which accounts for 5% of childhood blindness. It serves as a prototype for understanding the genetics of childhood cancer. The identification of the retinoblastoma gene has provided an explanation for the differing features of hereditary and nonhereditary retinoblastoma, as well as the potential for secondary malignancies in the hereditary cases. Management decisions are based upon the potential for useful vision, and the extent of disease including whether one or both eyes are involved. As nearly all patients present with disease confined to the globe, local control is excellent and survival exceeds 85%. Goals of management are cure of the disease, preservation of vision, and early detection and treatment of secondary malignancies in the genetically susceptible group.

Automated DNA sequencing and the analysis of the human genome

The Human Genome Initiative is a complex, multifaceted, international effort to establish a massive data base of map and sequence information for humans and other organisms. The success of this initiative is dependent upon the development of new technologies for the analysis of genomes. In this paper, an overview of the Human Genome Initiative is presented, and the current status of efforts to automate large-scale DNA sequence analysis is reviewed.

Results of a prospective study evaluating the effects of mantle irradiation on pulmonary function

Thirty patients with Stages I-III Hodgkin's disease receiving mantle irradiation were prospectively evaluated prior to therapy with spirometry, lung volumes, and tests of diffusing capacity (DLCO). Follow-up examinations were performed at 3, 6, and 12 months and then yearly. Sixteen patients had Hodgkin's disease involving the mediastinum at presentation, 10 were smokers, and 16 received either preirradiation or postirradiation chemotherapy. Mantle doses ranged between 2300 cGy and 4000 cGy (mode of 3750 cGy) given at 150 cGy to 170 cGy tumor dose per day with split-course technique. Pulmonary function test results were translated to percent change from predicted values obtained from normal standards for each age, sex, race, and height. These percent changes were then analyzed as a linear function of time. Twenty patients have been tested greater than or equal to 4 years after treatment with a median time from treatment to last pulmonary function test of 8 years. Changes over time in spirometry included an early, mild decrease in both forced vital capacity (FVC) and forced expiratory volume at 1 second (FEV1), which returned to baseline by 2 years and then gradually decreased to a 10-15% deficit as compared with predicted values at 6-10 years. Additionally, there was a very slight decrease in FEV1/FVC beginning at 1 year and gradually increasing to an 8% deficit at 6-10 years. Changes over time in lung volumes included a mild nadir of total lung capacity (TLC) and functional residual capacity (FRC) at 6 months to a year, which returned to baseline at 2-4 years and then gradually dropped to a 5-10% deficit at 6-10 years. Mean DLCO for the study group was 20% below predicted values prior to treatment and dropped to a low of 30% below predicted at 6 months following treatment, then gradually returned to baseline by 4 years and showed continued improvement to an overall deficit of approximately 10% at 6-10 years. With the exception of FEV1/FVC, the changes noted in spirometry and lung volumes were of insufficient degree to be classified as abnormal. The decrease in FEV1/FVC is indicative of a significant and progressive obstructive ventilatory defect. The effects on pulmonary function tests of smoking, the presence of mediastinal involvement by Hodgkin's disease, and exposure to chemotherapy were assessed by statistical analysis. No subsets of patients demonstrated consistent evidence of a restrictive ventilatory defect expected after irradiation.(ABSTRACT TRUNCATED AT 400 WORDS)

Prospective, randomized trial of oral piroxicam in the prophylaxis of postoperative cystoid macular edema

One hundred and seventy-eight patients undergoing uncomplicated cataract extraction with posterior chamber intraocular lens insertion completed a prospective, randomized, controlled trial of oral piroxicam in the prophylaxis of postoperative cystoid macular edema (CME), with a 1-year follow up. The incidence of "visually significant" CME, the mean interval to onset following surgery, clinical severity, recurrence rate, and the time to achieve best corrected visual result were unaffected by a 17-day piroxicam course. Oral steroid CME treatment produced a rapid response, but could not be shown to change the ultimate visual results. High-performance liquid chromatography analysis of aqueous humor obtained at cataract surgery suggested that piroxicam's pharmacokinetics might be a factor in this lack of response; the large number of potential inflammatory mediators uninfluenced by cyclo-oxygenase inhibition also may implicate piroxicam pharmacodynamics.

