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Blood donors reactive by enzyme-linked immunosorbent assay for antibody to the human immunodeficiency virus (HIV) who showed atypical patterns of viral core protein reactivity on Western blot were monitored for several months. Characterization of their antibodies was performed by 1) use of recombinant HIV proteins; 2) determination of cross- reactivity to HTLV-I, HTLV-II, and HTLV-IV: 3) assessment of immune status; and 4) identification of potentially interfering autoantibodies. Nineteen of 20 donors maintained the same HIV antibody reactivity throughout the follow-up period; the other donor became fully antibody-positive. Eighteen of 20 donors' sera showed clear reactivity with HIV recombinant core proteins. Ten of 19 donor samples demonstrated cross-reactivity to HTLV-IV; 3 of these 10 also cross- reacted with HTLV-I. The immune status of all donors was normal, although the medical histories and HLA antibody screens suggested possible autoimmune reactivity in 9 of 18 donors. During follow-up interviews, three donors reported possible risk factors for HIV infection that had not been acknowledged at the time of blood donation. We conclude that exclusion of donors with these atypical serologic test results is warranted while further studies to determine significance are being conducted.

The ABC synthetic anterior cruciate ligament (Surgicraft Ltd, Redditch, UK) is composed of polyester and carbon fibres combined in a partial braid. Following preconditioning this prosthesis exhibits mechanical compatibility with the natural anterior cruciate ligament and is intended for use as a biological scaffold for the ingrowth of autologous fibrous tissue.

Renal sonograms from 24 cats with confirmed parenchymal kidney disease and from 1 cat with radiographic and palpable evidence of renal enlargement (but without identifiable histologic abnormalities) were evaluated to describe the ultrasonographic appearance of feline renal diseases and to determine the role of ultrasonographic examination in the clinical evaluation of these cases. In all cats with radiographic evidence of abnormal renal size or contour and when poor intraabdominal radiographic contrast precluded visualization of the kidneys, ultrasonography provided complementary information pertaining to location (cortical/medullary), extent, and distribution (focal/multifocal/diffuse) of disease. Ultrasonography also characterized these lesions as cystic (cavitating) or solid. The echo patterns were most specific for renal cysts. Infiltrative diseases did not have consistent patterns. Multifocal hypoechoic nodules, diffuse cortical hyper-echogenicity, and normal-appearing parenchyma were identified. In these instances, however, ultrasonography did define the extent of disease and narrowed the spectrum of differential considerations.

Summary. NK cells from young normal mice are cytolytic in vitro for a virus-induced tumour cell line, YAC-1. Cytotoxicity is inhibited by the addition of unlabelled homologous YAC-1 cells and by regenerating bone marrow cells from the spleens of lethally irradiated, bone-marrow-grafted mice. Quiescent marrow from syngeneic and allogeneic mice produces little or no competition. This suggests that NK cells recognize, and may regulate, marrow progenitor cells.

The ability of the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) to induce the enzyme ornithine decarboxylase (ODC) and to stimulate DNA synthesis was studied in four different cell types in vitro. The effects of this agent on each cell type were different: (a) in hamster embryo cells, TPA induced ODC but had no effect on DNA synthesis; (b) TPA induced ODC and stimulated DNA synthesis in BALB/c 3T3 mouse cells; (c) it did not induce ODC in human fibroblasts but did stimulate DNA synthesis; and (d) it induced neither ODC nor DNA synthesis in rat embryo fibroblasts. In contrast to the effects of TPA, ODC was induced and DNA synthesis was stimulated in all cell types by fresh serum-containing medium. Treatment of the cells with a combination of fresh medium and TPA resulted in an approximate summation of the effects of treatment with each agent alone. These results emphasize the differences in the responses of various cells to TPA. They also show that in some cells, at least, the induction of ODC and stimulation of DNA synthesis following TPA treatment can be regulated independently.

