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The unique capabilities of the proton microprobe in an atmospheric environment as a biological tool are illustrated in studies of arsenic and mercury distributions in siingle strands of hair from poisoning victims and of the distributions of several abundant elements in frozen hydrated eye and kidney specimens from rats.

Using a double labeling indirect immunofluorescent technique, we studied the guinea pig trigeminal ganglion and eye for co-localization of substance P and calcitonin gene-related peptide. In the trigeminal ganglion, the number of neurons immunoreactive for calcitonin gene-related peptide significantly outnumber those immunoreactive for substance P, but virtually all substance P positive neurons are immunoreactive for calcitonin gene-related peptide. In the eye, a complex pattern of co-localization is present; both peptides co-localize in most immunoreactive nerve fibers. Nerve fibers immunoreactive only for calcitonin gene-related peptide tend to be concentrated in the cornea and posterior ciliary body. Nerve fibers immunoreactive only for substance P are present in relation to both iris muscles. Sensory denervation by intracranial transection of the ophthalmic and maxillary nerves fails to eliminate these substance P positive but CGRP negative iris nerve fibers. These findings indicate an alternative origin for substance P immunoreactive nerves supplying the iris muscles in this species.

Histamine (HI) is present in various structures of the bovine and rabbit eye (retina, choroid, sclera) and in the optic nerve of both species. The amine levels in particular structures of either cow or rabbit are highly differentiated, as well as profile of HI distribution which differs markedly between both species, except only the retina structure (HI levels were between 70-80 ng per g tissue). In the bovine retina HI is stored in non mast cell compartment, while in the optic nerve at least 50% of the amine is of mast cell origin. Approximately 90% of the retinal HI was recovered in the P1 subcellular fraction. HI in the bovine retina is metabolized by methylation. The data are discussed in terms of a possible physiological role of HI in the retina.

A comparative investigation of the distribution of monoaminergic neurons in non-malacostracan crustaceans was performed with the histochemical fluorescence method of Falck-Hillarp. Two fluorophores were found: the more widespread of the two emits a green fluorescence; and the more sparsely distributed emits a yellow to brown-yellow fluorescence. Specific green fluorescent areas were shown to exist in the protocerebrum. The central body and the optic ganglia of the compound eye (where present) are always fluorescent. Moreover, the centre of the nauplius eye may have a green fluorophore, as in ostracods, and a neuropile area, here called the frontal area. These neuropile centres are known from ordinary histological studies of the nervous system. In addition, there are specific monoaminergic centres, such as the so-called dorsal area of phyllopods and anostracans as well as the copepod specific areas. Specific monoaminergic areas appear in the deutocerebrum and the suboesophageal ganglion where they are particularly well developed. Presumed sensory neurons in the cavity receptor organ of Artemia saliva are shown to be monoaminergic. Monoaminergic sensory neurons have not been described previously in Arthropods. Presumed motor innervation of hind-gut and trunk muscles is also found, and it is concluded that in crustaceans neurons of every type (sensory, internuncial, motor) may be monoaminergic.

Biochemical analyses of subretinal fluid revealed a consistently high ascorbate level in the subretinal fluid of patients with rhegmatogenous retinal detachment. The average values and SDs of ascorbate in anterior chamber aqueous humor, subretinal fluid, and blood were 14.7 +/- 1.8, 27.4 +/- 2.1, and 1.8 +/- 0.2 mg/dL, respectively. The ascorbate concentration in subretinal fluid was always higher than that in aqueous humor. The high ascorbate level in subretinal fluid led to the hypothesis that aqueous humor contributes to the formation of subretinal fluid. Presumably and constant absorption of subretinal fluid by the choroid directs a portion of the aqueous humor from the posterior chamber into the subretinal space. The posterior movement of aqueous humor causes reduced ascorbate concentration in the anterior chamber and relative hypotony of eyes with rhegmatogenous retinal detachment. Closing the retinal break results in an interruption of the posterior movement of aqueous humor and rapid absorption of the remaining subretinal fluid by the choroid.

