Digital indocyanine green videoangiography of central serous chorioretinopathy

BACKGROUND

The pathogenesis of central serous chorioretinopathy (CSC) is poorly understood. Abnormalities in the choroidal circulation have been hypothesized to be causative factors. Fluorescein angiography has not been particularly useful in identifying specific choroidal defects in CSC, largely because of inherent limitations in imaging with this technique. Recent technologic advances in digital indocyanine green videoangiography allow enhanced imaging of the choroid and other subretinal structures in comparison with fluorescein angiography.

METHODS

We performed digital indocyanine green videoangiography in 29 consecutive eyes with CSC and compared our results with clinical and fluorescein angiographic findings.

RESULTS

Several newly recognized subretinal abnormalities in CSC were noted with digital indocyanine green videoangiography, including (1) presumed hyperpermeability of the choroidal circulation surrounding active retinal pigment epithelial leaks, (2) additional focal and multifocal areas of presumed choroidal hyperpermeability not associated with abnormalities detectable by fluorescein angiography or clinical examination, and (3) multiple presumed "occult" serous retinal pigment epithelial detachments with a characteristic indocyanine green videoangiographic pattern.

CONCLUSION

We suggest that the pathogenesis of CSC may be due to a choroidal vascular hyperpermeability with and without associated active pigment epithelial leaks and multiple presumed "occult" serous retinal pigment epithelial detachments. Based on these findings, a hypothetical model can be constructed related to the pathogenesis of CSC, beginning with choroidal abnormalities that secondarily affect the retinal pigment epithelium and neurosensory retina.

Intestinal expression of human apolipoprotein A-IV in transgenic mice fails to influence dietary lipid absorption or feeding behavior

Two transgenic mouse lines, expressing low or high amounts of human apo A-IV were created. In low and high expressor HuAIVTg mice on a chow diet, serum human apo A-IV levels were 6 and 25 times the normal human level and on a high fat diet, they were 12 and 77 times higher. Human apo A-IV was equally distributed between lipoprotein (mainly HDL) and lipid-free fractions. Intestinal absorption of radiolabeled cholesterol and triglycerides was unaffected in HuAIVTg mice. Vitamin A, carried exclusively in chylomicrons and their remnants, was catabolized normally. When an intragastric vitamin E bolus is given to the HuAIVTg mice, the initial absorption and appearance in triglyceride-rich lipoproteins was similar to that observed in normal mice. However, elevated amounts of vitamin E were subsequently observed in the VLDL of the HuAIVTg mice. Furthermore, in the fed state, serum VLDL triglycerides were markedly elevated in HuAIVTg mice. This effect was greater in high expressor mice. Serum total cholesterol was not elevated, but the distribution was altered in the HuAIVTg mice; VLDL-C was increased at the expense of VLDL-C. Kinetic studies suggested a delayed clearance of VLDL in HuAIVTg mice. Apo A-IV has been suggested to be a satiety factor, but no effect on feeding behavior or weight gain was observed in these HuAIVTg mice. In summary, our studies with HuAIVTg mice show that additional apo A-IV does not effect intestinal absorption of fat and fat-soluble vitamins, and at least chronic elevation of plasma apo A-IV does not effect feeding behavior in this model system.

Influence of corneal shape on limbal light focusing

PURPOSE

Light incident at the temporal cornea is focused by the peripheral anterior eye to the nasal limbus, the usual site of pterygium formation. Parameters that may contribute to observed individual variations in the degree of limbal light focusing were assessed.

METHODS

Computer-assisted optical ray tracing techniques were applied to a human anterior segment model. The angle of incident light (theta, 95 degrees to 108 degrees posterior to the sagittal plane), corneal central radius of curvature (ro, 7.2 to 8.4 mm), and shape factor (p) were varied, and the effect on distal limbal intensity (I) was calculated.

RESULTS

The magnitude of intensity peaks (Ipeak) is dependent on theta and ro. Steeper corneas have higher intensity peaks (Ipeak approximately 21.5X at ro = 7.2 mm, p = 0.75), and flatter corneas have lower intensity peaks (Ipeak approximately 8X at ro = 8.4 mm, p = 0.75) (cf Ipeak approximately 14X for a standard cornea, ro = 7.8 mm, p = 0.75). Anteroposterior location of intensity peaks is dependent on theta and ro. Steeper corneas have intensity peaks situated more anteriorly, whereas flatter corneas have more posteriorly placed peaks. Distal light distribution profiles demonstrate that intensity peaks are not always centrally located. At lower angles of incidence (theta = 100 degrees, ro = 7.8 mm, p = 0.75), peak intensity is located approximately 1 mm above and below the horizontal plane. The overall distribution (envelope) of light at the distal limbus is apparently independent of corneal shape.

