Management of infectious endophthalmitis by combined vitrectomy and intraocular injection

Combined therapeutic vitrectomy and intraocular antibiotic injection were used as a primary treatment for infectious endophthalmitis after diagnostic vitreous tap on seven patients. Two patients also received penetrating keratoplasty in addition to vitrectomy. Postoperatively, two patients achieved visual acuity of 20/30 or better, and five patients achieved 20/100 or better. One eye was enucleated.

A simple, inexpensive sterile vitreous specimen collection device with peyman vitreophage

A simple and inexpensive vitreous specimen collection device is described. This device can be connected to the Peyman Vitreophage System to obtain a sterile intraocular specimen during a pars plana virectomy.

Turbulent blood flow in the ascending aorta of dogs

A conical hot film anemometer probe was used to measure instantaneous velocities in the ascending aorta of anaesthetised, open-chest dogs. The probe was mounted on a saddle which allowed traversal of the aorta in 1 mm increments 4 cm above the aortic valve. From these point measurements, the radial distribution of velocity was obtained by averaging ten cardiac cycles. The contractile state of the heart was increased by sequential intravenous infusions of isoprenaline. The absolute peak centreline velocity in the baseline state ranged from 28 to 56 cm x s-1 and, in 20 micrograms x min-1 isoprenaline infusion, from 39 to 112 cm x s-1. Two major effects of isoprenaline on blood flow were noted: 1) isoprenaline dramatically increased peak centreline velocity, and 2) disturbances resembling turbulence appeared as peak velocity increased. With isoprenaline infusion disturbances existed throughout the deceleration portion of the aortic blood flow. Analysis of the frequency components of the velocity wave was performed, and significantly higher frequency components up to 100 Hertz were found in the turbulent cases compared to the laminar ones. Turbulent flow or disturbed flow is found when the ratio of Reynolds number to Womersley number is above 200. In general the hot film measurements showed that both laminar and disturbed velocity profiles tended to be flat throughout the cardiac cycle, with the sharp velocity gradient confined to the region of the wall. Turbulent normal stress during the deceleration portion of aortic blood flow were found in the orders of 15 to 30 dynes x cm-2 and the wall shear stresses were found to be from 10 dynes x cm-2 at the baseline condition to 50 dynes x cm-2 during the 20 micrograms x min-1 isoprenaline infusion.

Nocardia asteroides endophthalmitis

A case of exogenous Nocardia asteroides endophthalmitis with impending corneal perforation was diagnosed by culture and successfully treated with vitrectomy, penetrating keratoplasty, and intraocular, topical, and systemic antimicrobial therapy. The patient regained excellent vision.

Effect of valve orientation on flow development past aortic valve prostheses in a model human aorta

The effect of valve orientation on flow development in a model human aorta was studied by means of a qualitative flow visualization technique. The model replicated the geometry of the human aorta and the experiment simulated a physiologically realistic pulsatile flow. The following valves were studied: Starr-Edwards Stellite, Starr-Edwards silicone, Björk-Shiley spherical disc, Björk-Shiley convexo-concave disc, and Hall-Kaster tilting disc. All the valves had a tissue anulus diameter of 27 mm. With the ball-in-cage valves, the flow in the ascending aorta was predominantly axial and uniform throughout systole, while vortex formation was observed downstream from the ball. With the tilting disc valves, the flow development in the aorta was a function of the orientation of the valves. With the major flow orifice directed toward the commissure between the right and noncoronary cusps, the fluid motion was predominantly in the axial direction through early systole. A vortex developed along the wall of lesser curvature of the aorta with the progression of systole. In early diastole, a well-defined flow reversal was observed along the lesser curvature of the aorta. With the major flow orifice directed toward the left coronary cusp, the fluid motion, although predominantly axial, was not uniform in the ascending aorta. Regions of relative stasis present near the wall of greater curvature subsequently developed into a trapped vortex throughout the cardiac cycle. With the major flow orifice directed more posteriorly, an improved fluid dynamic characteristic was observed, and there was no trapped vortex present near the wall of greater curvature. The flow visualization study in the model human aorta suggests that, from a fluid dynamic point of view, orientation of the major flow orifice of the tilting disc valve toward the wall of lesser curvature is not advisable.

