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Biomedical subjects

R F Gariano

Publications and source records attributed to R F Gariano.

At least 19 recordsLinked to original sources
PubMed2001

Progressive outer retinal necrosis and acute retinal necrosis in fellow eyes of a patient with acquired immunodeficiency syndrome.

PURPOSE: To describe an unusual concurrence of acute retinal necrosis and progressive outer retinal necrosis in fellow eyes of a patient with acquired immunodeficiency syndrome (AIDS). METHODS: Interventional case report. In a 37-year-old man with AIDS and herpes zoster keratitis in the right eye, progressive outer retinal necrosis developed in the right eye and acute retinal necrosis developed in the left eye. RESULTS: Disparate presentations of retinitis persisted in each eye, and retinal detachment and vision loss ensued in both eyes despite antiviral therapy. CONCLUSION: Distinct features of acute retinal necrosis and progressive outer retinal necrosis do not necessarily reflect systemic factors, and they may be variant manifestations of the same underlying infection.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Incidence and rate of disappearance of retinal hemorrhage in newborns.

OBJECTIVE: To determine the prevalance, associated biometric factors, and rate of disappearance of neonatal retinal hemorrhage. DESIGN: Cross-sectional and natural history study. METHODS: Healthy newborns (n = 149) at an urban hospital were examined using indirect ophthalmoscopy within 30 hours of birth. Newborns with retinal hemorrhage were reexamined biweekly until hemorrhage resolved. MAIN OUTCOME MEASURES: Neonatal and maternal biometric factors, and incidence and rate of resolution of retinal hemorrhage. RESULTS: Intraretinal hemorrhage was present in 34% of newborns and varied from a single dot hemorrhage in one eye to bilateral widespread hemorrhages, occasionally with white centers. The incidence of hemorrhage was higher for vacuum-assisted (75%) than for spontaneous vaginal deliveries (33%) and was least for infants delivered by cesarean section (7%). The mean maternal age was greater for infants with retinal hemorrhage. By 2 weeks after birth, retinal hemorrhage resolved in 86% of eyes, and at 4 weeks no intraretinal hemorrhage was detected, although a single subretinal hemorrhage persisted until 6 weeks after birth. CONCLUSIONS: Intraretinal hemorrhages are common in the immediate postnatal period and resolve by 1 month of age. Retinal hemorrhage in infants older than 1 month should heighten suspicion that the hemorrhage is associated with factors other than birth.

Connecticut↗
PubMed2000

Elevation of vitreous leptin in diabetic retinopathy and retinal detachment.

PURPOSE: Leptin is a cytokine that regulates energy metabolism and is linked to diabetes mellitus through its metabolic actions. Leptin is angiogenic and promotes wound healing, and therefore this investigation was conducted to determine whether leptin is associated with neovascular and fibrotic complications of diabetes and other retinopathies. METHODS: Serum and vitreous samples were collected from patients classified by the presence and type of diabetic retinopathy or other ocular diseases. Leptin was measured in serum and vitreous by radioimmunoassay, and leptin and leptin receptor were localized in epiretinal membranes immunohistochemically. RESULTS: Leptin levels in serum and vitreous were higher in patients with diabetes than in those without, and vitreous leptin concentrations were especially elevated in patients with proliferative diabetic retinopathy or retinal detachment. Leptin and leptin receptor were detected in fibrovascular epiretinal membrane of patients with diabetes. CONCLUSIONS: Leptin in human vitreous is elevated in proliferative diabetic retinopathy, and retinal detachment and is present in fibrovascular epiretinal tissue. These data suggest an involvement of leptin in retinal disease.

Adolescent↗
PubMed1998

Varicella zoster virus retrobulbar optic neuritis preceding retinitis in patients with acquired immune deficiency syndrome.