CONCLUSIONS

Differences in corneal topography can account for the clinical observation of individual variation in the degree of limbal light focusing. Whether individuals with corneas capable of developing intense limbal foci may be more predisposed to developing pterygium requires further study.

[Color duplex ultrasound. A new procedure in the study of orbital blood vessels in diabetic retinopathy]

Color Doppler imaging is a new noninvasive technique that allows the measurement of flow velocity in small orbital vessels (both arteries and veins). We compared 59 eyes with proliferative, 47 eyes with nonproliferative and 24 eyes with preproliferative diabetic fundus changes with a control group of non-diabetic patients. The central retinal artery, short ciliary artery and ophthalmic artery of each patient were examined. The systolic, diastolic and mean velocity was obtained for each vessel. Differences between the groups were most prominent in the central retinal artery. The perfusion velocity was significantly lower (P < 0.01) in proliferative eyes (Vsyst 5.7 +/- 1.9 cm/s) than in the control group (Vsyst 9.4 +/- 1.4 cm/s) or the nonproliferative eyes (Vsyst 8.3 +/- 1.9 cm/s). In the preproliferative group the velocity distribution varied widely. Consequently, no statistically significant difference could be deduced in relation to either the control group or the group with proliferative diabetic changes. In the ophthalmic artery and ciliary artery no group showed significant differences from normal. Our measurements indicate a definite correlation between the severity of diabetic retinopathy and a decreased flow velocity, particularly in the central retinal artery. Thus, color Doppler imaging may help to identify those diabetic patients who are at high risk of developing severe diabetic retinopathy so that early photocoagulation treatment can be initiated.

Analysis of the IgG subclass distribution and inflammatory infiltrates in patients with anti-Hu-associated paraneoplastic encephalomyelitis

Using immunohistochemistry, we studied the IgG subclass distribution of the anti-Hu antibody in serum, nervous system, and tumor of patients with anti-Hu-associated paraneoplastic encephalomyelitis/sensory neuropathy (PEM/PSN). The nervous system was also examined for deposits of complement and the distribution and type of inflammatory cells. IgG1 and IgG3 were the predominant isotypes of the anti-Hu IgG in serum, nervous system, and tumor. A few patients also had anti-Hu IgG2, but this isotype was not consistently present in all the regions of the nervous system studied. There was no correlation between neurologic symptoms and specific anti-Hu isotype, nor was there evidence that different anti-Hu isotypes recognized specific brain regions. Although IgG1 and IgG3 can activate complement, only weak complement reactivity was found, and that only in a few areas of the nervous system. This finding, in addition to the absence of natural killer (NK) cells, suggested that complement-mediated toxicity and antibody-dependent cell cytotoxicity mediated by NK cells are not pathogenic in PEM/PSN. Inflammatory infiltrates included CD19+ (B cells) and CD4+ (helper/inducer) cells in the perivascular spaces, and lymphocytes bearing CD8+CD11b- markers (cytotoxic T cells) in the interstitial spaces. Infiltrates of EBM11+ (monocyte/macrophage) cells were identified in the perivascular spaces (macrophage phenotype) and in those interstitial regions (microglial phenotype) with severe pathologic changes. The ability of the IgG1 and IgG3 isotypes to bind Fc receptors may have played a role in the recruitment of these monocyte/macrophage cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Opioid receptor density changes in Alzheimer amygdala and putamen