Reversible neuromuscular blocking action of carboxymethylated alpha-bungarotoxin

Carbamidomethylation of the reduced Cys29-Cys33 bridge of alpha-bungarotoxin (Bungarus multicinctus postsynaptic neurotoxin) did not alter the LD50 or irreversibility of the toxin, while carboxymethylated alpha-bungarotoxin was less potent and its neuromuscular blocking action in mouse diaphragm was reversible. The circular dichroic spectra of both modified toxins were similar but slightly different from that of native toxin. Neuromuscular transmission in the chick biventer cervicis nerve-muscle preparation could be blocked by the carboxymethylated toxin, and reactivated by washing, whereas the response of the muscle to extrinsic acetylcholine could also be blocked but was hardly restored by washing. These results suggest that carboxymethylated toxin can differentiate between junctional and extrajunctional acetylcholine receptors in chick skeletal muscle.

Laser anemometry measurements of pulsatile flow past aortic valve prostheses

Experimental results are presented on physiological pulsatile flow past caged ball and tilting disc aortic valve prostheses mounted in an axisymmetric chamber incorporated in a mock circulatory system. The measurements of velocity profiles and turbulent normal stresses during several times in a cardiac cycle were obtained using laser-Doppler anemometry. Our results show that with increased angle of opening for the tilting disc valves, a large but locally confined vortex is observed along the wall in the minor flow region throughout most of the cardiac cycle. The turbulent normal stresses measured downstream to the tilting disc in the minor flow region parallel to the tilt axis were found to be larger than those measured downstream to the caged ball valves. Comparison of measurements with steady flow at flow rates comparable to peak pulsatile flow rate show that the turbulent normal stresses are larger by a factor of two in pulsatile flow with a frequency of 1.2 Hz.

Steady flow development past valve prostheses in a model human aorta. I. Centrally occluding valves

In this paper, laser-Doppler anemometry measurement of steady flow development in a model human aorta has been reported. Studies were made with uniform entry flow at the root of the aorta and our measurements showed the establishment of a pair of Dean vortices in the mid-arch region. Subsequently, the nature of flow development past centrally occluding caged ball valves in the model aorta was investigated. Our studies showed that in the ascending aorta, an asymmetric velocity profile is obtained with larger velocity gradients towards the inner wall of tertiary curvature (anatomically the left lateral wall) with centrally occluding valves. The peripheral flow past these valves prevented the development of Dean vortices in the mid-arch region. The caged ball valves at the root of the aorta had no discernible effect on the velocity profiles in the brachio-cephalic artery.

Steady flow development past valve prostheses in a model human aorta. II. Tilting disc valves

The flow development in the model human aorta with uniform entry as well as with centrally occluding valves mounted at the root of the aorta was described in Part I of this two-paper sequence. Part II deals with the flow development in the model aorta with tilting disc valves mounted at the root of the aorta. Bjork-Shiley and Hall-Kaster tilting disc valves were mounted in three different orientations with respect to the root of the aorta. The velocity profiles and turbulent stresses were measured with laser-Doppler anemometry. Our results under steady flow conditions in the model human aorta show quantitatively that the flow development in the ascending aorta as well as in the brachio-cephalic artery are strongly dependent on the orientation of the tilting disc valves. With the valves tilting towards the outer wall of curvature, our results suggest a tendency for flow separation at the flow divider region of the brachio-cephalic artery.

Geographic distribution of HBsAg carriers in China

We tested by radioimmunoassay the sera of 22,707 male Chinese government employees in Taiwan for HBsAg and found 15.2% to be positive. Almost all were confirmed as carriers by follow-up testing 1 year later. This paper presents HBsAg positivity rates of these men according to the province of China from which they originated, and compares the rates with published provincial mortality rates for primary hepatocellular carcinoma. Moderate variation in carrier rates between provinces was observed with high prevalence in men from provinces south of the Yangtze River. There was positive correlation between HBsAg prevalence and primary hepatocellular carcinoma incidence giving further support to the possibility of a causal relationship.