Rhodopsin- and vitamin A-immunoreactive sites were studied in the pineal organ of the larval and adult brook lamprey (Lampetra planeri Bloch), as well as in the retina of the larval lateral eye, at the electron microscopic level. In the pineal organ, several types of photoreceptor cells could be distinguished by their morphology and the immunoreactivity of their outer segments. The different kinds of photoreceptor cells were located at different levels of the pineal organ according to their distance from the "pineal window". The most superficial level, the so-called pellucida, appears to represent an exclusively "cone-type" area containing slender, rhodopsin-immunonegative (UV-blue-sensitive?) photoreceptors only. The second level, the pineal retina, contained predominantly rod-type photoreceptors, i.e., large, strongly rhodopsin-immunopositive (green-sensitive) photoreceptors medially, and few, small, weakly rhodopsin-immunopositive (blue-green-sensitive?) cells bilaterally. At the deepest level, the pineal atrium, there were both rod- and cone-type photoreceptor cells, the latter possibly representing red-sensitive elements. Vitamin A immunoreactivity was found in the outer segments of the pineal photoreceptor cells, in the cytoplasm and mitochondria of inner segments and perikarya, as well as in nuclear euchromatin and compact nucleoli. A similar gold labelling of organelles was observed in the ependyma and pineal neurons. The vitamin A immunoreaction of the outer segments suggests retinoids are present as chromophores of the photopigments. In the peripheral retina of the larval lateral eye, vitamin A immunoreactivity was found in some organelles of the undifferentiated photoreceptor cells, neurons, pigment epithelium and Müllerian cells. The localization of immunoreactive vitamin A in nuclei, nucleoli and cytoplasm including mitochondria appears to strengthen the case for an interaction of retinoids in the function of these organelles.

cAMP and cGMP contents were studied in various eye tissues of rabbits with experimental glaucoma induced by chronic intravenous adrenaline administration. Cyclic nucleotide level was measured in the retina, choroid, iris and ciliary body. An increase in the tissue cAMP level was found especially in the iris and ciliary body. An increase in tissue cAMP content is explained by an enhanced beta-adrenergic regulation in the eyes of rabbits with experimental glaucoma. No consistent changes were found in cGMP content in eye tissues.

The Proteus anguinus L. is a blind cave perennibranch amphibian whose visual system undergoes an important morphogenetic degeneration in adulthood. The eyeball becomes atrophied and disappears under the fat tissue of the head. However, a retina can still be identified and a photophobic behavior of the animal indicates a remaining photosensitivity. In the oldest animal observed, some photoreceptor cells are still present as well as other types of retinal neurons. Characteristic synapses are observed in both the inner and outer plexiform layers. Dopaminergic amacrine cells, with processes in the inner plexiform layer, can be identified by their tyrosine-hydroxylase immunoreactivity. Taken together, these results indicate a possible functional role of the remaining retina. Since dopamine is especially involved in light adaptation from darkness, the residual retina could act in triggering the turning behavior of Proteus in response to lightening.

Levels of acetylcholine (ACh) sensitivity and numbers of alpha-bungarotoxin (alpha-Bgt)-binding sites have been measured for chick ciliary ganglion neurons grown in cell culture under various conditions. The two properties were found not to change in parallel. Neurons maintained in culture medium supplemented with embryonic eye extract developed high levels of ACh sensitivity and low numbers of alpha-Bgt-binding sites, whereas neurons grown in medium containing elevated K+ concentrations displayed the reverse. Neurons from media containing both eye extract and elevated K+ concentrations had both low levels of sensitivity and low numbers of toxin sites. The growth conditions do not alter the basic binding properties of the ACh receptors and alpha-Bgt-binding sites. Both the ACh receptor dose-response characteristics and the pharmacological properties of the toxin-binding sites were similar for neurons grown in media containing eye extract or elevated K+ concentrations. The inhibitory effects of eye extract on development of alpha-Bgt-binding sites appeared to be specific: eye extract had previously been shown to stimulate neuronal growth and cholinergic development, and in the present study eye extract enhanced development of ACh sensitivity and had no effect on mechanisms responsible for binding and accumulation of tetanus toxin. Eye extract did not block alpha-Bgt binding in competition binding experiments and did not cause redistribution of toxin sites away from the neuronal soma. These results demonstrate that ACh sensitivity and alpha-Bgt-binding sites can be independently regulated on the neurons and suggest that the two membrane properties are associated with separate membrane components.