Since opioids can influence the release of acetylcholine, substance P and a number of other neurotransmitters that have been implicated in the pathogenesis of Alzheimer's disease (AD), it is of interest to assess opioid receptor levels in AD. We have examined mu, delta and kappa opioid receptor binding parameters, binding sensitivity to a GTP analog and distribution in amygdala, frontal cortex and putamen of AD brain. Control brains were matched according to age, sex, post-mortem interval and storage time. Kd values and GTP analog binding sensitivity did not differ in AD and control brains. Bmax values for mu ([3H]DAMGE) sites also appeared unaffected by in vitro binding assays. In contrast, kappa ([3H]U69593) and delta ([3H]DSLET) opioid receptor levels, were significantly changed. In AD amygdala kappa Bmax values increased from control levels of 123 +/- 12 to 168 +/- 13 fmol/mg protein, whereas densities of kappa and delta sites were decreased from 94 +/- 8 to 48 +/- 8 and 102 +/- 3.6 to 69 +/- 8.5 fmol/mg protein, respectively, in putamen. Autoradiography revealed corresponding differences in the distribution of kappa opioid receptors. The findings indicate that the kappa binding site, which is quantitatively the major opioid receptor class in human brain, undergoes marked changes in AD amygdala and putamen.

Novel opioid binding sites associated with nuclei of NG108-15 neurohybrid cells

Nuclear opioid binding sites have been discovered in NG108-15 neurohybrid cells. Marker enzyme analyses as well as electron and fluorescence microscopy studies attested to the high degree of purity of the nuclear preparations. Immunohistochemical studies on cryostat sections of NG108-15 cells with an antibody to the opioid receptor corroborated a nuclear localization. 3H-[D-Pen2,D-Pen5]enkephalin (3H-DPDPE), 3H-[D-Ala2,D-Leu5]enkephalin (3H-DADLE), and 3H-diprenorphine binding parameters, Kd and Bmax values, and heterologous competition binding and stereospecificity data satisfied criteria for the presence of delta-opioid sites in purified nuclear preparations. Neither mu-([D-Ala2,mephe4,gly-ol5] enkephalin), dihydromorphine, nor kappa-(U69593) specific binding was detectable in purified nuclear preparations. Rates of association and dissociation of 3H-[D-Ser2,L-Leu5]enkephalyl-Thr were comparable to values obtained previously for opioid receptors. Opioid binding was also shown in subnuclear preparations from NG108-15 cell cultures. Agonists, 3H-DADLE and 3H-DPDPE, bind with high affinity to nuclear membranes and with lower affinity to chromatin. In contrast, partial agonist 3H-diprenorphine high-affinity binding sites were predominant in chromatin, while low-affinity binding was found in the nuclear membrane. Accordingly, 5'-guanylylimidodiphosphate sensitivity of 3H-DADLE binding was detected in nuclear membranes but not in chromatin. Both agonist and partial agonist opioid binding to nuclear membrane and chromatin were abolished upon cycloheximide treatment of NG108-15 cells. Taken together, the results suggest that NG108-15 cells contain newly synthesized GTP binding regulatory protein (G-protein)-coupled delta-opioid receptors in nuclear membranes and uncoupled opioid binding sites in chromatin.

A successful pregnancy from the oocyte donation programme in Singapore General Hospital

A 41-year-old Chinese woman was seen in our centre in June 1989 with 5 years of premature menopause, requesting ovum donation. She was placed on cyclical hormonal therapy and put on the waiting list for ovum donation. Excess ova became available through one of our IVF patients and were fertilised with her husband's semen. Four pre-embryos resulted and these were cryopreserved using 1,2 propanediol. Embryo transfer in her second cycle of trying on 16 March 1990 of 2 pre-embryos was successful and a singleton pregnancy resulted. The pregnancy was supported with estradiol valerate and intramuscular progesterone till 17 weeks of gestation. The pregnancy went on uneventfully and she delivered a healthy baby boy by Caesarean section on 21 December 1990.

Less mortality but more relapses in experimental allergic encephalomyelitis in CD8-/- mice

Mice lacking in CD8 were generated from homologous recombination in embryonal stem cells at the CD8 locus and bred with the experimental allergic encephalomyelitis (EAE)-susceptible PL/JH-2u through four backcross generations to investigate the role of CD8+ T cells in this model of multiple sclerosis. The disease onset and susceptibility were similar to those of wild-type mice. However, the mutant mice had a milder acute EAE, reflected by fewer deaths, but more chronic EAE, reflected by a higher frequency of relapse. This suggests that CD8+ T lymphocytes may participate as both effectors and regulators in this animal model.

Conjunctival hyperaemia in non-contact lens wearers

Conjunctival hyperaemia was assessed in noncontact lens wearers using a photographic reference scale. The study was carried out on a sample of 252 females and 227 males within the age range of 1 to 89 years. The results show increasing levels of hyperaemia with age and higher levels of hyperaemia in males than in females. The differences in hyperaemia level for age and sex, however, were small and were insignificant clinically.