OBJECTIVE: This study aimed to describe a recently recognized and rare presentation of varicella zoster virus (VZV) retrobulbar optic neuritis preceding retinitis in patients with acquired immune deficiency syndrome and to identify factors that may relate to improved visual outcome. METHODS: Diagnosis, treatment, and clinical course are described for three eyes of two patients with this viral infection. RESULTS: Patients had decreased vision, headache, and recent zoster dermatitis. Varicella zoster virus retrobulbar optic neuritis was diagnosed on the bases of clinical, laboratory, and electrophysiologic examination results. Profound vision loss and peripheral retinitis ensued despite intravenous antiviral treatment. Combination intravenous and intravitreous antiviral injections were administered with dramatic visual recovery. CONCLUSIONS: Varicella zoster virus retrobulbar optic neuritis should be considered in immunocompromised patients with visual loss. Early diagnosis and aggressive combination therapy via systemic and intravitreous routes may enable return of useful vision.

AIDS-Related Opportunistic Infections↗
PubMed1996

Immunohistochemical characterization of developing and mature primate retinal blood vessels.

PURPOSE: To characterize developing retinal blood vessels with vascular markers and to relate the histochemical profile of maturing vessels to morphologic stages in retinal vascular development. METHODS: Vessels were examined in frozen and paraffin-embedded retinas and in wholemounts of Macaca monkeys ranging in age from fetal day 75 (F75) to adulthood. Endothelial cells were visualized immunohistochemically using antisera to von Willebrand's factor and CD31 with lectins Ulex europaeus, Bandeiraea simplicifolia, peanut agglutinin, Ricinis communis, and wheat germ agglutinin, and by ATPase and ADPase enzymatic histochemistry. Antibodies to vascular basement membrane and matrix markers laminin, fibronectin, and collagen types I and VIII, and antisera recognizing cell cycle-specific nuclear proteins (cyclin, Ki-67, Mib-1) also were used. RESULTS: Newly formed and mature vessels were reactive with reagents specific for CD31, von Willebrand's factor, types I and VIII collagens, laminin, fibronectin, U. europaeus, R. communis, and peanut agglutinin. Wheat germ agglutinin labeled vessels only after pretreatment with neuraminidase. All vascular markers appeared simultaneously, but some were distributed differentially between capillaries and larger vessels, along the central-peripheral extent of a vascular plexus, and among different vascular laminae. Markers of vessels failed to label spindle-shaped presumed vascular precursor cells lying peripheral to the advancing vessels during development. Spindle cells exhibited cyclin, Ki-67, and Mib-1 immunoreactivity. CONCLUSIONS: Immature and mature vitread and sclerad vessels displayed histochemical profiles that were qualitatively similar but that had subtle quantitative differences. Results do not support identification of spindle-shaped cells as vascular precursors in the developing monkey retina and are discussed in relation to mechanisms of retinal vascularization.

Aging↗
PubMed1996

Development of astrocytes and their relation to blood vessels in fetal monkey retina.

PURPOSE: To determine the development of astrocytes and their vascular relations in Macaca monkey retina. METHODS: Sections and wholemounts of retinas from fetal day (Fd) 65 to adult animals were analyzed immunohistochemically to detect glial fibrillary acidic protein (GFAP) and vimentin. RESULTS: Astrocytes appeared first near the optic disc, then subsequently further peripherally, but avoided the fovea. In the nerve fiber layer, round and ovoid cells extended processes parallel to ganglion cell axons. In the ganglion cell layer, ovoid and stellate cells exhibited anisotropic processes or a honeycomb network. The inner lamina of astrocytes developed ahead of the outer lamina, and both reached their final positions before birth. Astrocytes lay more peripherally than did developing blood vessels, and the growing edge of nerve fiber layer vessels lay between the two astrocytic layers. Spindle cells, which may be vascular precursor cells, often aligned along linear astrocytic processes. Occasional spindle-shaped cells containing GFAP or vimentin were identified as immature glia. Astrocytes and blood vessels coincided regionally during development, but astrocyte processes were typically not in register with the meshwork of growing blood vessels. Astrocyte-vessel associations increased during fetal life and postnatally. CONCLUSIONS: During development, astrocytes display the same bilaminar pattern and morphologies present in adult retina. Astrocytes and blood vessels exhibit a similar regional distribution, but develop in distinct spatial patterns. Vessel investment by astrocytic processes increases during fetal life but is variable at all ages.