Investigations were carried out to determine whether the melanin present in the blue and brown eyes were eumelanin, the melanin present in black hair and dark skin, or pheomelanin, the melanin present in red hair and the skin of people with red hair. Our results showed that UV-visible irradiation of blue or brown eye melanin did not produce any superoxide. Irradiation of 51Cr-labelled Ehrlich ascites carcinoma cells in the presence of blue or brown eye melanin did not produce significant cell lysis. The electron spin resonance (ESR) signals of blue and brown eye melanins were very similar to those of eumelanin. Comparison of these findings with our previous results indicated that the blue and brown eye melanins are essentially eumelanin. The ESR signals further suggested that in the case of both blue and brown eye melanins the iris, ciliary body, choroid, and retinal pigment epithelium did not differ.

The content of the fibronectin, an extracellular glycoprotein in the drainage outflow system of human eyes was determined by the indirect immunoperoxidase staining technique. The degree of fibronectin accumulation in ocular tissues was evaluated by quantitative morphometric analysis. It was shown that the fibronectin level was elevated in ageing. Increased deposit of fibronectin in trabecular tissues, mainly, in the inner wall of Schlemm's canal and juxta-canalicular zone was demonstrated along with ageing. Comparison of fibronectin accumulation in glaucoma and ageing support the idea that ageing is a risk factor of glaucoma.

Angiotensin II (A2) is a vasoconstrictor generated by the renin-angiotensin system. A2 appears to act also as an angiogenic factor. Recent evidence suggests that renin is synthesized at many tissue sites and may generate A2 locally. Local A2 may have important functions in the normal and diseased eye. We examined eight human eyes by immunostaining with an antibody to prorenin, the biosynthetic precursor of renin. In all eyes, prorenin staining was extensive in the pars plicata of the ciliary body suggesting that the ciliary body synthesizes renin and this renin may be part of an ocular A2 generating system.

The ability to demonstrate AMPS in the trabecular region in the normal eye of the Rhesus monkey was shown to be critically dependent upon technical variation. Staining the fixed specimen prior to dehydration and embedding permits the uniform demonstration of AMPS in the trabecular region of the Rhesus monkey and shows it to be hyaluronidase-sensitive. Electron microscopy using the modified technique shows the reaction products to be present within the trabecular band, the intertrabecular spaces, and the canal of Schlemm. More impressive distribution was seen in the basement membrane of trabecular endothelium intimately related to the cell wall and in the ground substance and basement membrane of the endothelium of the inner wall of the canal Schlemm. The technique is also successful in the human eye and suggests a greater abundance of trabecular AMPS in open-angle glaucoma.

An investigation was undertaken to expand the data base for elemental concentrations within eye tissues of different species. This report provides data on the distribution of calcium, copper, iron and zinc in human, dog, bovine, bird, amphibian and fish ocular tissues. The variation between different eyes of the same individual and different individuals was calculated for each metal. Elemental concentrations between the left and right eyes of an individual were usually closer in value than between two eyes of different individuals.