Comparative rates of elimination of some individual polychlorinated biphenyls from the blood of PCB-poisoned patients in Taiwan

In 1979, a mass outbreak of poisoning occurred in Central Taiwan due to the ingestion of rice-bran oil contaminated with polychlorinated biphenyls (PCBs). The major PCB isomers and congeners in the toxic rice oil and in the blood of PCB-poisoned patients were characterized by gas chromatography and gas chromatography/mass spectrometry using a highly efficient glass capillary column. The elimination of some major individual PCBs from blood of these patients was studied. The results indicate that tetra- and pentachlorobiphenyls with adjacent unsubstituted carbon atoms at meta-para positions are rapidly eliminated from the blood of patients, while PCBs with the same degree of chlorination but with adjacent unsubstituted carbon atoms at ortho-meta positions are eliminated more slowly. The results also indicate that most of the hexa- and heptachlorobiphenyls, with adjacent unsubstituted carbon atoms at ortho-meta positions of the biphenyl ring, are eliminated very slowly. Laboratory-animal studies have indicated that PCB excretion depends primarily on the rate of metabolism; therefore these differences in rates of elimination of PCBs should reflect the differences in their rates of metabolism.

Impaired pulmonary function as a risk factor for mortality

Prospective follow-up information obtained between 1976 and 1981 on mortality among 2539 individuals showed that pulmonary function impairment is a risk factor for short-term mortality, even when risk factors such as age, sex, and smoking are considered. Predicted risk curves for impaired individuals (those with forced expiratory volume in one second less than 68% of forced vital capacity) are consistently higher among all race-sex categories over all ages. Survival analysis using the proportional hazards model shows a steeper decline in estimated survival among individuals with poor pulmonary function compared to those with good pulmonary function, adjusted for age, race, and smoking effects. These observations are consistent with the concept that impairment of pulmonary function is a risk factor for morbidity and mortality from several nonrespiratory as well as respiratory diseases and that it acts by contributing to various pathogenic mechanisms in different organ systems.

Squalene in Petroleum Asphaltenes

Squalene, 2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene, a new biological marker, has been detected in various petroleum asphaltenes and their pyrolysis products. Since squalene is the most common triterpenoid in nature and the biological precursor of the important tetra- and pentacyclic triterpane markers, its detection in asphaltene suggests new ways for marker correlations.

Dietary selenium and age-related susceptibility of rat erythrocytes to oxidative damage

The effects of age and dietary selenium on cellular susceptibility to oxidative stress were studied in rat erythrocytes. Young (26 or 40 days) and mature adult (11 or 15 months) male rats were fed a Torula yeast-based low selenium and low vitamin E diet supplemented with either 0, 1.0 to 2.0 ppm selenium (as sodium selenite) for 5 weeks. The rates of spontaneous hemolysis amd methemoglobin formation and levels of glutathione (GSH), glucose-6-phosphate (G6P) dehydrogenase, but not of GSH peroxidase, GSH reductase, superoxide dismutase and catalase were significantly higher in the erythrocytes of young rats than in those of the adults. Adult rats, however, had higher levels of plasma vitamin E and GSH peroxidase than those of the young group. Dietary selenium markedly increased activity of plasma GSH peroxidase and partially retarded the rates of hemolysis and methomoglobin formation, but it had no significant effect on the erythrocyte levels of GSH, GSH reductase, catalse, G6P dehydrogenase and superoxide dismutase or plasma vitamin E levels of young rats. Except of GSH peroxidase activity, dietary selenium had no significant effect on any other measurements made in the erythrocytes or plasma of adult rats. The results suggest that the ability of adult rats. The results suggest that the ability of adult rats to retain higher levels of vitamin E and selenium than the young rats may be partly responsible for the increased resistance of their erythrocytes against oxidative stress.

Neutron activation analysis of microleakage around a hydrophobic composite restorative

Neutron activation analysis with dysprosium as a tracer was employed to determine quantitatively the microleakage around the restorations of an experimental hydrophobic composite, as well as a commercial composite. Only a negligible uptake of tracer was obtained for the experimental composite, whereas a five-fold uptake was recorded for the commercial composite. Capillary penetration of fluid around a restoration could be greatly reduced by using a hydrophobic composite.