Animals↗
PubMed1994

Retinal toxicity of the antimetabolite 5-fluorouridine 5'-monophosphate administered intravitreally using multivesicular liposomes.

BACKGROUND: Liposome-encapsulated 5-fluorouridine-5'-monophosphate (FUMP) has been shown to inhibit proliferative vitreoretinopathy in a rabbit model. Liposome encapsulation extends the intravitreal half-life of this antiproliferative drug by a factor of 28 times. METHODS: The current study investigated the retinal toxicity of intravitreal injections of 10, 50, and 100 micrograms FUMP as free drug or within liposomes in rabbits. Evaluation included ophthalmoscopic examination, electroretinography, and histologic analysis by light and electron microscopy. RESULTS: No electroretinographic evidence for toxicity of FUMP was found. Light and electron microscopy showed only mild transient vacuolization in the outer segment layer, without inflammation. Empty liposomes incurred no toxic effects on the retina. CONCLUSIONS: Our results suggest that liposome-encapsulated FUMP may be non-toxic to the retina at doses that inhibit proliferative retinopathy.

Animals↗
PubMed1994

Vascular development in primate retina: comparison of laminar plexus formation in monkey and human.

PURPOSE: The temporal and spatial sequence of development of laminar vascular plexuses was determined qualitatively and quantitatively in monkey and human retina. METHODS: Histologic and cytochemical methods were used to study Macaca monkey eyes from fetal day 55 (F55d; birth = F168d) to 17 years, and human retina from fetal 21 weeks to adult. RESULTS: In monkey retina, spindle-shaped, presumed vascular precursor, cells appear at F55d in the nerve fiber layer (NFL) adjacent to the optic nerve. The vascular plexuses in the NFL-ganglion cell layer appear first and form in the presence of spindle cells. Nerve fiber layer vessels extended radially to reach the temporal ora at F95d and nasal ora at F110d. The capillary plexus at the inner border of the inner nuclear layer (INL) appears at F120d near the optic disc, whereas the plexus at the outer INL border appears at F130d. Both reach their final position before birth. The INL plexuses form by endothelial budding from more vitread vessels in the absence of spindle cells. In the NFL, vessel growth to match retinal growth at the ora also involves endothelial budding. The growth rate of all plexuses was approximately 225 microns/day. The central fovea and the most peripheral retina adjacent to the ora serrata remained avascular throughout development. Differences between humans and monkeys include: Human vessels complete maturation after birth; human vessels reach the nasal ora earlier than the temporal ora; and spindle cells are more abundant and dispersed over a greater area within human NFL. Growth rates of human plexuses were comparable to those in monkeys. CONCLUSION: In both primates, deeper capillary plexuses form only by extension from existing vessels (angiogenesis). In the NFL, early vessel formation involves spindle precursor cells (vasculogenesis). The main difference between monkey and human in these processes is that the mature monkey vascular pattern is established well before birth.

Adolescent↗
PubMed1993

Ocular examination and diagnosis in patients with the acquired immunodeficiency syndrome.

Ocular involvement is seen frequently and is an important source of morbidity in patients with the acquired immunodeficiency syndrome. We outline here the general skills of physical diagnosis valuable to primary care physicians or infectious diseases specialists in recognizing and evaluating ocular complaints in patients infected with the human immunodeficiency virus. We provide an overview of common ocular diseases in these patients, with an emphasis on signs and symptoms that aid in the differential diagnosis.

AIDS-Related Opportunistic Infections↗
PubMed1990

Effects of long-term administration of haloperidol on electrophysiologic properties of rat mesencephalic neurons.