Introduction A D U L T scoliosis is defined as one which presents after spinal maturity and is generally accepted in a patient who presents for treatment after 20 years of age. Unlike juvenile and adolescent scoliosis when the patient presents with deformity, adults with scoliosis present a wider range of symptoms or a symptom complex resulting in an unacceptable quality of life. Despite the high incidence. of infection, thrombosis, embolism and pseudarthrosis (Dawson et al, 1973; Kostuik et af, 1973; Ponder et al, 1975) the progressive deterioration in symptoms with increasing age (Bjure and Nachemson, 1973) combined with the ineffective, results of conservative measures forces the, patients to request surgical advice. We. reviewed a personal series of 9 adult patients who underwent spinal fusion to assess the success of spinal fusion in the relief of their symptoms.

Acute myocardial infarction can be stratified into electrocardiographic subsets based on the presence or absence of new Q waves. This stratification has important clinical and prognostic utility. Coronary angiography during acute non-Q-wave compared with Q-wave infarction shows much higher infarct-related artery patency rates (about 75 vs. 10%) and increased coronary collateralization. Culprit legion morphology in non-Q-wave infarction commonly is complex. The frequent demonstration of recurrent clinical ischemia, or residual thallium-201 uptake abnormalities, and metabolic activity on persistent emission tomography suggest the presence of viable myocardium in the distribution of the non-Q-wave infarction usually represents 20-25% of acute myocardial infarctions. The University of California San Diego Collaborative Postinfarction Database and other large studies have found non-Q-wave infarctions to be more common in patients with a history of previous infarction and congestive heart failure, although their mortality during acute hospitalization is lower. However, in long-term followup to one year and beyond, non-Q-wave infarct mortality rates equal those of Q-wave infarction. Patients at low early and late risk of mortality include those with a first infarction who are under age 70, whereas patients with evidence of residual ischemia postinfarction are at increased risk of events. It is interesting to speculate that the settings of unstable angina pectoris, non-Q-wave infarction, and perhaps the picture after thrombolysis for acute myocardial infarction, have pathophysiologic similarities which may carry implications for future research and therapy.

The induction of ornithine decarboxylase and S-adenosyl-L-methionine decarboxylase in mouse epidermis by various classes of tumor-promoting and nonpromoting compounds has been studied in order to determine the specificity of this response for tumor promotion. The effect of topical applications of a series of phorbol esters on these enzyme activities correlated well with their promoting abilities. Iodoacetic acid, anthralin, and Tween 60, all promoting compounds, also stimulated both of these enzyme activities after single and multiple applications. The hyperplastic agents acetic acid, cantharidin, and ethyl phenylpropriolate, however, had little effect on ornithine decarboxylase activity but a pronounced effect on epidermal S-adenosyl-L-methionine decarboxylase activity. The specificity of the ornithine decarboxylase response for tumor promotion was suggested by the results of the above experiments as well as the stimulatory effect of a completely carcinogenic dose of 7,12-dimethylbenz[a]anthracene; a lower initiating dose had no effect. In addition, epidermal tumors produced by a two-stage procedure showed consistently high levels of ornithine decarboxylase activity but variable levels of S-adenosyl-L-methionine decarboxylase activity.

The 55 S mammalian mitochondrial ribosome (referred to hereafter as "mitoribosome") is protein-rich, containing nearly twice as much protein as the Escherichia coli ribosome. In order to produce soluble mitochondrial proteins and protein-deficient subribosomal particles for use in functional and structural studies, the proteins of bovine mitoribosomes were extracted by washing in a series of buffers containing increasing concentrations of LiCl as the only chaotropic agent. LiCl disruption is used in order to preserve the solubilized proteins in a substantially "native" configuration. The extraction mixtures were characterized by sucrose density gradient analysis and the compositions of the stripped protein and residual pellet fractions were determined by two-dimensional polyacrylamide gel electrophoresis. In order to analyze the behavior or individual proteins, the intensity of Coomassie blue stain for each protein was normalized against the intensity of stain for the same protein in a control sample. Buffers with 1, 2, and 4 M LiCl each extract a specific subset of mitoribosomal proteins, while another group of proteins remains in the residual pellet fraction. Although very few proteins are detected in only one condition, most proteins are specifically enriched in one fraction. This LiCl procedure, therefore, produces fractionated groups of mitoribosomal proteins which can be used directly as a source for those proteins in which they are enriched, or they can be used as a starting point in further purification procedures. In contrast to results with E. coli ribosomes, several mitoribosomal proteins remain core-associated, indicating a different structural organization in these ribosomes.

