Visual function correlates with nerve fiber layer thickness in eyes affected by ocular hypertension.

PURPOSE: To test whether the high variability observed when measuring pattern electroretinogram (PERG), visual evoked potentials (VEP), and spatial contrast sensitivity (SCS) in eyes with ocular hypertension is associated with variation in nerve fiber layer thickness, as measured by optical coherence tomography (OCT). METHODS: The study involved 32 untreated eyes (32 patients; age range, 29-64 years) showing a normal whiteon-white 24/2 Humphrey (San Leandro, CA) perimetry, IOP between 23 and 28 mm Hg, best corrected acuity of 20/20 or better, and none of the following papillary signs on conventional color stereo slides: rim notch(es), peripapillary splinter hemorrhages, or increased vertical-to-horizontal cup-to-disc ratio. On recruitment, each eye underwent SCS testing, OCT, PERG, and VEP recordings. Linear regression (Pearson's test) or Spearman's rank regression was adopted for the analysis of the data. RESULTS: The 95% confidence limits of the electrophysiological data were: PERG P50 latency, 59.3 to 63 msec; PERG P50 to N95 amplitude, 0.74 to 1.15 cmV; VEP P100 latency, 113 to 118 msec; VEP N75 to P100 amplitude, 3.81 to 4.90 micromV. The 360 degrees nerve fiber layer thickness overall (NFLO) ranged between 113 and 169 microm (145+/-16 microm; mean+/-SD) and significantly correlated with PERG P50 to N95 amplitude (r: 0.518; P = 0.002), PERG P50 latency (r: -0.470; P = 0.007), VEP N75 to P100 amplitude (r: 0.460; P = 0.008), VEP P100 latency (r = -0.422; P = 0.016) and SCS at 3 cyc/deg (r: -0.358; P = 0.044). CONCLUSIONS: The variability of PERG, VEP, and SCS testing observed in eyes with ocular hypertension is associated with differences in NFL thickness (the thinner the layer, the worse the visual function).     

Cytidine-5'-diphosphocholine (citicoline) improves retinal and cortical responses in patients with glaucoma.

PURPOSE: To evaluate the effects of cytidine-5'-diphosphocholine (citicoline) on retinal function and on cortical responses in patients with glaucoma. DESIGN: Randomized clinical trial. PARTICIPANTS: Forty patients with open-angle glaucoma were randomly divided into two age-matched groups: citicoline group ([GC] n = 25) and placebo group ([GP] n = 15). METHODS: The GC patients were treated with Neuroton (citicoline, 1000 mg/day intramuscularly) for 60 days; GP patients were treated with placebo (physiologic solution with additives) for 60 days. After 120 days of washout (day 180), the GC patients were divided into two age-matched groups: in 10 patients (GC1 group) the washout was prolonged for a further 120 days; in 15 patients (GC2 group) a second 60-day period of citicoline treatment was followed by a second 120-day period of washout. At day 180, the washout was extended for another 180 days in GP patients. In all subjects, retinal and cortical responses were evaluated by simultaneous recordings of visual evoked potentials (VEPs) and pattern-electroretinograms (PERGs) at baseline, after 60 days, and after 180 days. At day 300, VEPs and PERGs were also evaluated in GC1 patients, and at 240 and 360 days in GC2 and GP patients. MAIN OUTCOME MEASURES: Visual evoked potential parameters (P100 latency and N75-P100 amplitude); PERG parameters (P50 latency and P50-N95 amplitude); and intraocular pressure. RESULTS: The GP patients displayed similar VEP and PERG parameters in all examinations performed. In GC patients, the treatment with citicoline induced a significant (P < 0.01) improvement of VEP and PERG parameters, and their values were significantly different (P < 0.01) with respect to those of GP patients (P < 0.01). Visual evoked potentials and PERGs, recorded in GC patients after washout, revealed that although there was a worsening trend, the electrophysiologic improvement was still maintained. After a second period of washout, GC1 patients had VEP and PERG parameters similar (P > 0.05) to baseline ones and to those of GP patients. In GC2 patients, a second period of citicoline treatment induced a further (P < 0.01) improvement of VEP and PERG parameters CONCLUSION: Citicoline may induce an improvement of the retinal and of the visual pathway function in patients with glaucoma.     

Impaired saccadic eye movement in diabetic patients: the relationship with visual pathways function

The aim of this study was to evaluate whether a correlation existed between saccadic eye movements and visual pathways function in diabetic patients. Saccadic or fast Eye Movement System (EMS) and Visual Evoked Potentials (VEPs) were assessed in 20 insulin-dependent diabetic mellitus (IDDM) patients without long-term complications and in stable metabolic control and in 21 age-matched control subjects. In IDDM patients we observed significantly (p<0.01) longer EMS latency, while EMS velocity and accuracy were similar to those of controls; VEPs showed a significant delay in N75, P100, N145 latencies and significant reduction of N75-P100 and P100-N145 amplitudes. In IDDM patients no relationships between EMS and VEP parameters were found. In conclusion, EMS latency delay suggests an impairment of the saccadic eye movement system, while impaired VEPs may be ascribed to a dysfunction of the visual pathways. The lack of correlation between VEPs impairment and EMS latency delay suggests that in our IDDM patients the delay of saccadic latency cannot be exclusively related to a visual pathways dysfuction and could be ascribed to a diffuse neuronal involvement. This revised version was published online in July 2006 with corrections to the Cover Date.     