Haloperidol (1.5-1.7 mg/kg/day) was administered to rats via their drinking water for periods of either 4 weeks or 13 to 14 months, after which the animals were withdrawn from the neuroleptic for 1 or 2 weeks, respectively. Rats given haloperidol for 13 to 14 months exhibited significantly more perioral dyskinesias than controls. Single-unit extracellular recordings were obtained from the substantia nigra and ventral tegmental area in subjects under urethane anesthesia. After 1 month and after 1 year of treatment, a significant decrease in the mean firing rate of substantia nigra pars reticulata neurons was found. Subtle changes in the response of pars reticulata neurons to striatal stimulation were seen after extended haloperidol intake. No consistent effects of haloperidol administration for 4 weeks or 13 to 14 months were found for either the number of spontaneously active dopamine neurons or their firing rates. Histopathologic assessment of tissue from dorsomedial, dorsolateral and ventrolateral sectors of the striatum revealed no significant effect of long-term haloperidol treatment on neuronal cell counts. The results are discussed with reference to neuroleptic-induced tardive dyskinesias.

Animals↗
PubMed1989

A mechanism for the involvement of colocalized neuropeptides in the actions of antipsychotic drugs.

Evidence has accumulated to implicate neuropeptides localized within midbrain dopamine neurons (cholecystokinin, neurotensin, acetylcholinesterase) in synaptic transmission, mental disease, and pharmacotherapy. We suggest a means by which antipsychotic drugs alter the dynamics between dopamine and colocalized peptides: the intrinsic ability of these agents to stimulate dopamine neuronal activity while blocking dopamine receptors modulates the ratio of catecholaminergic to peptidergic transmission within the mesotelencephalic system. Imbalances of peptide and dopamine cotransmission and their modulation by neuroleptics may be relevant to the pathogenesis and pharmacotherapy of schizophrenia.

Animals↗
PubMed1989

Mesocortical dopaminergic neurons. 1. Electrophysiological properties and evidence for soma-dendritic autoreceptors.

Mesencephalic dopaminergic neurons were electrophysiologically identified by a variety of criteria, including antidromic activation from prefrontal or cingulate cortex, neostriatum, or nucleus accumbens in urethane-anesthetized rats. The mean firing rate of 98 mesocortical dopaminergic neurons was 2.9 +/- 0.3 spikes/sec and did not differ from the mean firing rate found for nigrostriatal or nucleus accumbens dopaminergic neurons. Spontaneously active mesocortical dopaminergic neurons were inhibited by intravenous administration of either apomorphine (6 micrograms/kg) or amphetamine (0.25 mg/kg). Whereas most antidromic responses of nigrostriatal and mesoaccumbens neurons consisted of the initial segment spike only, cortically-elicited antidromic responses typically consisted of a full initial segment-soma-dendritic spike. These findings are discussed with regard to the presence of soma-dendritic autoreceptors on mesocortical dopaminergic neurons.

Action Potentials↗
PubMed1989

Mesocortical dopaminergic neurons. 2. Electrophysiological consequences of terminal autoreceptor activation.

Measurement of drug- and stimulation-induced changes in the electrical excitability of dopaminergic terminals was employed to assess the effects of stimulation of dopamine terminal autoreceptors in the prefrontal cortex in urethane-anesthetized rats. Systemic or local administration of amphetamine decreased, whereas systemic administration of haloperidol increased the excitability of prefrontal cortical dopaminergic terminals of ventral tegmental area dopaminergic neurons. Mesoprefrontal dopaminergic terminal excitability was also responsive to spontaneous and stimulation-induced alterations in the rate of impulses reaching the terminal fields. These results are comparable to those previously reported for nigrostriatal and mesoaccumbens dopaminergic neurons, and are discussed with regard to the operational characteristics of autoinhibition in the mesocortical dopaminergic system.

Action Potentials↗