Misalignment characteristics of resonators formed by 90 degrees cone and mirror

The stability condition of a resonator formed by a 90 degrees cone and mirror has been derived using ray tracing techniques. The result showed that this type of resonator is relatively insensitive to mirror misalignment. From this basis, the mirror misalignment tolerance was studied experimentally. Output energy and transverse mode characteristics vs. misalignment were measured, and the results show that this type of resonator does possess certain advantages over the two-mirror resonator.

Regional pressure differences in the left ventricle

Theoretically, if blood is to have directional flow and different magnitudes of velocity, pressure should be distributed in the left ventricle (LV) as a function of both space and time. Thus, regional pressure differences (RPD) were examined in the LV of 20 open-chested dogs. High-fidelity transducers were implanted through stab wounds at three positions in the LV: the base (B), equator (EQ), and apex (APX). Simultaneous, high-fidelity LV pressures were compared in each region under rest conditions and during graded infusions of isoproterenol and propranolol. In the baseline condition, there were slight but significant differences between the APX and B in end-diastolic pressure (EDP), peak systolic pressure (PSP), peak dp/dt and Vmax. At rest, the largest RPD between the APX and B in PSP was 9 mm Hg (mean +/- 1 SE = 2.1 +/- 0.5), and the largest during diastole was 5.1 mm Hg (mean +/- 1 SE = 1.2 +/- 0.4); the largest difference in Vmax was 30.5% (mean +/- 1 SE = 10.8 +/- 2.4). During isoproterenol infusion the RPD in PSP were accentuated; the largest seen was 84 mm Hg between APX and B (mean +/- 1 SE = 15.7 +/- 4.5). The largest difference in Vmax between B and APX was 188% (mean +/- 1 SE = 48.5 +/- 9.4). Propranolol obliterated these RPD. These results indicate that there are significant RPD in the LV cavity; during systole the highest pressures decrease sequentially from the apex to the equator and to the base; during diastole these RPD are of lesser magnitude. These RPD affect all derived pressure indices, and these changes can be increaed or decreased by drug intervention. These results are important for two reasons: 1) the position of catheters in the LV cavity is important when pressure-dependent LV parameters are compared in different conditions; and 2) in any force balance analysis of the left ventricle it is important to note that force generation by the left ventricle is an active process that transmits regional pressure differences to the LV cavity.

Interaction of factors associated with cancer of the nasopharynx

A retrospective study of nasopharyngeal carcinoma (NPC) revealed that smoking, working under poor ventilation, use of nasal balms or oil for nasal and throat troubles, use of herbal drugs, and anti-EBV antibody titer were found statistically associated. The dural interactions of these factors to the risk of NPC were presented. Except in work conditions with poor ventilation and when herbal drugs are used, all the combinations were synergistic. The synergistic actions were especially remarkable with smoking and other factors. The possible etiological mechanisms of NPC are discussed.

A new composite restorative based on a hydrophobic matrix

A hydrophobic restorative composite based on a fluorocarbon analog of an alkyl methacrylate and a bisphenol adduct was formulated into a one-paste system, which polymerized in the presence of blue light. Physical, mechanical and water-related properties were determined. High contact angles and low water sorption were shown by the experimental composite. Capillary penetration of oral fluids around restorations, therefore, could be prevented in the presence of this highly hydrophobic surface. The physical and mechanical properties of the experimental composite were either comparable to or somewhat less favorable than commercial Bis-GMA composites.

Gonadal receptors. I. Evidence for irreversibility in the binding of human chorionic gonadotropin and human luteinizing hormone

The binding of human chorionic gonadotropin and human luteinizing hormone to particulate receptors of rat testes has generally been assumed to follow an equilibrium model similar to that proposed for many enzyme systems. Our work shows that equilibrium dissociation constant (Kd) and number of hormone binding sites (Bmax) are highly sensitive to changes in hormone and/or receptor concentration and to treatment received by tissue or receptor preparation prior to the assay. The results of binding assays obtained using receptor preparation pretreated with hormone (labeled as well as unlabeled) indicated that the binding reaction between hormone and receptor was irreversible and that pretreatment of the tissue with hormone greatly alters the number of high affinity gonadotropin binding sites in the testicular homogenate. Data from studies involving increasing receptor concentrations revealed that increasing the mass of particulate receptors in the binding assays leads to higher Kd as well as Bmax values. These findings are incompatible with a binding model based upon occupancy of receptor sites and the state of equilibrium implied. The incompatibilities are analyzed and an alternate model advanced (Bhalla, V.K., Trowbridge, C.G., Chen, C.J.H., Lindeman, J.G. and Rojas, F.J. (1979) Biochim. Biophys. Acta 584, 436--453).