A lateral radiograph of the pharyngeal region provides a technique for identifying pharyngeal disorders, including entrapment of the epiglottic cartilage and dorsal displacement of the soft palate. Epiglottic cartilage length, predicted from radiographs by measurement from the body of the thyroid cartilage to the tip of the epiglottis (thyroepiglottic length), was well correlated to actual length at postmortem examination (r2 = 0.98). Thyroepiglottic length, corrected for magnification, was 8.76 +/- 0.44 cm in 24 healthy Thoroughbreds. Nine Thoroughbreds with entrapment of the epiglottic cartilage and 6 with dorsal displacement of the soft palate had significantly short thyroepiglottic lengths--6.59 +/- 0.33 cm and 6.43 +/- 0.40 cm, respectively. The nasopharyngeal diameter of the Thoroughbreds with dorsal displacement of the soft palate was significantly less than the nasopharyngeal diameter of healthy Thoroughbreds. There was no significant difference between healthy and abnormal Thoroughbreds for pharyngoepiglottic, laryngeal, or tracheal measurements as determined from the lateral radiographs. The head should be placed in a normal resting position to obtain the pharyngeal radiograph. Maximum dorsiflexion of the head significantly increased the pharyngoepiglottic distance, whereas maximum ventriflexion significantly decreased this distance. The nasopharyngeal diameter during dorsiflexion was significantly greater than during ventriflexion. This investigation documented that a lateral pharyngeal radiograph provides important diagnostic information for evaluating suspected pharyngeal disorders in Thoroughbreds with airway obstruction of the cranial part of the respiratory tract.

We used an animal model of Pseudomonas keratitis to compare treatment by topical tobramycin with and without the presence of a commercially available collagen corneal shield. Pilot studies showed a significant, 30-fold increase in penetration of tobramycin into the anterior chamber in eyes with a collagen shield in place. Twenty albino rabbit eyes were inoculated with P. aeruginosa to produce stromal keratitis. After 12 hours of topical tobramycin dosing, eyes with a collagen corneal shield in place had a statistically significant (P less than .01) decrease in colony forming unit counts in comparison to treated eyes without a shield and control eyes.

Two methods were analyzed for the rapid extraction of equine fibrinogen from fresh plasma, using ammonium sulfate-sodium phosphate buffer. Fibrinogen from each of these 2 methods was then radiolabeled with 125I (half-life = 60.2 days, gamma = 35 keV), using monochloroiodine reagent. Mean protein-bound activity was 98.5% and mean clottable radioactivity was 94.1%. Radiolabeled fibrinogen administered IV to 15 horses had an overall mean (+/- SD) plasma half-life of 4.95 +/- 0.44 days.

The effects of tumor-promoting phorbol diesters on ornithine decarboxyalse (ODC) activity and DNA synthesis in normal and chemically transformed hamster embryo fibroblasts (HEF) in culture were studied. Only those phorbol diesters with promoting activity in mouse skin induced ODC in HEF. ODC was induced in both cell types by 12-O-tetradecanoyl-phorbol-13-acetate (TPA); maximal induction occurred 4 to 6 hr after the addition of the promoter to the medium of confluent cultures and was greater in transformed cells than in normal cells. The extent of induction in transformed cells treated with 0.016 to 1.6 micron TPA was dose dependent. The cellular concentrations of the polyamines, particularly putrescine, also increased after TPA treatment. The addition of TPA to confluent cultures of either normal or transformed HEF did not produce an increase in cell number or the percentage of [3H]thymidine- labeled nuclei and did not stimulate the incorporation of [3H]thymidine. ODC also was induced by adding fresh medium to the cultures. When both fresh medium and TPA were added, the effect of the medium was markedly potentiated in transformed, but not in normal, cells. These experiments demonstrate that tumor promoters specifically induce ODC in HEF without increasing the rate of DNA synthesis and that normal and transformed HEF differ in the levels of ODC activity attained after exposure to promoters.