Characteristically stained polyacrylamide gels can be obtained by disk-electrophoresis in acid medium of several tissues of the bovine eye. The technique permits to prove different types of collagen in the eye, and allows the differentiation and identification of the tissues. By these results the different tissues of the eye can be divided into three groups. 1. Tissues showing two alpha collagen components in polyacrylamide gel (cornea, sclera, iris, ciliary body, anterior lens capsule, and the pigmented epithelium of the retina). 2. Tissues possessing one alpha component only (zonula fiber and vitreous body). 3. Tissues which show neither the alpha nor the beta and gamma component of collagen (lens nucleous and retina without pigmented epithelium).

The experimental studies performed on nonpigmented rat choroids and the review of the important literature covered in this thesis seem to justify the following statements: 1. Mast cells are present in the choroid in significant numbers. 2. Mast cell numbers vary considerably from one individual to another and from one location in the choroid to another. 3. The major concentration of mast cells in the uvea is in the posterior choroid. 4. The mast cells of the choroid have a preferential location along arterial vessels. 5. Choroidal mast cell population density apparently decreases with senescence. 6. Mast cell products are present in sufficient quantity to exert substantial effects on physiologic, immunologic, and inflammatory responses in the choroid. 7. Choroidal mast cell products are released with appropriate stimulation and share some properties with the connective-tissue mast cell. 8. Choroidal mast cell demonstrate enough differences to suggest that a local differentiation may be present and may represent a locally controlled modulating effect for choroidal physiologic, immunologic, and inflammatory reactions.

The primary objective of this study was to investigate the effect of several precorneal factors on the retention of liposomes in tears and their interaction with the corneal and conjunctival surfaces. It was found that adsorption of liposomes onto these surfaces was requisite to the ocular absorption of inulin. Over a range of 10 to 50 microliter, the availability of binding sites at the corneal and conjunctival surfaces rather than the size of the instilled volume controlled the extent of liposomal adsorption and ultimately availability of inulin to the intraocular tissues. The inulin liposomes were in facile association with the adsorptive surfaces, as evidenced by their low resistance to removal by rinsing the eye with saline and by the lack of sustained inulin concentrations in any of the ocular tissues studied. This property of liposomes, coupled with the slow rate (1% per hour) at which they released inulin, was responsible for the absence of inulin in the aqueous humor as late as 240 minutes post-dosing. It was concluded that, for liposomes to be effective in ocular drug delivery, they must show affinity for and be bound to the corneal surface and, in addition, must release their contents at optimal rates.

Zinc, cobalt and selenium concentrations were determined in tunics, vitreous and lens of the eyes of 17 infants who died during the neonatal period. Significantly higher concentrations of the measured elements were found in the vitreous. The tunics contained more zinc and cobalt than the lens, while the latter contained more selenium.

The main lacrimal gland and accessory lacrimal tissue from seven autopsy cases, lacrimal biopsy specimens from three patients, and conjunctival biopsy specimens from ten patients were examined for lactoferrin by an immunohistologic technique. Lactoferrin was identified and localized to acinar epithelial cells of both main and accessory lacrimal tissue. Lactoferrin was not found in conjunctival tissue except within conjunctival neutrophils. Other possible sources of human tear lactoferrin were considered, but we concluded from our data that the primary source of lactoferrin in normal human tears is the acinar epithelium of the main and accessory lacrimal glands.

Extracts from albino rat eyes and pancreas, bovine and sheep pineals and human placenta containing TRH-like immunoreactivity were chromatographed on silica-gel plates. Comparison of elution profiles for TRH-like immunoreactivity with that of TRH revealed the presence of substances other than TRH in these samples. Chromatography of TRH-like immunoreactivity obtained from Rana pipiens skin eluted in two solvent systems produced elution profiles identical with that of synthetic Pyroglu-His-Pro-NH2 consistent with reports that frog skin contains large quantities of TRH. Implications of these findings are discussed.

