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Homeotic genes comprising the ABCE classes partly detail the genetic networks that control aspects of floral organ initiation, development, and architecture, but less is known about how these gene functions are translated into changes at the cellular level in growth and cellular differentiation that are involved in the formation of diverse floral organs with specific shapes and sizes. Hormones are the principal transducers of genetic information, and due to recent advances in understanding hormone function in floral development, it is timely to review some of these findings. Flower development is the result of a regulated balance between meristem size and coordination and organ initiation. Floral meristem size is regulated by cytokinin, gibberellin, and auxin, and auxin plays a major role in organ initiation and organogenesis. How hormones contribute to the development of each organ is partly known, with stamen development reliant on almost all hormones, petal development is affected by gibberellins, auxin, and jasmonic acid, and gynoecium development is predominantly regulated by auxin. Furthermore, the interconnections between genetic hierarchies and hormones are being elucidated, and as almost all hormone groups are implicated in floral development, points of hormone crosstalk are being revealed.

Two-year-old Sitka spruce (Picea sitchensis (Bong.) Carr.) seedlings were subjected to nitrogen (N) deficiency for 1 year and then treated twice weekly with N fertilizer solutions (0 to 224 mg N 1-1) for 20 weeks. Needle growth in terms of projected area and cell number, and photosynthesis in terms of pigment concentration, net photosynthetic rate (PN), stomatal conductance to CO2 (Gs) and intercellular partial pressure of CO2 (Ci) were measured. Nitrogen deficiency caused significant reductions in needle size and needle number per shoot. Refertilization caused free growth, and increases in size and cell number of needles arising from primordia initiated during N deficiency. Nitrogen concentration did not affect mean cell size, indicating that N nutrition determined needle size through cell division and not cell expansion, and that favorable N supply during needle expansion was more important in determining final needle size than limitations imposed on the primordia during the N deficiency pretreatment. Nitrogen deficiency caused reductions in chlorophyll and carotenoid concentrations, PN and Gs, and an increase in Ci. Refertilization caused a reversal of these changes, and the magnitude of the responses increased with increasing N supply. The large increases in many of the measured parameters in response to the small amounts of added N suggest that young Sitka spruce trees respond positively to N supply and are tolerant of all but severe N deficiency.

Immunohistochemistry and in vitro autoradiographic techniques were used to investigate the localization of endothelin (ET)-like immunoreactivity and [ 125 I]ET-1 binding sites in sections of ocular tissues of normal rabbits. ET-like immunoreactivity was localized to the corneal endothelium and the pre-epithelial layer of the cornea, which was specifically inhibited by addition of exogenous ET-I. Immunoreactivity for ET was also observed in the retinal ganglion layer and periocular fat tissues. These, however, were not inhibited in the presence of ET-1. Autoradiography showed binding sites for ET-1 in the iris and ciliary body. Emulsion-dipped slides of sections of rabbit eyes incubated with [ 125 I]ET-1 showed specific labeling for binding sites over structures that were identified from serial sections stained with hematoxylineosin. These were the anterior stroma of the iris root, the walls of capillaries, the circular arteries, and the veins of the ciliary body and extraocular muscles. No binding sites were found in the cornea or conjunctiva. The difference in regional distributions of ET storage and binding sites in rabbit ocular tissue suggests that the peptide may have specific physiologic functions.

SUMMARY Growth and photosynthetic development were measured for currently developing needles of young trees of Sitka spruce [Picea sitchensis (Bong.) Carr.] throughout their fourth growth season. Treatments included trees that were fully fertilized (control), trees deficient in phosphorus (–P), or nitrogen (–N), and trees initially deficient but then supplied with phosphorus (–PR) or nitrogen (–NR). Growth was measured in terms of needle projected area, and the photosynthetic components measured were pigment concentration, net photosynthetic rate, (PN), activity of ribulose-1,5-bisphosphate carboxylase, (RuBPC), stomatal conductance to CO2, (Gs), and the intercellular partial pressure of CO2, (Ci). Needle growth was rapid, beginning in early May and being complete by the end of the month or early in June. Free growth occurred in the –NR treatment. Photosynthesis increased throughout the season, reaching a peak in August, with some variables subsequently showing a decrease in value. PN increased more rapidly during needle expansion than either chlorophyll concentration or RuBPC activity. Phosphorus deficiency led to a reduction in RuBPC activity, which was restored to the control value following Refertilization with P. Nitrogen deficiency severely reduced values of all variables studied, except Ci, which was higher than for the controls. Refertilization of –N trees caused a very rapid increase in values of all variables, with an increase in Ci, representing a larger increase in mesophyll conductance to CO2, (GM), than GS, PN and RuBPC activity were significantly correlated with total chlorophyll concentration for all treatments, but PN was not correlated with GS or RuBPC activity.