S. typhi strains harboring R plasmids are a common finding in Mexico City hospitals. The predominant R plasmids share the following properties: they belong to the same incompatibility group (H1)’ have a molecular weight of 135 Mdal, carry a temperature sensitive transfer system, and code for the resistance to Cm, Sm, Su, Hg and Tc. The general organization of the resistance genes resembles that of RlOO, since homogenic derivatives which have lost the r-determinants, Tn1O or all the resistance genes can be isolated in vitro by several methods. Furthermore, naturally occurring a-plasmids deleted for the r-determinants or Tn1O have been found, although at low frequency. Complementation experiments indicated that the ts transfer system of the mexican plasmids is not related to that of Flac, Rl-19 or Col Ibdrd.

Early cellularization of the free-nuclear endosperm and subsequent differentation of the aleurone cells in the ventral region of the developing wheatgrain (Triticumaestivum L. cv. Heron) were examined using both light and electron microscopy. In ovules harvested 1 d after anthesis, irregular wall ingroths typical of transfer cells protrude into the multinucleate cytoplasm. Initital cellularization occurs by a process of free wall formation in much the same fashion as in the dorsal region of the grain. In places, sheets of endoplasmic reticulum and dictyosomes appear to be closely associated with the growing wall. Like the wall ingrowths noted earlier, the freely growing walls are intensely fluorescent after staining with aniline blue. Initiatal cellularization is complete 2–3 days after anthesis. Unlike the first-formed cells in the dorsal region of the developing grain, those in the ventral region are not meristematic. These amitotic cells become the groove aleurone cells which at an early stage of development are set apart from the rest of the endosperm by their irregularly thickened walls and dense cytoplasm. Autofluorescence is first apparent in the walls of those cells next to the degenerating nucellus. In contrast to the aleurone cells in the dorsal region of the grain, at maturity only the inner wall layer of each of the groove aleurone cells remains autofluorescent. The aleurone grains are highly variable in appearance and contain no Type II inclusions.

We used a rabbit model of bacterial keratitis to assess in vivo efficacy of topical imipenem, a highly potent beta-lactam antibiotic with an unusually broad spectrum of activity, including aminoglycoside-resistant Pseudomonas aeruginosa. Albino rabbits received intrastromal injections of 5 x 10(2) organisms of an aminoglycoside-resistant strain of P. aeruginosa. At five hours postinoculation, imipenem (5 mg/ml) therapy was initiated using one drop per 30 minutes for 12 hours. Corneal tissue was then excised for colony forming unit counts. Imipenem was highly effective in reducing colony forming unit counts to zero in comparison to 4.1 x 10(5) organisms for untreated controls. A second regimen beginning 24 hours postinoculation of one drop per hour for 24 hours was also successful in significantly reducing colony forming units vs controls (P less than .05). These data suggest that topical imipenem may have clinical applicability in the treatment of P. aeruginosa keratitis.

The clinical effectiveness of bovine lung heparin and porcine intestinal heparin for reducing arterial thrombosis was compared in a study of 64 surgical patients (mean age, 63.8 years). Immediately prior to operation, the radial artery was cannulated. The catheters were flushed continuously at a flow rate of 3 ml/hr with 0.9% sodium chloride solution without heparin or with two units per milliliter of either beef lung or pork intestinal mucosa heparin. After 24 hours, arteriography was performed, and vessel diameter and the amount of thrombus present were recorded. The addition of heparin to the flush solution significantly reduced the accumulation of thrombotic material on the surface of intra-arterial cannulae, thus lowering the incidence of clinically detectable arterial occlusion. No significant difference was found in the anticoagulant effectiveness of beef lung-derived heparin as compared with heparin obtained from pork intestinal mucosa.

