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Biomedical subjects

G Cristini

Publications and source records attributed to G Cristini.

At least 19 recordsLinked to original sources
PubMed1997

Diagnostic and prognostic indices in primary open angle glaucoma: a color Doppler study.

The authors compute a diagnostic (Di) and a prognostic (Pi) index in primary open angle glaucoma. Four groups of patients were studied. Group A consisted of subjects under 50 years of age, group B of subjects over 50 years of age, group C of patients with normal tension glaucoma and group D with high tension glaucoma. All patients underwent color doppler imaging of the ophthalmic, posterior ciliary and choroid arteries. The Di of the choroid vessels were 0.967 +/- 0.011 (gp. A), 1.112 +/- 0.010 (gp. B), 1.506 +/- 0.008 (gp. C) and 2.891 +/- 0.083 (gp. D). The Pi of the posterior ciliary arteries were 22.700 +/- 1.160 (gp. A), 20.000 +/- 0.943 (gp. B), 15.100 +/- 0.568 (gp. C) and 12.100 +/- 0.083 (gp. D). Confirmation of these data might validate them as a tool for preventing the evolution of glaucomatous optic neuropathy.

Adult↗
PubMed1992

Zidovudine prophylaxis after accidental exposure to HIV: the Italian experience. The Italian Study Group on Occupational Risk of HIV Infection.

OBJECTIVES: To evaluate the use of zidovudine prophylaxis in HIV-exposed health-care workers (HCW) in Italy and to determine its short-term toxicity. DESIGN: Longitudinal, open study with retrospective and prospective collection of data. SETTING: All Italian clinical centres that care for HIV-infected patients and are licensed by the Ministry of Health to dispense zidovudine and 30 hospitals participating in the Italian Multicentre Study on Occupational Risk of HIV Infection. STUDY POPULATION: HCW and other individuals who accepted zidovudine prophylaxis after accidental exposure to HIV. RESULTS: Data were collected for 224 HIV-exposed individuals until 30 June 1991. An increase in zidovudine prophylaxis was observed. All but 10 subjects received 1000-1250 mg zidovudine per day. Anaemia (five cases), neutropenia (one case) and an increase in serum alanine aminotransferase levels (two cases) were the only haematochemical side-effects observed; none of the subjects ceased prophylaxis because of side-effects. More than 50% of subjects had constitutional reactions; as a result, prophylaxis was stopped by 29 patients. These adverse effects began within 10 days of prophylaxis; all resolved after prophylaxis was stopped. No HIV-antibody seroconversions were observed after a mean follow-up of 8 months. CONCLUSIONS: Zidovudine prophylaxis has become a feature of the management of occupational exposures to HIV in health-care settings; short-term toxicity is mild, dose-related and reversible. Further studies are needed to assess the risk of long-term sequelae.

Administration, Oral↗
PubMed1991

Choroidal thickness in primary glaucoma.

A and B scan echography does not allow to measure separately the thickness of the three ocular layers, retina, choroid and sclera. This, however, is possible by radiofrequency signals. 48 eyes of normal subjects and 21 eyes of patient suffering from chronic glaucoma with ocular hypertension from 30 to 45 mm Hg were examined. The thickness of the retina and sclera was equal in the two groups, whereas the thickness of the choroid in the glaucomatous eyes showed an increase of 20% as compared with normal eyes.

Adult↗
PubMed1990

A case of cryptococcal meningoencephalitis and focal cerebral vasculitis with transient immunodeficiency.

The AA. report a case of CNS cryptococcosis with vasculopathic complications in a woman in perfect physical conditions. The patient was admitted to hospital after complaining for 20 days of fever, headache and rachialgia. CSF examination revealed hypoglicorrachia (18 mg %), cells 440 mmc (polymorphonuclear leukocytes 90%), brain CT scan negative. During antimycobacterial treatment right hemiparesis appeared; brain CT: hypodense lesion in the posterior brachium of the left inner capsule; at its base the lesion showed a hypodense streak coherent with thromboembolic damage or deep vasculitis. OKT4 lymphocytes were 6% (absolute number: 70). The antimycotic treatment, following the positive reaction of the CSF culture to Cryptococcus Neoformans, entirely cured the hemiparesis and normalized the CSF while OKT4 lymphocytes rapidly grew.

Brain Diseases↗
PubMed1990

HIV1-Ag in cerebrospinal fluid during AIDS.

HIV infection may display neurological symptoms at any stage; the virus can be isolated from the cerebrospinal fluid (CSF) of both symptomatic and asymptomatic patients and of two third of patients with AIDS. This study sought to determine the sensitivity of HIV1-Ag in the CSF of an HIV-Ab positive population to evaluate its diagnostic and/or prognostic significance. CSF HIV1-Ag was dosed in 48 patients: 9 patients belonged to the III CDC group, 2 to group IVA, 1 to IVB and 36 to IVC1. In the last group, 14 patients had not opportunistic infections of the CNS. The tests proved positive in: 1 IVB patient and 16 IVC patients with focal lesions of the CNS or cerebral atrophy; HIV1-Ag was present in the CSF of 63% of patients displaying neurologic symptoms and it reached 84% in patients with diffuse CNS pathology.

Acquired Immunodeficiency Syndrome↗
PubMed1982

Effect of kainic acid, glutamate, and aspartate on CO2 production by goldfish tectal slices.