The cotyledon represents one of the bases of classification within the plant kingdom, providing the name-giving difference between dicotyledonous and monocotyledonous plants. It is also a fundamental organ and there have been many reports of cotyledon mutants in many species. The use of these mutants where they have arisen in Arabidopsis has allowed us to unravel some of the complexities of embryonic patterning and cotyledon development with a high degree of resolution. The cloning of genes involved in cotyledon development from other species, together with physiological work, has supported the hypothesis that there exists a small number of orthologous gene hierarchies, particularly those involving auxin. The time is therefore appropriate for a summary of the regulation of cotyledon development gleaned from cotyledon mutants and regulatory pathways in the model species Arabidopsis and what can be inferred from cotyledon mutants in other species. There is an enormous variation in cotyledon form and development throughout the plant kingdom and this review focuses on debates about the phylogenetic relationship between mono- and dicotyledony, discusses gymnosperm cotyledon development and pleiocotyly in natural populations, and explores the limits of homology between cotyledons and leaves.

Needle development and shoot growth were studied in 14- and 20-year-old Sitka spruce (Picea sitchensis (Bong.) Carr.) planted on an oligotrophic peat and fertilized with N, P and K (control), N and P (-K), N and K (-P) or unfertilized (-NPK). Shoot extension, needle number, and the size and number of needle cells were observed throughout the season. Beginning with bud burst in early May, needle growth continued for nine weeks in the control treatment. Needle growth in the mineral deficiency treatments terminated at the same time as in the controls, although it did not begin until up to three weeks later than in the control trees. Needles developed acropetally along the shoot, with basal needles completing their development first. Cell division in needles of control trees lasted about 3 weeks, with cell expansion continuing for a further 3 weeks. Initial mean cell cycle times were shortest for proximal needles following bud burst, but lengthened as the season progressed. Cell number increased from 6600 in the primordia to 200 000 in mature needles. Final needle dimensions and cell number varied according to the position of the needle on the shoot. The largest needles with the most cells were near the middle of the shoot. Relative to the controls, all mineral deficiency treatments reduced shoot length, bud and needle dimensions, and needle cell number, particularly the -P treatment. Potassium and P deficiency treatments reduced primordial cell number by up to 42%, whereas final mean cell size was 30% greater in the -P treatment, 17% greater in the -NPK treatment, but 14% smaller in the -K treatment. Mean cell size was constant for needles at all positions in any particular treatment at any time, so that final needle size was determined by cell number alone. Needle dry weight/fresh weight ratio continued to increase until early August, with significantly higher ratios in the -K and -P treatments than in the controls.

We wanted to determine whether topical polyhexamethylene biguanide (PHMB) 0.02% was effective in the treatment of experimental Fusarium keratomycosis in rabbits.Fusarium solani keratomycosis was induced in the eyes of 12 New Zealand white rabbits. The rabbits were treated with PHMB 0.02% in one eye and placebo in the other eye for 6 days. The rabbits were evaluated in a masked fashion using a standardized system for clinical progression of the disease. Then the corneas were trephined and growth of F. solani in colony-forming units per milliliter (CFU/ml) determined.Clinical evaluation demonstrated no significant mean difference (p0.10) in clinical scores between treated and control eyes on day 6 (0.583 +/- 2.503). There was a significant mean CFU difference (p = 0.06) between treated eyes and control eyes (182.5 +/- 314.44). Seven of 12 eyes (58%) in the PHMB group exhibited no growth, whereas two of 12 (17%) eyes reported no growth in the control group. One of 12 eyes (8%) reported100 CFU in the PHMB group, whereas seven of 12 eyes (58%) reported100 CFU in the control group.PHMB 0.02% was effective in significantly reducing the fungal growth in our rabbit model of Fusarium keratomycosis. The future role of PHMB in the treatment of Fusarium keratitis needs to be further evaluated.