Rimicaris exoculata is a shrimp that swarms over high-temperature (350 degrees C) sulphide chimneys at Mid-Atlantic Ridge hydrothermal fields (3,600 m). This shrimp lacks an externally differentiated eye, having instead a pair of large organs within the cephalothorax immediately beneath the dorsal surface of the transparent carapace, connected by large nerve tracts to the supraesophageal ganglion. These organs contain a visual pigment with an absorption spectrum characteristic of rhodopsin. Ultrastructural evidence for degraded rhabdomeral material suggests the presence of photoreceptors. No image-forming optics are associated with the organs. We interpret these organs as being eyes adapted for detection of low-level illumination and suggest that they evolved in response to a source of radiation associated with the environment of hydrothermal vents.

This report consists of a retrospective clinical study of the effect of retinal detachment repair, specifically the encircling procedure, on induced spherical refractive error. The analyze the findings we include optical and supplementary clinical and in vitro studies of corneal curvature, axial length, and anteiror chamber depth. The results of each of these help confirm and are sufficient to explain the discoveries of the original clinical study.

The validity of the inert gas clearance method for measuring choroidal blood flow has recently been demonstrated by studying the diffusion of krypton in ocular tissue. In this study the diffusion coefficients of krypton in rabbit ocular tissue were calculated from measurements of the diffusion coefficients of xenon. The mean values for the diffusion coefficients of krypton obtained in this study were 1.6 X 10(-5), 0.76 X 10(-5), 0.80 X 10(-5), and 1.2 X 10(-5) cm.2 per second for the sclera, choroid, retina, and vitreous, respectively.

The conjunctival surfaces of ten patients with active, ocular cicatricial pemphigoid, three patients with drug-controlled ocular cicatricial pemphigoid, and six patients with normal conjunctivas were studied using scanning electron microscopy. A homogeneous granular sheet of amorphous mucin-like material was observed covering extensive areas of the conjunctiva in eight of ten patients with active ocular cicatricial pemphigoid. This sheet of amorphous material was absent on drug-controlled ocular cicatricial pemphigoid and normal conjunctival specimens. Our study demonstrates that patients with active ocular cicatricial pemphigoid possess ocular surface mucus that appears thicker and more continuous than normal ocular mucus when observed with scanning electron microscopy. This observation is in agreement with clinical observations of thick mucus strands in the inferior fornix of patients with active ocular cicatricial pemphigoid.

The presence of an acetylcholinesterase inhibitor in the compound eyes of adult Triatoma infestans was demonstrated. The inhibitory activity was localized in the ocular pigments separated by disc gel electrophoresis. The inhibitor was selective against insect acetylcholinesterase, reversible, noncompetitive and heart stable.

We examined the correlation between radioactive assay and trephine-discbioassay of penicillin G sodium, cefamandole nafate, and gentamicin sulfate in ocular tissues of pigmented rabbits after subconjuctival administration of antibiotic. We devised a technique whereby a single sample of tissue could be assayed by both methods. This was achieved by performing the bioassay first, then measuring the resudual radioactivity in the agar and specimens. The results of both methods were generally within 13%. An exception was gentamicin in iris and choroidretina, for which the bioassay result was strikingly less than the radioassay value. No such discrepancy was evident when similar studies were carried out with gentamicin in albino rabbits. This suggests that the phenomenon is due to tight binding of gentamicin by melanin-containing tissues. The trephine-disc bioassay provides an accurate measure of diffusible bioactive antibiotic in ocular tissues.

There is controversy regarding the origin of the pigment-containing epithelioid cells in the uvea of eyes with sympathetic ophthalmia. The results of the present immunocytochemical study demonstrating the presence of muramidase and S-100 protein in these cells, and the binding of peanut lectin by the pigment-containing cells support the interpretation that the pigment-containing epithelioid cells and giant cells are of monocytic (histiocytic) origin. Our study also emphasizes the diverse functional capacity of these epithelioid cells.