Renal hyperparathyroidism can be a major clinical problem in those receiving dialysis treatment and in those having renal transplants. This review of 66 patients during a five year period has led us to believe that laboratory data are useful for confirming the clinical diagnosis or for following the outcome of medical or surgical therapy. The screening for renal hyperparathyroidism should be on clinical grounds and not on isolated biochemical tests. All patients with renal failure, whether receiving dialysis therapy or renal transplantation, are at risk for having renal hyperparathyroidism develop. A careful assessment of the clinical and biochemical data is required to ensure proper patient selection for operation. Bone disease and persistent pruritus unresponsive to medical management remain the principle clinical indications for operation. Our preferred procedure is the standard subtotal parathyroidectomy.

The preprophase band of microtubules is known to predict the future plane of cytokinesis accurately in both symmetric and asymmetric divisions of the cell. Of the three major types of cytokinetic systems which are now known, so far there are no reports of systems that divide by cleavage having preprophase bands of microtubules. It is proposed that a major function of a preprohase band is to prevent the initiation of cleavage in systems which require the development of a phragmoplast to hold daughter nuclei apart after telophase.

A case is described in which diabetes insipidus was associated with hypopituitarism, insulin-independent diabetes mellitus, pernicious anaemia and circulating antibodies to the thyroid gland, adrenal gland and the pancreatic islet cells.

A method is presented for the in vitro isolation and radiolabeling of equine platelets with the isotope indium 111 (111In: half-life = 2.8 days, gamma = 173 keV, 89%; 247 keV, 94%). The technique described involves complexing 111In with the lipid-soluble chelating agent, 2-mercaptopyridine-N-oxide (merc), in an aqueous medium. 111In-merc platelet-labeling efficiencies in autologous plasma pretreated with or without ferric citrate reagent were 82 +/- 7% and 24 +/- 12%, respectively. Mean intravascular survivals of 111In-merc-radiolabeled platelets in 8 healthy horses according to simple linear, exponential, mean, weighted-mean residual sum of squares analysis, and multiple-hit model were 5.5 +/- 0.49, 3.5 +/- 0.53, 4.5 +/- 0.18, 4.3 +/- 0.65, and 3.6 +/- 0.97 days, respectively.

Phorbol ester tumor promoters and growth factors rapidly stimulate ornithine decarboxylase activity in the transformed hamster fibroblast line HE68BP. We report here a close correspondence between the time courses and magnitudes of induction of ornithine decarboxylase activity and immunoreactive ornithine decarboxylase protein following treatment of HE68BP cells with 12-O-tetradecanoylphorbol 13-acetate (TPA) and/or refeeding with fresh medium. Cycloheximide addition to induced cells caused a rapid fall in the levels of both ornithine decarboxylase activity and ornithine decarboxylase protein. Northern blot analysis of RNA isolated from HE68BP cells indicated that treatment with TPA and fresh medium increased the amount of two species of mRNA of lengths 2.4 and 2.1 kilobase. This increased accumulation of ornithine decarboxylase mRNA corresponded temporally to that observed at the protein level, with a 15-fold maximal induction 7 h after treatment followed by a rapid decline in hybridizable RNA. These data indicate that stimulation of ornithine decarboxylase activity by TPA or refeeding involves changes in levels of ornithine decarboxylase mRNA as well as changes in the rate of synthesis of ornithine decarboxylase protein.