Immunohistochemistry and in vitro autoradiographic techniques were used to investigate the localization of endothelin (ET)-like immunoreactivity and [125I]ET-1 binding sites in sections of ocular tissues of normal rabbits. ET-like immunoreactivity was localized to the corneal endothelium and the pre-epithelial layer of the cornea, which was specifically inhibited by addition of exogenous ET-1. Immunoreactivity for ET was also observed in the retinal ganglion layer and periocular fat tissues. These, however, were not inhibited in the presence of ET-1. Autoradiography showed binding sites for ET-1 in the iris and ciliary body. Emulsion-dipped slides of sections of rabbit eyes incubated with [125I]ET-1 showed specific labeling for binding sites over structures that were identified from serial sections stained with hematoxylineosin. These were the anterior stroma of the iris root, the walls of capillaries, the circular arteries, and the veins of the ciliary body and extraocular muscles. No binding sites were found in the cornea or conjunctiva. The difference in regional distributions of ET storage and binding sites in rabbit ocular tissue suggests that the peptide may have specific physiologic functions.

Infectious conjunctivitis of the newborn is caused by a wide variety of microorganisms. The ocular findings may be part of a widespread systemic infection. Clinical presentations are not diagnostic of the cause, and a microbiologic work-up with cytology, cultures, and microbial sensitivities is mandatory. The selection of specific antimicrobial therapy is based on the findings of laboratory studies. Prophylaxis with silver nitrate solution, 1.0% tetracycline, or 0.05% erythromycin ointment is effective for the prevention of gonococcal and chlamydial conjunctivitis in the newborn.

Intravitreal injection of interferon gamma (IFN-gamma) induces increased expression of Class II major histocompatibility complex (Ia) antigen expression on corneal endothelial cells and stromal fibroblasts. In contrast, IFN-gamma has no detectable effect on Ia antigen expression in epithelium. Induction of Ia antigen expression was rapid with increases detectable as early as 6-12 hours after a single injection of 1 x 10(5) units. Expression peaked at 24-48 hours and decreased to background levels by 120 hours. The Ia antigen expression increased in a dose-dependent manner, and IFN-gamma treatment also induced the synthesis of increased amounts of a 65-kilodalton (kD) protein in the cornea. Increased levels of this 65-kd protein are seen as early as 12 hours after treatment and can be induced with as little as 1 x 10(2) units of IFN-gamma. The function of the 65-kd protein is unknown. This model should be useful in studies on in vivo modulation of Ia antigen expression.

Critical factors of soft contact lens care include adequate disinfection and neutralization of the chemical constituents of the disinfecting system before reinsertion. Three cases of microbial keratitis are described that exemplify the critical nature of disinfection with adequate antimicrobial activity. Disinfection rates are described for a 3% solution of hydrogen peroxide (H2O2) against multiple microorganisms. The results indicate that H2O2 is equivalent to heat disinfection when used for appropriate lengths of time. Problems associated with chemical disinfection include lens fit alterations, which may lead to epithelial trauma. However, unless antimicrobial chemicals can be rinsed, neutralized, or degraded, they can also injure the corneal and conjunctival epithelium. Repeated exposure of the corneal epithelium to oxidizing agents renders it vulnerable to complications.