Peripheral light focusing by the anterior eye and the ophthalmohelioses

Peripheral focusing of light by the anterior eye may provide a unifying concept to explain the location and etiology of sun-related eye conditions (ophthalmohelioses). Using a bovine eye model, along with computer-assisted ray-tracing techniques to model limbal focusing, we demonstrated a correlation between the locations of the foci of scattered incident light (resulting in a 20-fold concentration of light at the limbus) and the usual locations of pterygium and cortical cataract. These findings suggest the need for improved ocular protective devices, particularly ones that provide lateral protection of the eye against the increased ultraviolet insolation resulting from thinning of the ozone layer.

Hypophosphatemic rickets with hypocalciuria following long-term treatment with aluminum-containing antacid

We present what we believe is the first case of rickets following prolonged treatment with aluminum containing antacids that bind phosphate, in an 18-year-old mentally retarded boy with cerebral palsy and spastic quadriplegia. As expected, serum calcitriol was increased and urinary phosphate excretion was very low. However, in contrast to all published cases of antacid induced hypophosphatemic osteomalacia in adults, despite a substantial increase in bone resorption reflected by urinary total hydroxyproline excretion, urinary calcium excretion was low rather than high, and significant hypocalcemia occurred after antacids were ceased and a phosphate salt administered. We suggest that the skeleton was so under-mineralized because of growth during prolonged phosphate deficiency, possibly augmented by anticonvulsant administration and immobilization, that increased bone resorption did not release enough calcium to cause hypercalciuria, or to prevent hypocalcemia during resumption of normal mineralization.

Geometrical ray-tracing: a 'ray free' method

A new geometrical method of determining the location of the image of an optical component is described. This method does not require rays to be drawn. It can be applied to refractive and reflective components as well as multi-component systems.

Early experience and the consumption of alcohol by adult C57BL/6J mice

Two types of early experience were examined for their effect on voluntary alcohol consumption by adult C57BL/6J mice: the experiences associated with belonging to a particular litter, and the experience of early postweaning choice between water and a 10% alcohol solution. Males from identified litters were individually caged from arrival at three weeks of age and given a choice between 10% alcohol and water when eight weeks old. Another group without notation of litter was given alcohol-water choice upon arrival at three weeks of age. Alcohol intake was examined by three measures: daily licks of 10% alcohol, alcohol selection (percent alcohol drinking), and volume of alcohol drunk daily. Belonging to a particular litter did affect body weight and growth, but had no effect on adult consumption of alcohol. Postweaning exposure to alcohol choice, however, produced a small but significant and prolonged increase in alcohol consumption by adults. Furthermore, a developmental trend was found in mice offered alcohol choice at an early age: alcohol preference developed as postweaning growth slowed.

Manipulation of alcohol preference in C57BL/6J mice by episodes of food poisoning

Individual differences in the amount of alcohol consumed in a choice situation are found in highly inbred C57BL/6J mice. The extent to which environmental stress can modify alcohol preference was studied by coupling acute episodes of poisoning with restricted fluid availability, and recovery with free choice of drinking fluids. Addition of actinomycin D, a mycotoxin, to ordinary chow during 2-day periods produced acute episodes of nonlethal food poisoning from which the mice recovered rapidly. Consumption of a 10% alcohol solution and of water was recorded for several weeks before poisoning and for several weeks after the last episode. By varying drinking fluids available to the mice during the episodes of poisoning, long-lasting changes in alcohol preference were produced. When 10% alcohol was the sole drinking fluid available during poisoning, preference for the alcohol solution was abolished. When water was the sole fluid during poisoning, alcohol preference was increased above the already high levels established in the baseline and above a control group that was restricted to water during the treatment periods but was not poisoned. This increased alcohol preference was due to a nearly complete suppression of water intake in the posttreatment period; there was no significant increase in amount of alcohol consumed. The greatest individual differences in subsequent alcohol preference were found in the group of mice which continued to have free choice of alcohol and water during episodes of poisoning. The variety of responses to the same treatment show how environmental influences outside the experimenter's control may account for the variability found in voluntary alcohol consumption among genetically homogeneous mice.