Unfractionated heparin inhibits thrombin-catalysed amplification reactions of coagulation more efficiently than those catalysed by factor Xa

We have proposed previously that the steps in coagulation most sensitive to inhibition by heparin are the thrombin-dependent amplification reactions, and that prothrombinase is formed in heparinized plasma only after Factor Xa activates Factor VIII and Factor V. These propositions were based on the demonstration that both heparin and Phe-Pro-Arg-CH2Cl completely inhibited 125I-prothrombin activation for up to 60 s when contact-activated plasma (CAP) was replenished with Ca2+. Furthermore, the addition of thrombin to CAP before heparin or Phe-Pro-Arg-CH2Cl completely reversed their inhibitory effects. Additional support for the above hypotheses is provided in this study by demonstrating that, when the activity of thrombin is suppressed by heparin (indirectly) or by Phe-Pro-Arg-CH2Cl (directly), exogenous Factor Xa reverses the ability of these two agents to inhibit prothrombin activation. Prothrombin activation was initiated by adding Factor Xa (1 nM) or thrombin (1 or 10 nM) simultaneously with CaCl2 to CAP. In the absence of heparin or Phe-Pro-Arg-CH2Cl, prothrombin activation was seen 15 s later in either case. Heparin failed to delay, and Phe-Pro-Arg-CH2Cl delayed for 15 s, prothrombin activation in CAP supplemented with Factor Xa. In contrast, heparin and Phe-Pro-Arg-CH2Cl completely inhibited prothrombin activation for at least 45 s in CAP supplemented with 1 nM-thrombin. Heparin failed to delay prothrombin activation in CAP supplemented with 10 nM-thrombin, whereas Phe-Pro-Arg-CH2Cl completely inhibited prothrombin activation in this plasma for 45 s. These results suggest that in CAP: (1) Factor Xa can effectively activate Factor VIII and Factor V when the proteolytic activity of thrombin is suppressed; (2) heparin-antithrombin III is less able to inhibit Factor Xa than thrombin; (3) suppression of the thrombin-dependent amplification reactions is the primary anticoagulant effect of heparin.

Identification and characterization of mutations affecting sporulation in Saccharomyces cerevisiae

Mutations affecting the synthesis of the sporulation amyloglucosidase were isolated in a homothallic strain of Saccharomyces cerevisiae, SCMS7-1. Two were found, both of which were deficient in sporulation at 34 degrees. One, SL484, sporulated to 50% normal levels at 30 degrees but less than 5% at 34 degrees or 22 degrees. The other, SL641, failed to sporulate at any temperature. Both mutants were blocked before premeiotic DNA synthesis, and both complemented spo1, spo3, and spo7. Genetic analysis of the mutation in SL484 indicated linkage to TRP5 and placed the gene 10 map units from TRP5 on chromosome VII. A plasmid containing an insert which complements the mutation in SL484 fails to complement SL641. We therefore conclude that these two mutations are in separate genes and we propose to call these genes SPO17 and SPO18. These two genes are (with SPO7, SPO8, and SPO9) among the earliest identified in the sporulation pathway and may interact directly with the positive and negative regulators RME and IME.

Levocabastine. Evaluation in the histamine and compound 48/80 models of ocular allergy in humans

The efficacy of a new antihistamine, levocabastine, in alleviating the ocular allergic reactions induced by both histamine and 48/80 was evaluated in humans. Levocabastine (0.5%) was instilled in one eye of 30 volunteers, and vehicle in the contralateral eye. After 15 minutes, half of the subjects received histamine (25 mg/ml) and half, 48/80 (7.5 mg/ml). The signs and symptoms of allergy were graded clinically after 30 minutes. Compared with a buffer control, levocabastine significantly alleviated itching (P = 0.01), redness (P = 0.0156), and chemosis (P = 0.005) induced by histamine, and itching (P = 0.032) and redness (P = 0.029) induced by 48/80. The results from these pharmacologic models support the clinical use of levocabastine for the treatment of allergic conjunctivitis.

An approach to assigning in vitro potency to unfractionated and low molecular weight heparins based on the inhibition of prothrombin activation and catalysis of thrombin inhibition

Unfractionated and low molecular weight (LMW) heparins with good antithrombotic activity invariably catalyze thrombin inhibition and inhibit the appearance of thrombin activity in contact-activated plasma. Conversely, the antithrombotic efficacy of LMW heparins decreases as their ability to catalyze thrombin inhibition and to inhibit the appearance of thrombin activity in plasma decrease. The activated partial thromboplastin time (APTT) has proven a reliable test for assaying unfractionated heparin. We therefore compared 2 unfractionated and 3 LMW heparins on the basis of the minimum concentrations required to double the APTT of normal plasma and by then determined how this anticoagulant effect was achieved. The amount of unfractionated and LMW heparin which doubled the APTT was found to be equivalent to approximately 0.25 antithrombin units. This concentration of each glycosaminoglycan completely inhibited prothrombin activation for 45 s after CaCl2 was added to contact-activated plasma; accelerated thrombin inhibition by purified antithrombin III by approximately 50-fold; and accelerated thrombin inhibition equally by antithrombin III in undiluted plasma. This concentration of the three LMW heparins increased, by approximately 70-fold, the rate of factor Xa inhibition by purified antithrombin III compared to the 50-fold increase seen with the two unfractionated heparins. These results thus suggest that tests based on the inhibition of prothrombin activation and/or on the catalysis of thrombin inhibition provide a useful basis for assigning in vitro potency to both unfractionated and LMW heparins.