Retinoids in the compound eyes of insects in ten orders were extracted by the oxime method and analysed by HPLC. Four geometrical isomers (13-cis, 11-cis, 9-cis and all-trans) of syn and anti retinal oximes, and syn and anti 3-hydroxyretinal oximes were separated in a single analysis by a stepwise eluent condition. The amounts of the two isomers, syn 11-cis and syn all-trans, were quantified. 11-Cis 3-hydroxyretinal was detected in six orders: Lepidoptera, Diptera, Coleoptera, Neuroptera, Hemiptera and Odonata, and retinal and 3-hydroxyretinal were found together in the compound eyes of some species of Coleoptera and Odonata. We conclude that early in their phylogeny, insects had the ability to use 3-hydroxyretinal as the chromophore of visual pigment. Peaks corresponding to syn 9-cis and 13-cis 3-hydroxyretinal oximes were observed on the chromatogram of extracts from fly heads and compound eyes of cicadas. Retinol and 3-hydroxyretinol were also analysed and quantified relative to retinal and 3-hydroxyretinal. Larger amounts of the alcohols than the aldehydes were found in the compound eyes of butterflies, hornets, cicadas and grasshoppers, which are diurnal insects. 3-Dehydroretinal has not been detected in insects.

Bovine and human zonules were found to be composed of noncollagenous acidic glycoprotein with a high cysteine content, double that previously reported. In reduced zonular fractions the most prominent peptide had a molecular weight (MW) of approximately 70,000. Lesser quantities of 170,000, 50,000, and 35,000 dalton peptides were also present and a variable number of lower MW bands, depending upon the degree of reduction and denaturation. A fraction of bovine zonules soluble in low ionic strength buffers contained primarily a peptide of approximately 50,000 daltons, often present as a doublet. Amino acid and hexosamine content of these two fractions was consistent with the presence of at least two different glycoconjugates, one a proteoglycan. Carbohydrate analysis of whole zonules suggested that these glycoconjugates include a sialofucose-containing glycoprotein and a lesser quantity of xylose-containing proteoglycan. The amino acid profile and peptide content of the zonules resembled that of elastic tissue microfibrils, increasing further the possibility of a close relationship between these two fibrils.

In our experimental conditions, the positive Karli reaction in the microvilli of cells which seem to be visual and the localization of vitamin A in their area show that these cells are photosensitive.

The distribution of [14C]-clonidine in the eye after intravenous administration and injection into the external carotid arteries was studied in a comparative manner in anesthetized cats. The amount of clonidine accumulated in the eye after intraarterial administration by far exceeded that after intravenous application. In addition the pharmacological effects of clonidine obtained by these two routes of administration were investigated and analyzed. The decrease in intraocular pressure after intravenous administration appears to be much stronger than after intraarterial injection. Obviously, there exists no direct correlation between the clonidine concentration in the eye and the ocular hypotensive effect of this drug.

The concentration of radioactive phosphorus in uveal melanoma and normal parts of the eye was determined in vitro in 14 eyes. The eyes were enucleated after a positive 32P uptake test. Portions of the melanoma as well as normal choroid, retina, sclera, lens, and vitreous were analyzed. The 32P uptake test had been performed at various intervals after intravenous administration of 32P from 24 to 556 hr. The in vitro uptake of 32P was compared to cell type, tumor volume, time of testing, percent uptake measured clinically, and specific activity. The only positive correlation was between percent uptake measured clinically and 32P concentration (dpm/gm). A higher concentration of phosphorus in melanoma resulted when carrier-free 32P was used. A negative correlation existed between number of hours from injection to clinical measurement of percent uptake, although melanoma to normal choroid ratios did not change from 24 to 72 hr. No correlation was found between uptake and tumor volume. The sample was small; however, we saw no correlation between 32P uptake and degree of malignancy.

A polypeptide present in Drosophila eye homogenates was identified as opsin. This polypeptide pI 7.8, with Mr 39,000 is a retina-specific protein. It has the spectral characteristics of rhodopsin contained in the R1-6 photoreceptors and decreases in amount with vitamin A deprivation. It contains a chromophore derived from vitamin A and linked to the protein moiety by a Schiff base. Moreover, the polypeptide identified corresponds to a retina-specific polypeptide that was shown previously to undergo light-dependent phosphorylation in living flies. These results indicate that many properties of Drosophila rhodopsin do not differ significantly from those reported for rhodopsins of other organisms. However, the isoelectric point of Drosophila opsin is considerably more basic than those reported for vertebrate rhodopsins.