Toward an analogue of alcoholism in mice: analysis of nongenetic variance in consumption of alcohol

Drinking behavior of the isogenic mouse strain C57BL/6J was analyzed into nongenetic components: stochastic fluctuations, responses to fluctuations in the current environment, and persistent differences between individual animals. The latter accounted for the major part of the variance. The variance was neither increased by differences in diet during the postweaning rapid growth period (prior to assay for drinking choice) nor diminished by uniformity of treatment during this period, suggesting that significant differentiation had occurred prior to weaning. The large variance between animals could be explained by assuming that the genetic role in consumption of alcohol by C57BL mice is permissive--a relative insensitivity to the aversive orosensory and pharmacological effects of 10% alcohol--rather than a specific drug-seeking predisposition.

Circadian feeding and drinking patterns of genetically obese mice fed solid chow diet

Feeding and drinking were recorded in male ob/ob mice and lean mice fed pelleted Purina Lab Chow No. 5001 with water to drink. The circadian patterns of eating and drinking of obese mice differed from those of lean mice, in both the proportional temporal distributions of feeding and of drinking behavior across the 24-hour day and in the absolute amounts consumed hourly. The pattern of increased food consumption by the obese mice was different than that underlying increased water consumption. When meal parameters were analyzed in terms of 'complete meals' of both feeding and drinking (the end of a meal defined as at least 12 consecutive minutes with no ingestion), obese and lean mice had the same number of meals and their periodicity was similar, but meal size was much greater in the obese mice. In the dark, both obese and lean mice showed strong postprandial correlations of meal size with time from the start of a meal to start of the next meal.

Strategies for minimizing the ocular effects of extended contact lens wear--a statistical analysis

In a study reported recently, the effects of long-term extended wear of soft contact lenses on the human cornea were found to include epithelial thinning, a reduction in epithelial oxygen uptake, induction of epithelial microcysts, stromal thinning, and an increase in endothelial polymegathism. A multiple regression analysis was performed on data from this study to identify lens or patient characteristics associated with these effects. Although generalization to the population of conclusions based on associations identified using a small sample should be treated with caution, results from this analysis suggest that lens-induced effects on the cornea may be minimized by fitting lenses that are thinner and more mobile, and by encouraging more frequent lens removal and replacement. Patients with thinner corneas and with high endothelial cell density and low polymegathism before commencing lens wear tended to show fewer effects from extended lens wear.

Skeletal abnormalities of acrogeria, a progeroid syndrome

We report the skeletal abnormalities in a 4 1/2-year-old boy with acrogeria, a progeroid syndrome of premature aging of the skin without the involvement of internal organs seen in Hutchinson-Gilford progeria syndrome. Acro-osteolysis of the distal phalanges, delayed cranial suture closure with wormian bones, linear lucent defects of the metaphyses, and antegonial notching of the mandible are the predominant skeletal features of the disorder. The skeletal features described in 21 other reported cases of acrogeria are summarized.

Responses to a dry eye questionnaire from a normal population

A dry eye questionnaire was completed by 500 patients who presented for the correction of refractive error. A sample of non-contact lens wearers was extracted (N = 177) and responses were compared between males and females, and between three subgroups according to age. Females responded at a significantly higher rate in regard to 4 of 24 questionnaire segments. Differences according to age were found for 5 of 24 questionnaire segments. Except for the question concerning arthritis, increased prevalence of dry eye findings in over-45-year-old females was not found in this normal population. These results, combined with those reported previously, validate the use of the questionnaire as a screening instrument that will enable ocular sicca cases to be identified.

Cartilage proteoglycan changes in experimental canine osteoarthritis

Articular cartilage contains at least 2 proteoglycans (PGs) which aggregate with hyaluronate: one larger, richer in chondroitin sulphate (CSRPG); the other smaller, relatively richer in keratan sulphate (KSRPG). With maturation the ratio of CSRPG/KSRPG decreases. In order to test the hypothesis that osteoarthritic cartilage contains an increased amount of proteoglycans characteristic of immature cartilage, experimental osteoarthritis (OA) was induced in 11 dogs by transection of the anterior cruciate ligament. Proteoglycan populations were assessed by composite agarose polyacrylamide gel electrophoresis (CAPAGE). The OA cartilage had more proteoglycan and an increased proportion of the slower migrating band on CAPAGE, which corresponds to the CSRPG, supporting the hypothesis that OA cartilage contains an increased amount of proteoglycans characteristic of immature cartilage.