The behavior of coal ash and corrosive alkali species in a gas turbine fueled by an ultra-clean coal water mixture (UCCWM) is investigated. A thermochemical equilibrium analysis is first conducted to study the effect of coal cleaning on the extent of vaporization of ash constituents. It is found that for a selected bituminous coal, cleaned up to 10% of the initial ash content, the amount of Ca, Mg, Si and Al vaporized is independent of coal cleaning and that of Na, K and Fe directly proportional to the degree of coal cleaning. In order to study the fate of the vaporized constituents, a gas-to-particle conversion (condensation) model is formulated. The aerosol processes of homogeneous nucleation, heterogeneous nucleation, particle agglomeration, particle deposition, as well as direct vapor deposition on boundary surfaces are included in the formulation. The aerosol formation calculations are driven by the gas phase equilibrium chemistry of twelve elements and twenty seven gaseous species. The model is partially validated by comparison against available laboratory data on ash nucleation in a laminar flow furnace. Application of the model to UCCWM gas turbine system indicates that the characteristic condensation time of sodium and potassium sulfates is much smaller than the residence time in gas turbine, that in spite of the presence of numerous nucleated ash particles the alkali sulfates undergo self-nucleation, and that thermophoresis and Brownian motion are expected to be the primary mechanisms of sulfate deposition on turbine blades.

The phorbol ester TPA (12-O-tetradecanoylphorbol-13-acetate) stimulates baseline Na+ transport across frog skin epithelium and partially inhibits the natriferic response to vasopressin. The effects are produced largely or solely when TPA is added to the mucosal surface of the tissue. Although TPA activates protein kinase C, it has other effects, as well. Thus, the biochemical basis for the effects and the ionic events involved have been unclear. Furthermore, the physiologic implications have been obscure because of the sidedness of TPA's actions. We now report that two synthetic diacylglycerols (DAG) replicate the stimulatory and inhibitory effects of TPA on frog skin. DAG is the physiologic activator of PKC. In this tissue, it produces half-maximal stimulation at a concentration of less than or equal to 19 microM. In contrast to TPA, DAG is about equally effective from either tissue surface. In a series of eight experiments, DAG was found to depolarize the apical membrane. Diacylglycerol also increases the paracellular conductance of frog skins bathed with mucosal Cl- Ringer's solution. The latter effect can be minimized by replacing NO3- for Cl- in the mucosal solution. Under these conditions, combined intracellular and transepithelial measurements indicated that DAG increased both the apical Na+ permeability and intracellular Na+ concentration. These results are qualitatively similar to the effects of cyclic 3',5'-AMP on this tissue, suggesting that activation of PKC by DAG causes phosphorylation of the same or nearby gating sites phosphorylated by cAMP. We propose that apical Na+ entry is regulated in part by activation of PKC, and that insulin may be a physiologic trigger of this activation.

One goat anesthetized with thiamylal sodium, xylazine, and halothane for repair of an abominal hernia, and 7 of 29 goats similarly anesthetized for an experiment unrelated to considerations of anesthesia, developed signs of hepatic failure within 24 hours of anesthesia. Affected goats had high values for serum aspartate transaminase and serum total bilirubin by 12 to 24 hours after induction of anesthesia. Necropsy of the 8 affected goats revealed centrilobular to massive hepatic necrosis (8 of 8), brain lesions consistent with hepatic encephalopathy (3 of 4), and acute renal tubular necrosis (6 of 6). Two unaffected goats had no hepatic necrosis. Causes of hepatic necrosis other than those related to anesthesia (eg, infectious agents, toxins) were ruled out by lack of supporting necropsy findings or were considered unlikely because of lack of opportunity for exposure. Hepatic lesions in these goats closely resembled those described in human beings with halothane-associated hepatic injury, although in both species these lesions are nonspecific at the gross and light microscopic levels. The pathogenesis of halothane-associated hepatic injury in goats, as in human beings, remains to be determined.

Nursing infants may potentially be affected by any drug ingested by the mother; this report provides a tabulated listing of drugs present or absent in human milk and attempts to evaluate their significance to the nursing infant. Certain enzyme systems which detoxify drugs in the adult are not present in the neonate. Chloramphenicol and sulfisozazole are examples of such enzyme-dependent systems and may cause kernicterius and Gray syndrome. Psychological and physiological factors can affect the composition of the milk and alter the transfer of various drugs into the milk. Passive diffusion is the main mechanism of transfer of drugs from plasma to milk, but other important means include lipid solubility, route of drug administration drug dissociation constants, protein binding phenomena and active transport. A table lists drugs, their excretion and significance for nursing in the following categories: 1) antihistamine drugs, 2) antiinfective agents, 3) antineoplastics, 4) autonomic drugs, 5) blood formation and coagulation, 6) cardiovascular drugs, 7) central nervous system drugs, 8) diagnostic agents, 9) electrolytic caloric and water balance, 10) expectorants and cough preparations, 11) gastrointestinal drugs, 12) hormones and synthetic substitutes, 13) radioactive agents, 14)serums, toxoids, and vaccines, 15) skin and mucous membrane preparations, and 16) vitamins.