Conserved cysteine and histidine residues of the avian myeloblastosis virus nucleocapsid protein are essential for viral replication but are not "zinc-binding fingers"

The nucleocapsid protein from the Rous sarcoma virus has two regions of sequence with the motif Cys-Xaa-Xaa-Cys-Xaa-Xaa-Xaa-Gly-His-Xaa-Xaa-Xaa-Cys. All retrovirus nucleocapsid proteins contain one or two of these motifs, and they represent the only conserved sequences among these proteins. Sequence analysis of nucleocapsid from avian myeloblastosis virus shows that it also contains two Cys-His sequences and, in fact, differs from the Rous sarcoma nucleocapsid protein only in three residues near the carboxyl terminus. The hypothesized role of the conserved cysteines and histidines as zinc ligands was tested experimentally. No tightly bound metal ions were detected for avian myeloblastosis nucleocapsid protein, and the molar amount of zinc in virions was less by a factor of 50 than that of the nucleocapsid protein. Added Zn2+ did not significantly affect nucleocapsid binding to poly(ethenoadenylic acid) or its secondary structure, as determined from circular dichroism. Nevertheless, the conserved cysteine and histidine residues of the Rous sarcoma (Prague-C strain) nucleocapsid protein are essential for fully functional virus, as shown by the fact that single-site substitutions of five of the six conserved cysteines and either of the two histidine residues blocked viral replication.

Semi-preparative purification of recombinant human renin and prorenin

Chinese hamster ovary (CHO) cells, transfected with a vector containing cDNA coding for preprorenin, have been shown to secrete authentic prorenin into the culture supernatant. Purification of the expressed prorenin and purification of active renin, generated by solid-phase trypsin treatment of the conditioned media, have been achieved by conventional chromatographic methods. Scale-up of the initial steps of these procedures is described, including the use of radial-flow columns and automation with fast protein liquid chromatography valves and pumps. This semi-preparative scheme has allowed hundreds of milligrams of both proteins to be isolated.

Characterization of recombinant human prorenin and renin

A cell line that secretes substantial quantities of recombinant human prorenin was prepared by transfecting Chinese hamster ovary cells with a gene encoding preprorenin. The prorenin was purified to homogeneity and was found to have a single amino terminus, reflecting cleavage after a typical 23 amino acid signal sequence. The purified inactive prorenin was not a substrate for active renin and was not capable of self-activation. Prorenin could be converted to renin by addition of exogenous protease, and deglycosylation of the prorenin did not alter the sensitivity to protease activation. The enzymatic activity of deglycosylated renin was kinetically identical to that of the native protein. Multimilligram quantities of recombinant human renin and prorenin were purified, providing suitable material for studies directed toward greater understanding of the function of these proteins and for structural studies such as x-ray diffraction for use in design of renin inhibitors.

Sustained reduction of intraocular pressure in humans with the calcium channel blocker verapamil

We investigated the effect of the calcium channel blocker verapamil on intraocular pressure in human volunteers. In the initial trial, 15 subjects with untreated ocular hypertension were tested. After a baseline measurement was obtained with applanation tonometry, a 40-microliter drop of verapamil, 1.25 mg/ml, was instilled in one eye. After 30 minutes, a second reading was taken. In a subsequent trial of 12 untreated ocular hypertensive subjects, the duration of action was determined using the same dose and method of delivery. Results showed that verapamil elicited a mean +/- S.E.M. change in intraocular pressure of -3.8 +/- 0.900 mm Hg in the treated eye, and -1.6 +/- 0.400 mm Hg in the untreated eye. This reduction was statistically different in both eyes (treated eye, P = .0007; untreated eye, P = .005). This decrease in intraocular pressure remained statistically significant when compared to predrug baseline values for up to ten hours.

Pharmacologic pupillary modulation in the perioperative period

The perioperative management of the pupil is essential to the success of anterior segment surgery. A new dilating regimen was tested in 65 cases of cataract extraction and intraocular lens implantation. The alpha-adrenergic agonist, phenylephrine 2.5%, was used after pretreatment with the adrenergic beta-blocker, timolol 0.5%. This treatment successfully dilated the pupil in all but three cases, was maintained by intraoperative epinephrine infusion, and was readily reversed with intraocular acetylcholine. We conclude that this pharmacologic regimen provided a successful and easily reversible mydriasis during surgery.

Automated DNA sequencing and analysis of the human genome

In the past few years, striking advances have been made in automating DNA sequence analysis. Currently, efforts are underway to automate and improve DNA purification, mapping, and data processing procedures. The predictable advances in these technologies should soon place us in a position to sequence the entire human genome. The information derived from this project will have profound implications for basic biology and clinical medicine alike.