Previous studies have shown that Langerhans cells (LC) in normal human corneas differ from their counterparts in other epithelia (eg, skin, gingival, cervical) by their lack of the thymocyte antigen T6 on their membranes. In those studies only three out of four very young infant corneas (newborn, 3-day-, 8-day-old) have displayed positive T6 staining to date. Corneas from older infants and adults have demonstrated no such staining. This study tested the capacity of corneal LC to express T6 by in vitro induction with several immunomodulating agents. Human gamma interferon (IFN gamma was tested at 1000 U/ml, 500 U/ml and 100 U/ml. Interleukin-1 (IL-1) was tested at 100 U/ml, 50 U/ml and 20 U/ml. Thymopoietin pentapeptide (TP-5) was tested at 10 micrograms/ml, 1 micrograms/ml and 0.1 microgram/ml. Combinations of these agents were also tested in a similar fashion. None of these immunomodulating agents or combinations of them were able to induce T6 expression on normal corneal LC. This may reflect an innate incapacity of these cells to express this antigen or dosage requirements in excess of those tested.

An adult with cutaneous diphtheria was admitted with bilateral purulent conjunctivitis and a perforated eye with most of the cornea absent due to Corynebacterium diphtheriae. At the time of admission of grayish patch of corneal epithelium was noted in the other eye, and in the next 24 hours there developed a large corneal perforation with dissolution of much of the cornea. Involvement of the external eye in diphtheria is rare but it is usually associated with cutaneous forms of the disease. Cutaneous diphtheria has been prominent in several recent outbreaks in the United States. Prompt recognition, early antibiotic treatment, and neutralization of the toxin with antitoxin are required for successful therapy.

Thymidine kinase (TK) activity was examined in extracts of TK-deficient cells infected with low passage isolates of herpes simplex virus type 1 (HSV-1) obtained from patients with herpetic keratitis. TK activity induced by the virus, relative phosphorylation rates of thymidine and iododeoxyuridine (IUDR), and Km values for thymidine and for IUDR were compared for TK induced by the different viral isolates. Four of the five isolates showing IUDR resistance in vitro and in vivo also exhibited alterations in properties of the viral TK. Two induced very low levels of viral TK. Three (including one with reduced TK) had increased Km values for IUDR. A fifth IUDR-resistant isolate induced TK similar to the IUDR-sensitive isolates. The results indicate that modification of viral gene for TK may be responsible for development of clinical resistance to IUDR in many occurrences of herpetic keratitis.

The rapid development of suppurative reaction in response to a copper-containing intraocular foreign body disposes the eye to a poor prognosis. An intraocular brass foreign body case involving cornea, iris, lens, vitreous and retina was satisfactorily managed by early foreign body removal and corneal transplantation followed by scleral buckling for retinal detachment. Early intervention is advocated as alternative management with expectation of improvement in the prognosis for recovery of useful visual function.

An outbreak of unusual conjunctivitis occurred in Seattle in the summer of 1974. We found evidence of adenovirus type 19 (Ad19) infection in 28 of 42 (67%) referred cases from whom specimens for virus isolation and/or serology were obtained. Virus was isolated from conjunctiva, throats, and/or stools, often in week 2 of illness. Ad19-related cases more frequently had severe ocular pathology, transient visual impairment, and active disease for longer than a week. Secondary illnesses were more frequent in relation to Ad19 infection (26%) than to conjunctivitis of other etiology (5%, P less than 0.05). Persons with Ad19 infection commonly experienced sore throats without coughs or fevers. No common source of infection was identified in the outbreak, and illness was unrelated to occupation, residence, or family characteristics. A 3- to 8-day incubation period was suggested by two related cases.

Exchange penetrating keratoplasties were performed in NZW rabbits using conreas soaked in heterologous 'blocking' antibody (guinea pig anti-rabbit gamma-globulin) under various experimental situations and immunogenic stimuli. Results suggest that the antibody can protect the rabbit graft from weak rejection stimuli possibly by blocking the afferent arc of the immunologic reflex, but cannot protect the graft from presensitization, or nonocular sensitization. The use of a blocking antibody in human transplantation would be simple and of slight risk to a graft recipient.