Chick gonadogenesis following early surgical bursectomy

Left ovaries of bursectomized chick embryos were examined on the 17th day of incubation in comparison to normal and sham-operated controls, by histological and histochemical observations. The results show that in bursectomized embryos the cortex appears irregulary developed, with a significant decrease in the mean thickness and in the percentage of the secondary sex cords in the total cortical area. Furthermore, the germinal epithelium appears thicker and the subcortical medulla and the tunica albuginea more compact. The greater activity of the enzyme ⁵–3-hydroxysteroid dehydrogenase ( ⁵3HSD) found in ovaries of bursectomized embryos (histochemical method) could be related to an endocrine dismetabolism affecting the cortical development. On the basis of these results and those of other authors, some hypotheses are advanced. In particular, an action of the bursal factor on GTH receptors could be the factor responsible of the enhanced steroidogenic activity altering the hormonal environment.     

Prenatal symmetrical thalamic degeneration with flexion spasticity at birth

The unusual occurrence of spasticity at birth with symmetrical thalamic damage was found in a male infant delivered at 36 weeks' gestation following an episode of traumatically induced premature labor at 32 weeks. The infant was found to be spastic in flexion with increased stretch reflexes, depressed primitive reflexes, and moderate flexion contractures. Computerized tomographic scans showed bilateral nonenhancing thalamic densities. Neuropathologically, the lateral thalamic nuclei and the red nucleus showed neuron loss, astrocytosis, and, as confirmed by electron microprobe analysis, calcified neurons. The striatum was uninvolved. These findings closely resemble those reported as "symmetrical thalamic degeneration in infancy" and are strongly reminiscent of the pattern of thalamic involvement frequently seen in status marmoratus. It would appear that there is a period during perinatal life in which the lateral thalamus can be rendered vulnerable to hypoxic-ischemic injury, and that the thirty-second week of gestation must be included within this period.     

HIV-related encephalitis presenting as convulsant disease

Because of the growing incidence of neurological disorders in HIV-infected patients, an early detection of the disease seems to be of paramount importance, especially in asymptomatic subjects. By using electroencephalography coupled with computerized spectral analysis and "mapping" (EEG-CSA), paroxysmal sharp activity was detected in 26 patients belonging to different stages of HIV infection. Seven of them (27%) were also symptomatic, (table; see text) showing signs of convulsant disease. The presence of focal or generalized paroxysmal activity, often associated with seizures, might suggest an early localization of HIV in cortical structures.     

Involvement of the ventrolateral medulla in parkinsonism with autonomic failure

OBJECTIVE: To determine whether patients with PD and autonomic failure (AF), manifested primarily with orthostatic hypotension (OH), have a consistent loss of tyrosine hydroxylase (TH) neurons in the rostral ventrolateral medulla (RVLM), similar to that occurring in patients with multiple system atrophy (MSA) and AF, and to determine whether there is loss of nicotinamide, adenine dinucleotide phosphate (NADPH) diaphorase (NADPH-d) RVLM neurons in both groups of patients. METHODS: The numbers of TH and NADPH-d neurons in the RVLM was assessed in brain sections obtained at autopsy from five patients with suspected PD and OH, six patients with MSA, two patients with corticobasal ganglionic degeneration and no AF, and 10 control subjects with no history of neurologic disease. Cell numbers were compared among groups and correlated with their final neuropathologic diagnosis. RESULTS: The number of TH neurons in the RVLM of patients with PD and OH were not significantly different from control subjects, and there were marked individual variations. The TH cell numbers in the RVLM were significantly higher (p < 0.06) in patients with PD than in patients with MSA, despite a similar degree of severity of OH. As a group, patients with PD and OH had reduced numbers of NADPH-d cells in the RVLM compared with control subjects, but again there were marked individual variations. NADPH-d cell numbers were reduced consistently and more markedly in patients with MSA. CONCLUSION: Unlike the case in patients with MSA, the number of TH neurons in the RVLM is highly variable in patients with PD and is unlikely to contribute significantly to the pathophysiology of OH. As a group, patients with PD have reduced numbers of NADPH-d neurons in the RVLM, but some patients had cell counts similar to control subjects. On the other hand, NADPH-d cell depletion in the RVLM is a consistent finding in MSA and may contribute to cardiorespiratory dysfunction in this disorder.