Gonadal receptors. II. Effects of time and reaction volume upon the binding of human chorionic gonadotropin and human luteinizing hormone to particulate receptors

The effect of reaction volume upon the binding of gonadotropins by particulate receptors was studied. Two experimental approaches were used: one involved increasing the reaction volume of the binding assay (i.e. diluting the hormone and receptor concentrations and will be referred to as buffer coincubation studies) and the other involved incubating the testicular homogenate in various buffer volumes prior to the binding assay (buffer preincubation stidies). The results showed that the number of hormone binding sites inferred from Scatchard analysis was inversely related to the reaction volume in the coincubation as well as in the preincubation studies. Time-dependent dissociation of receptors from the intact testis was demonstrated by perifusion studies and the loss of receptors from intact testis correlated with the appearance of soluble factors (Bhalla, V.K., Haskell, J., Grier, H. and Mahesh, V.B. (1976) J. Biol. Chem. 251, 4947--4957) in the eluate obtained. The results obtained along with those presented in the preceding manuscript (Chen, C.J.H., Lindeman, J.G., Trowbridge, C.G. and Bhalla, V.K. (1979) Biochim. Biophys. Acta 284, 407--435) question the validity of the rapid equilibrium model which assumes reversible hormone occupancy of a fixed number of receptor sites. An alternate binding model is proposed herein and its implications are discussed.

Hb Leslie, an unstable hemoglobin due to deletion of glutaminyl residue beta 131 (H9) occurring in association with beta0-thalassemia, HbC, and HbS

A new unstable hemoglobin, Hb Leslie, has been observed in three generations of a Georgia family. The propositus, a 42-yr-old black veteran with hemolytic anemia and splenomegaly, has a hemoglobin variant with an electrophoretic mobility similar to that of hemoglobin F. The variant comprises about 85% of the total hemoglobin and was isolated by chromatography. Chemical analysis has identified the abnormality as a deletion of the glutaminyl residue in position 131 (H9) of the beta-chain. Deletion of this critical residue which participates in the alpha1beta1 contact causes decreased stability of the hemoglobin without significant changes in functional properties or morphologic abnormalities in the erythrocyte. Family studies revealed hemoglobin Leslie occurring in combination with beta0-thalassemia, HbS, and HbC. All persons with the various Hb Leslie combinations, including the propositus, have no clinical manifestations other than anemia. In some the anemia is fully compensated. There is no history of drug-associated hemolysis.

Hemoglobin Fort Gordon or alpha2beta2145 Tyr replaced by Asp, a new high-oxygen-affinity hemoglobin variant

Hemoglobin Fort Gordon, alpha2beta2145 Tyr replaced by Asp (HC2), has been observed in a 20-year-old black male with compensatory erythrocytosis. The variant was readily identified by electrophoresis and chromatography, and comprised about 30% of the red cell hemoglobin. The substitution was identified through analyses of tryptic peptides of various digests of the isolated beta chain. The oxygen affinity of whole blood was increased; two components were observed one of which had a greatly increased affinity for oxygen and a markedly reduced subunit cooperativity. It appears that the Tyr replaced by Asp substitution resembles the Tyr replaced by His substitution in hemoglobin Bethesda (Bunn, H. F. et al. (1972) J. Clin. Invest. 51, 2299-2309; Olson, J. S. and Gibson, G. H. (1972) J Biol. Chem. 247, 3662-3670; Adamson et al. (1972) J. Clin. Invest. 51, 2883-2888) in that both inhibit the quarternary change of the oxy to the deoxy conformation, resulting in greatly altered functional properties. Studies of a few members of the family were negative.