An animal model has been developed to study the effects of various prophylaxis agents on acquisition of chlamydial conjunctivitis. When Hartley strain newborn guinea pigs received ocular inoculations of Chlamydia psittaci followed by the instillation of various agents, 1% AgNO3 significantly lowered the risk of developing chlamydial conjunctivitis if it was administered within 15 min after the inoculation with C. psittaci. However, if the AgNO3 was administered at either 1 hr or 2 hr following inoculation, it did not have any prophylactic effect on the development of chlamydial conjunctivitis. Erythromycin ointment, 0.5%, was also found to prevent chlamydial conjunctivitis. The prophylactic effect was similar to placebo when the drug was given at 15 min; however, erythromycin ointment prophylaxis 1 hr or 2 hr after inoculation with C. psittaci was statistically superior to placebo.

Nine normal adult and seven normal infant human corneas were studied for the presence of dendritic epithelial Langerhans cells in a masked fashion. Epithelial flatmounts were separated from the underlying corneal stroma using EDTA. The epithelial Langerhans cell densities were determined in the limbus as well as the peripheral, pericentral, and central corneal regions following staining with ATPase. Segments of the flatmounts were also studied by immunofluorescence to confirm that the dendritic cells contained class II histocompatibility antigens. The limbus, peripheral, and pericentral zones of adult and infant flatmounts contained similar densities of Langerhans cells. However, the central corneal Langerhans cell densities in infants were significantly elevated as compared with those in adults. These results suggest that Langerhans cells are a constant constituent of the human central corneal epithelium during late gestation and early infancy. They further suggest that perturbations of the corneal epithelium are not required for the presence of Langerhans cells in the corneal epithelium.

Isolates were obtained from 10 patients with recurrent herpes simplex type 1 infection of the eye, lids, or mouth. The viral DNA of successive isolates from each patients was analyzed by restriction endonuclease fingerprinting. Evaluation of the DNA banding patterns of all isolates by means of two different enzymes, performed in a masked fashion, demonstrated that all of the isolates from any one patient had the same genetic makeup. These results indicate that recurrent herpes infections of the eye and face in humans are caused not by unrelated, serial infections but rather by reactivation of the same latent virus that remains in the ganglion over a period of years.

Rabbit corneal proteoglycans were labeled by intrastromal injection of 3H-glucosamine and 35S-sulfate 1 and 2 weeks after partial-thickness radial scalpel incisions. Proteoglycans were extracted with guanidine-HCl and purified by ion exchange chromatography. Wounding caused a marked decrease in the total incorporation of labeled precursors into proteoglycans. The labeled proteoglycans were more readily extracted with guanidine-HCl after wounding. Labeled proteoglycans from wounded corneas had a larger molecular size on gel filtration chromatography than did proteoglycans from control corneas, a result of an increased amount of keratan sulfate in the large molecular size fractions. Analysis of labeled glycosaminoglycan (GAG) from guanidine-extracted proteoglycans and from the corneal tissue after guanidine-HCl extraction showed an increase in the relative amount of heparan sulfate and keratan sulfate after wounding, and a decrease in relative amount of dermatan sulfate. The 35S:3H ratio of heparan and dermatan sulfates increased after wounding, and that of keratan sulfate decreased, suggesting changes in sulfation. Degradation of labeled dermatan sulfate with hyaluronidase and with periodate revealed a 2-fold increase in iduronic acid content and 2-4-fold increase in hyaluronidase-resistant dermatan sulfate in the wounded corneas. Reduction in proteoglycan content, reduced sulfation of keratan sulfate, and accumulation of a high-sulfate, high-iduronic acid dermatan sulfate are previously reported properties of proteoglycan in scar tissue from perforating corneal wounds. Demonstration of these properties in proteoglycan after wounds similar to radial keratotomy incisions suggests that deposition of scar tissue can result from wounds which do not damage Descemet's membrane.

We have investigated normal human corneas for the presence of T6-marker on Langerhans cells. With the exception of one pair of newborn corneas and two pairs of very young infant corneas, all HLA-DR-positive cells in central and peripheral corneal epithelium were T6-negative by double-labeled immunofluorescence. In contrast, epidermal sheets from normal human eyelid skin displayed positive staining for T6 on most of the HLA-DR-positive Langerhans cells. Since T6 antigen is considered to be a specific Langerhans cell differentiation marker, we interpret this finding to indicate a nonactivated or undifferentiated state of Langerhans cells in normal human corneas.