For a study of the excitatory effect of kainate, glutamate, and aspartate in the goldfish optic tectum, these substances were tested on the production of CO2 from radioactive glucose in tectal slices incubated in Krebs-Ringer medium for fish. Kainate increased the rate of CO2 production for up to 30 min in a dose-related manner, the effect being maximum at 0.1 mM concentration and decreasing at higher doses. The effect was blocked by ouabain (1 mM) as well as by the substitution of choline for Na+ in the incubation medium. Glutamate and aspartate exerted a less pronounced excitatory effect on CO2 production at higher concentration than kainate. This effect was also abolished by ouabain. Glutamate, added to the medium at a concentration at least 100-fold higher than kainate, partially reversed the increase in CO2 production induced by kainic acid. No similar effect was noticed for aspartate. The supposed glutamate antagonists glutamic acid diethylester (1 mM) and proline (5 mM) did not affect the excitatory action of kainic acid or exert an antagonistic effect towards glutamate. At higher concentration (10 mM) glutamic acid diethylester increased CO2 production, an effect that was, however, ouabain insensitive. Methyltetrahydrofolic acid (1 mM), a substance reported to compete for the kainate receptor, did not inhibit the effect of kainic acid or increase CO2 production.

Animals↗
PubMed1981

Kainic acid neurotoxicity does not depend on intact retinal input in the goldfish optic tectum.

Kainic acid neurotoxicity has been studied in the optic tectum of the goldfish 4 weeks after eye enucleation. The effect of drug treatment has been tested with respect to both neurochemical and morphological parameters. The neurotransmitter-related enzymes, choline acetyltransferase, acetylcholinesterase and glutamate decarboxylase, show about 50% decrease in the deafferented tectum 6 days after kainic acid administration. Relevant morphological alterations of the tectal structure can also be noticed at the same stage. The neurotoxic effects of kainic acid in the deafferented optic tectum are therefore quite similar to the effects of previously noticed for the intact optic tectum of normal fish. Control experiments on the effect of optic nerve degeneration by itself on the levels of the neurotransmitter-related enzymes in the optic tectum, have shown no significant decrease in glutamate decarboxylase, a slight decrease in acetylcholinesterase and a more marked drop in choline acetyltransferase. The findings are discussed with reference to some of the hypotheses advanced in order to explain kainic acid neurotoxicity. It is proposed that the neurotoxic effect of kainic acid after removal of specific excitatory afferents, may vary in different nervous centers depending on differences of the remaining extrinsic connections and of the intrinsic neural circuits.

Acetylcholinesterase↗
PubMed1980

Evidence of intrinsic cholinergic circuits in the optic tectum of teleosts.

Choline acetyltransferase (CAT) was assayed in the optic tectum of 4 teleost species with different visual powers. The results showed a close relationship between the enzyme levels in the optic tectum and the development of the visual system. In the more visual species, the trout, CAT activity in the optic tectum was about 30-fold higher than in the catfish, whose visual system is much less developed. Two species with intermediate development of the visual system, the goldfish and the tench, showed intermediate levels of CAT activity. Kainic acid treatment caused a significant decrease in both CAT and acetylcholinesterase (AChE) in the goldfish optic tectum. Concomitant histological examination showed, among other effects, the disappearance of most neurons belonging to the pyramidal and fusiform type in the striatum fibrosum and griseum superficiale of the tectum. The comparative and experimental data therefore suggest that the relationship between cholinergic mechanisms and the visual function is, to a significant extent, connected with the presence of intrinsic cholinergic circuits in the optic tectum. The relevance of these findings, also in relation to the problem of the identification of the retino-tectal transmitter, is discussed.

Acetylcholinesterase↗
PubMed1980

Ocular hypertension in primary glaucoma: a new hypothesis.

Some considerations of the vascular events occurring the uvea during the course of glaucoma are reported and a mathematical model is adopted to clarify the interdependence between intraocular pressure, rate of blood flow, blood pressure gradient, and the number of unobstructed capillary vessels in the uveal membrane. By means of this mathematical model the physiopathological vascular cause of the rise in intraocular pressure is confirmed (also independently of an obstacle to aqueous outflow), and the clinical implications in relation to visual sensory impairment are emphasized.

Capillaries↗
PubMed1979

Pressure lowering effect of timolol with reference to its topical vascular action.

The hemodynamic effect of timolol maleate in open angle glaucoma was studied rheo-oculographically. Increase in the ocular pulse which reaches maximal amplification 2 h after the instillation of the drug was observed. The maximal pressure lowering effect appeared 3 h after instillation, as if the hemodynamic effect were the trigger for the pressure lowering effect.

Administration, Topical↗
PubMed1977

Multivariate analysis of visual evoked response.

The visual potentials evoked by flash are analyzed in healthy subjects in cases of retinal detachment, of optic nerve lesions, and of amblyopia by means of different statistical methods: 1. Analysis of the various features of the response, evaluated separately 2. Analysis of the interdependence between the measures of the various features The first method supplies information on the differences in 'size' of the curves in the various samples, the second method reveals differences of 'shape'. The second method has proved to be able to distinguish both normal conditions from pathologic impairment of optic structures and the different sites of the lesions.

Adolescent↗
PubMed1975

A new method for determining the blood quantity in the eye in a unit of time.

The principles of rheography with "infinite time constant" are utilized. After applying a suction cup electrode mechanism, by gradual increases of the vacuum, ocular pressure rises above venous pressure, and without modification of arterial inflow, the venous outflow is blocked; in consequence an increase of blood accumulation in the interior of the eye occurs. The electrical impedance variation, as a result of the latter, gives the recorded tracing a "slow" rising curve, that maintains the same pulse morphology. After being analyzed and elaborated on with certain mathematical formulae, this curve makes it possible to calculate the blood flow in the eye in a unit of time. Statistics on normal patients of various ages are reported.

Eye↗