Deletion of lysine 13 alters the structure and function of parathyroid hormone

A peptide of unknown structure was found as a side product in a commercial preparation of the 1-34 fragment of bovine parathyroid hormone (PTH). CNBr cleavage and amino acid analysis showed that this peptide is the des-lys-13 form of 1-34 bovine PTH. The peptide thus represents a deletion mutant of PTH and structure-function studies are of interest. This peptide was a full agonist in the adenylyl cyclase bioassay for PTH, but its potency was about 5% of that found for the complete 1-34 peptide. Proton NMR studies showed that the pK values for the histidine residues in the des-lys-13 form were essentially identical to those of the intact peptide. However, pH-dependent changes in the chemical shifts for the tryptophan protons (residue 23) and several unidentified methyl group resonances were observed in the des-lys peptide. The latter are major shifts and probably represent ring-current effects; these were not seen in the intact 1-34 peptide. The results show that Lys-13 is important in the folding of the active domain of PTH, and are interpreted in the context of a previously published model for the folding of this hormone.

Characterization and partial amino acid sequence of a low molecular weight surfactant protein

Chloroform:methanol (2:1) extracts of bovine surfactant were subjected to LH-20 Sephadex chromatography in order to isolate a 6,000-dalton surfactant protein. The 6,000-dalton protein eluted in the void volume and was shown to be homogeneous by protein sequencing, although SDS gel electrophoresis revealed bands of 6, 14, and 18 kDa. The N-terminal sequence obtained was very hydrophobic, as was the amino acid composition of the 6,000-dalton protein. An antiserum raised against the low molecular weight protein fraction from TA surfactant recognized the 6,000-dalton bovine and human proteins in addition to protein bands at 14,000 and 18,000 daltons. These bands appear to be aggregates of the 6,000-dalton protein. No cross-reactivity of the 6,000-dalton protein antiserum could be demonstrated with the 35,000-dalton surfactant-associated protein. These studies strongly suggest that the 35,000- and 6,000-dalton surfactant proteins do not have a precursor-product relationship.

Use of plasma segments for estimating factor VIII activity in pools of fresh frozen plasma

This study describes a procedure for estimating the factor VIII activity of pools of fresh frozen plasma destined for fractionation into factor VIII concentrates. This information is useful for estimating overall yields. We compared the factor VIII activity of plasma packs and the attached segments shortly after the production of fresh frozen plasmas, during storage at -30 degrees C for up to 4 weeks, after shipping at -20 degrees C to the fractionation site, after storage at -30 degrees C at the fractionation site, and after cryoprecipitation. The factor VIII activity of the segments and the plasma packs were indistinguishable at all stages except after cryoprecipitation. Our results suggest that, prior to the cryoprecipitation stage, a pool of a representative number of plasma segments can be used to determine the factor VIII activity of the plasma pool to be fractionated.

Immunocytochemical localisation of phloem lectin from Cucurbita maxima using peroxidase and colloidal-gold labels

Antibodies were raised against lectin purified from the sieve-tube exudate of Cucurbita maxima. Immunocytochemistry, using peroxidase-labelled antibodies and Protein A-colloidal gold, was employed to determine the location of the lectin within the tissues and cells of C. maxima and other cucurbit species. The anti-lectin antibodies bound to P-protein aggregates in sieve elements and companion cells, predominantly in the extrafascicular phloem of C. maxima. This may reflect the low rate of translocation in these cells. Under the electron microscope, the lectin was shown to be a component of P-protein filaments and was also found in association with the sieve-tube reticulum which lines the plasmalemma. The anti-lectin antibodies reacted with sieve-tube proteins from other species of the genus Cucurbita but showed only limited reaction with other genera. We suggest that the lectin serves to anchor P-protein filaments and associated proteins to the parietal layer of sieve elements.

Proton NMR studies of the biologically active 1-34 fragment of bovine parathyroid hormone: examination of a structural model

Proton NMR spectra of the biologically active 1-34 fragment of bovine parathyroid hormone (bPTH) were studied as a function of pH over the range of pH 4 to 10, in buffer and in 6 M guanidine DC1. One of the histidine C-2 peaks titrated normally, with a pKa value of 6.8, but the other two histidines in this peptide had pKa values of 6.3. Denatured PTH showed only one histidine C-2 peak with a pKa of 6.7. An aliphatic peak identified as due to either a methionine or a glutamine residue also shifted with pH, and the pKa for this shift was 6.3. Finally, small but significant upfield shifts in the methyl and methylene resonances were observed as a function of pH, and when compared to the denatured peptide. These results indicate that the N-terminal domain of native PTH has considerable structure in solution, and are consistent with a theoretical model for the folding of this peptide.