A single topical application of 1.0 mg of crotol oil or 17 nmoles of 12-O-tetradecanoyl-phorbol-13-acetate (TPA) resulted in a rapid, transient stimulation of mouse epidermal ornithine decarboxylase activity. The activity reached a peak (230-fold greater than control after TPA) at 4 to 5 hr after croton oil or TPA treatment and returned to control level by 12 hr. The stimulation of S-adenosyl-L-methionine decarboxylase activity was less pronounced, reaching a peak of activity (6- to 7-fold greater than control) at 9 to 12 hr after TPA or croton oil and slowly declining to control level. The stimulation of both enzyme activities was dependent on the dose of TPA applied and correlated well with the promoting ability of these doses on mouse skin. Phorbol, the nonpromoting parent alcohol of TPA, did not affect the enzymes activities. Cycloheximide pretreatment abolished the increase in enzyme activities after TPA application. By measuring the decline of enzyme activity following cycloheximide treatment, enzyme half-lives of 17 and 41 min were obtained for ornithine and S-adenosyl-L-methionine decarboxylase, respectively. 5-Azacytidine pretreatment prevented the stimulation of enzyme activities by TPA, while actinomycin D had no effect. Cordycepin (3'-deoxyadenosine) partially blocked the rise in enzyme activities.

Summary Fibrinolytic activity in the gastric juice of normal subjects has been studied by a double-blind cross-over technique comparing the effect of placebo and pentagastrin against aspirin and pentagastrin. Aspirin effectively produced a gastritis and pure fibrinolytic activity was detected in the gastric juice, but the number of samples showing pure fibrinolytic activity did not differ between the two groups. In both the placebo and the aspirin groups the presence of a protease active at neutral pH and capable of dissolving fibrin is confirmed. Aspirin is unlikely to cause gastric bleeding by increasing local fibrinolytic activity within the stomach. The model, so constructed, is not sensitive enough to be of value in investigating further the role of gastric fibrinolytic activity in gastric haemorrhage.

To assess the relative exposure of individual ribosomal proteins (r-proteins) in the large and small subunits of the bovine mitochondrial ribosome, we used a double label iodination technique. Regions of r-proteins exposed in purified ribosomal subunits were labeled with 131I using the lactoperoxidase-catalyzed iodination system, and additional reactive groups available upon denaturing the r-proteins in urea were labeled with 125I using the chloramine-T mediated reaction. The ratio of 131I to 125I incorporated into individual proteins under these conditions is representative of the degree of exposure for each of the proteins in the subunits. In this manner, the r-proteins have been grouped into 3 classes depending on their degree of exposure: high exposure, intermediate exposure, and essentially buried. While both subunits have a few proteins in the "highly exposed" group, and a large number of proteins in the "intermediate exposure" group, only the large ribosomal subunit has an appreciable number of proteins which appear essentially buried. The more buried proteins may serve mainly structural roles, perhaps acting as "assembly proteins," since many from this group bind to ribosomal RNA. The more superficially disposed proteins may comprise binding sites for macromolecules that interact with ribosomes during protein synthesis, as well as stabilizing the association of the large and small subribosomal particles.

The ocular histopathological and ultrastructural features of fucosidosis in a man who survived to the age of 25 years are reported. Virtually all of the cells of the eye contained cytoplasmic, membrane-bound, and confluent areas of fibrillogranular and multilaminated material. The most striking accumulations were present within the endothelial cells lining blood vessels and corneal endothelium, and the least amount was present in the uveal melanocytes.