An unselected sample of 142 pregnant women had a single cervical culture for C trachomatis at 36 to 40 weeks' gestation. Of these women, 18 (12.7%) had positive cultures, and their infants were followed in postoperative fashion. Of these 18 infants, eight (44%) developed ophthalmia neonatorum. A combination of cultures and conjunctival smears for Giemsa staining and fluorescent-antibody examination for infected cells confirmed the diagnosis in 70% of the infants with conjunctivitis. However, 12 of 18 infants has serum antibodies against genital strain chlamydial antigens at 1 year of age, indicating that a majority of the infants were infected. Four of the infants had superior micropannus at 1 year of age; however, none of the infants had active conjunctivitis nor corneal or conjunctival scars.

We compared the efficacy of erythromycin ophthalmic ointment vs 1% silver nitrate drops for the prevention of neonatal conjunctivitis or respiratory tract infection from Chlamydia trachomatis. The organism was isolated from the cervix of 67 (12%) of 572 pregnant women. They gave birth to 559 infants who were randomly assigned to either prophylaxis immediately after birth. Thirty-six of 60 infants born to Chlamydia-positive women received silver nitrate; 24 received erythromycin. Twelve (33%) of the 36 infants who received silver nitrate had chlamydial conjunctivitis, but none of the 24 infants who received erythromycin did. Ten (29%) of 36 infants receiving silver nitrate had chlamydial nasopharyngeal infection (three later had pneumonia), as opposed to five (21%) of 24 who received erythromycin (one had pneumonia). Thus, erythromycin ointment is effective in prevention of chlamydial conjunctivitis, but it may not reduce nasopharyngeal infection or subsequent pneumonia.

The addition of a small metal housing containing a rechargeable flash to a Zeiss stereo slit lamp camera provides a simple, inexpensive method for obtaining excellent quality anterior segment fluorescein angiograms. By placing a splice in the slit illumination cord the fluorescein flash unit can be hooked up to be existing Zeiss power pack. The easy insertion of the proper excitation and barrier filters completes the temporary conversion. Utilizing this equipment, rapid sequence photographs of high resolution can be achieved. In addition, stereophotography, variable magnification, color photography and a simultaneous combination of fluorescein and infrared angiography for pigmented lesions are possible.

Rabbit corneas were exposed to heterologous guinea pig anti-rabbit antibodies in the presence of complement and cytotoxic damage to the endothelium was demonstrated using para nitroblue tetrazolium. The possible role of such antibodies as "blocking antibodies" and as cytotoxic antibodies in the corneal graft rejection process are discussed.

A 74-year-old woman had a radical anterior segment resection for epithelial ingrowth following cataract extraction. Light microscopy demonstrated the presence of a sheet of cells morphologically similar to conjunctival epithelium covering the superior half of the inner surface of the cornea, iris, and ciliary processes. Electron microscopy revealed that frequent hemidesmosomes and a well-developed basal lamina were consistently present along the base of the ingrowing epithelium. The tissue immediately beneath the ingrowing epithelium, lining the cornea, trabecular meshwork and iris, morphologically resembled the subepithelial zone that has been described along the human skin epidermal-dermal junction. Additionally, focal areas of necrosis were noted in the trabecular meshwork. The major structural alterations induced on the surfaces of intraocular structures by the invading epithelium and the associated necrosis probably are responsible for the glaucoma which occurs with epithelial ingrowth.

Three patients, including two brothers, with chronic mucocutaneous moniliasis and endocrinopathy were evaluated from an immunological viewpoint. Each patient had defective delayed hypersensitivity to Candida albicans as manifested by a negative skin test and absent lymphocyte response after in vitro exposure to the antigen. Cutaneous responses to other antigens were intact, and there were no demonstrable abnormalities in humoral immunity. In one case, the in vitro lymphocyte response was restored following an injection of a leucocyte extract from a skin test positive subject, although the cutaneous lesions remained unchanged.