A question concerning cyclic nucleotide immunocytochemical localization has been how much nucleotide remains associated with the tissue section. To answer that question cryostat sections of goldfish eye and mouse spleen, liver and lung were mounted on microscope slides and air dried. Following fixation by a variety of procedures employing heat, paraformaldehyde, glutaraldehyde, acetone, or ethanol, the sections were exposed to buffer (20 microM NaHPO4, 154 microM NaCl, pH 6.1) for 4 hours. The tissues were then scraped from the slides into 0.4N Perchloric Acid and cAMP and cGMP extracted and measured. The results show that fractions of both nucleotides are retained during buffer exposure. However, the amount retained varied with the: i) neucleotide, ii) fixation procedure, and iii) tissue type. Cyclic GMP retention was consistently higher (20-70%) than cAMP (6-30%). Glutaraldehyde was consistently more efficient in fixing cAMP, while cGMP retention was more variable with different fixation procedures. Tissue variability is seen in the example that spleen and liver retained more cGmp (71.4 and 70.6% respectively) than lung and eye (22.8 and 37.7% respectively). Maximum nucleotide loss occured during the first 5-30 minutes of buffer exposure with no additional loss accuring after another 20 hours. Collectively, these results demonstrate that cyclic nucleotides are retained during immunocytochemical staining procedures but that the degree of retention is dependent on several variables.

Retinochrome is readily reduced by sodium borohydride into an N-retinyl protein that emits visible fluorescence upon irradiation with near-ultraviolet light. Rhodopsin is also converted to a similar fluorescent product, but only when denatured with formaldehyde before reduction. Based upon this difference, retinochrome was discriminated from rhodopsin on frozen sections. The distribution of these two photopigments in various photosensitive tissues was examined by means of epifluorescence microscopy. In the octopus retina (Octopus vulgaris), the yellow-green fluorescence of reduced retinochrome was observed in both the basal regions of the outer segments and throughout the inner segments of the visual cells, while the fluorescence of reduced rhodopsin was restricted to within the rhabdomal layer of the outer segments. In the squid parolfactory vesicles (Todarodes pacificus), rhodopsin was present in the central lumen, which contains the distal processes of the photoreceptor cells, while retinochrome was detected in the myeloid bodies scattered within the vesicular wall. In the slug retina (Limax flavus), rhodopsin was found in the microvilli, and retinochrome appeared to be concentrated in the photic vesicles of the visual cells.

We have isolated a minor phosphatidyl ethanolamine component from pancreas and a minor phosphatidyl choline component from retina, which were revealed by their separate thin-layer chromatographic properties on silica gel and aluminum oxide sheets, respectively. We have described in some detail a number of modifications in thin-layer chromatography methodology which enhances the opportunity for assessing the glycerophospholipid and neutral lipid composition of tissues, as attested by a diverse set of examples, and have pointed out some of the associated technical problems.

The present study involves the intracardial injection of iodinated ovine prolactin into albino rats and the autoradiographic demonstration of patterns of isotopic incorporation into ocular tissues, including the retina, choroid coat and ciliary body. Control procedures include the utilization of competitive hormonal binding, a comparison of the radioactive pattern in eyes after the injection of iodinated beef serum albumen and an autoradiographic evaluation of the thyroid glands of all groups. The competitive uptake of iodinated prolactin into ocular tissues also was examined by liquid scintillation spectrometry. In normal rats, radioactivity was localized over the cells of the choroid coat and ciliary body of all groups receiving iodinated prolactin. The inner segments of the photoreceptors were radioactive in rats at 15 min after injection, but were unlabeled at only 5 min after injection.