The induction of mouse epidermal ornithine decarboxylase, 1 of the earliest and largest phenotypic changes following treatment of mouse skin with the tumor-promoting agent, 12-O-tetradecanoyl-phorbol-13-acetate, can be inhibited by prior administration of colchicine. Maximal inhibition of this enzyme induction was observed when colchicine was injected i.p. 90 or 120 min before promoter treatment, although time intervals up to 20 hr between colchicine and promoter treatment were effective. The effect of colchicine was dose dependent, with a dose as low as 25 nmoles/mouse causing an inhibition of 35%. Other microtubule-disrupting agents, vinblastine, vincristine, and Colcemid, had a similar effect on ornithine decarboxylase activity. However, beta, gamma-lumicolchicine, a photochemical derivative of colchicine with no antimitotic or microtubule-disrupting ability, and cytochalasin B, an inhibitor of microfilament-dependent processes, had no effect. N6, O2'-dibutyryl 3',5'-cyclic adenosine monophosphate, when administered just before colchicine, blocked the inhibitory action of colchicine. The results of these studies suggest that colchicine-sensitive structures, most likely containing microtubules, may be mediating elements between the binding of tumor promoters, perhaps to specific cell surface receptors, and the subsequent induction of ornithine decdaboxylase.

The ultrasonic criteria for the diagnosis of gallbladder calculi are: (1) echo-dense structures which disturb the smooth contour of the posterior border of the gallbladder; (2) sonic shadowing, and (3) echoes from within the gallbladder. Diagnostic confidence increases greatly in cases in which internal echoes, contour irregularities, and sonic shadows have occurred simultaneously. A case is presented in which all three criteria are fulfilled, but which represents an artifact, i.e., "pseudostone." This was confirmed by varying the patient's respiration and showing that the "pseudostone" represented echoes from a loop of bowel which produced a significant impression on the posterior wall of the gallbladder during deep inspiration. The absence of cholelithiasis was confirmed by oral cholecystography.

Weanling male deer mice, Peromyscus maniculatus, were exposed for three weeks either to light-dark (LD) cycles with periods (T=L+D) ranging from T=23 (1L:22D) to T=25.16 (1L:24.16D) or to 24-h LD cycles with photoperiods ranging from 1 (1L:23D) to 19 (19L:5D) h. Both the circadian locomotor activity rhythms and the response of the reproductive system to these LD cycles were assessed. The results demonstrate that the photoperiodic effectiveness of light depends on the phase of the light relative to the animal's circadian system, as marked by the circadian activity rhythm. Light falling during the animal's subjective night, from activity onset to at least 11.8 h after activity onset, stimulates growth and maturation of the reproductive system, whereas light falling during the rest of the circadian cycle is nonstimulatory.

CP1 is a yeast protein which binds to the highly conserved DNA element I (CDEI) of yeast centromeres. We have purified CP1 to near homogeneity; it is comprised of a single polypeptide of molecular weight 58,400. When bound to yeast CEN3 DNA, CP1 protects a 12-15-base pair region centered over CDEI. Methylation interference experiments show that methylations of residues located outside of the 8-base pair CDEI sequence have no detectable effect on CP1 binding, suggesting that the DNA sequences important for CP1 recognition are confined to the CDEI octanucleotide. The equilibrium constant for CP1 binding to CEN3 DNA is relatively low, 3 x 10(8) M-1. Using a novel method to determine relative DNA binding constants, we analyzed the effect of CDEI mutations on CP1 binding. A C to T point mutation at position 5 (CO1) reduces the equilibrium constant about 35-fold, while the insertion of an additional T at this position (CAT) reduces the equilibrium constant 1,400-fold. The effect of these mutations on mitotic centromere function in vivo was assessed using a plasmid stability assay. While the CO1 mutation had a slight effect, the CAT mutation significantly impaired function, implying that CP1 binding is required for the optimal mitotic function of yeast centromeres.