Prognosis of cystoid macular edema after retinal detachment repair

Twenty eyes of 20 patients who had undergone successful retinal detachment repair by means of microsurgery had cystoid macular edema (CME) disclosed by fluorescein angiography 10-12 weeks postoperatively. Clinical evaluation war repeated at 6-month intervals for a period of 12-30 months. Sixteen eyes were followed for at least 18 months. CME spontaneously cleared or dramatically decreased in 12 of the 16 eyes (75%), which were followed for at least 18 months. CME had spontaneously cleared in 50% of the eyes by the end of 1 year after surgery. For those eyes with transient CME, the mean visual acuity improved from 0.3 at 3 months postoperatively to 0.6 at the end of the follow-up period. The final visual acuity was 0.4 or better in 83.3% of the eyes with transient CME. None of the eyes with persistent CME developed premacular fibrosis or cystoid macular degeneration during the follow-up period. No prognostic factor for angiographic CME after repair of retinal detachment could be determined in the present series of patients.

Influence of magnesium deficiency on liver collagen after carbon tetrachloride or ethanol administration to rats

The effects of magnesium deficiency on liver collagen after the administration of a hepatotoxic substance were investigated. Rats, fed a control or magnesium-deficient diet (0.040 g/kg), received six CCl4 or mineral oil injections administered at 2-d intervals starting from the first day of diet treatment. They were killed 3 or 12 d after the last injection. Between postinjection d 3 and 12, no change of magnesium concentration in liver was observed in the deficient rats. Three days after the end of treatment liver calcium in the magnesium-deficient CCl4-treated rats was higher than in any other group. Liver collagen of untreated control rats and untreated magnesium-deficient rats was not significantly different. In control and magnesium-deficient animals receiving CCl4 treatment, the liver collagen levels were significantly higher than in untreated rats. The magnesium-deficient rats receiving CCl4 have higher liver collagen than the controls receiving CCl4. In a second experiment the effect of suboptimum intake of magnesium (0.120 g/kg) combined with the ingestion of ethanol was studied in rats given a solution of ethanol in water for 55 d as their only source of fluid. Mortality occurred in the magnesium-deficient rats receiving ethanol, and body weights of these rats were lower than those of animals in the other three groups. The collagen concentration in liver was higher in magnesium-deficient rats consuming ethanol than in any other group. The synergistic action between magnesium deficiency and ethanol therefore appears to be analogous to that observed with CCl4.

An ultrasonographic study of choroidal indentation height after scleral buckling with lyophylized human tissues

The height of the choroidal indentation produced by 26 lamellar scleral pockets filled with lyophylized human fascia lata and by 9 exoplants made up of lyophylized human dura mater was measured with A-scan and B-scan ultrasonography. The mean height of the choroidal indentation produced by lamellar scleral pockets was 4.3 mm 5-20 days postoperatively, 3.2 mm 3 months postoperatively, and 2.5 mm 6-9 months postoperatively. The mean height of the choroidal indentation produced by exoplants made up of dura mater was 4.6 mm 5-20 days postoperatively, 3.5 mm 3 months postoperatively, and 2.9 mm 6 months postoperatively.

Preparatory process for anticipatory postural adjustments: modulation of leg muscles reflex pathways during preparation for arm movements in standing man

We have investigated, in 6 standing subjects, the time course of amplitude changes in the short latency (40-60 ms) and long latency (60-80 ms) reflex response components of gastrocnemius medialis (GM) and soleus (S) muscles during the preparatory period (time between a warning signal and a response signal) as a function of the precued direction (pull or push) of arm movement. Subjects maintained their standing posture by visual feedback during the 1.5 s preparatory period of a reaction time task. A warning signal gave advance information concerning the voluntary response to be performed which consisted of either a pull or push movement of the right arm. The excitability of the reflex pathways was evaluated by triggering a rapid rotation of the right ankle joint (dorsiflexion) applied randomly at 100, 300 or 500 ms before the response signal for arm movement. Statistical analysis of EMG amplitude (ANOVA) showed that preparatory effects were different for the two synergistic muscles with both short (spinal) and longer latency components of GM showing generalized facilitation and of S showing generalized inhibition. In addition, the longer latency, presumably supraspinal, component of the two muscles was differentially modulated according to directional advance information, showing relative facilitation for pull as compared to push trials. These reflex response modulations were emphasized in faster reaction time (RT) performers at the end of the preparatory period. It is concluded that postural preparatory processes are reflected at the spinal level in global effects and at the supraspinal level in directionally specific effects.

Histamine and serotonin suppression of lymphocyte response to phytohemagglutinin and allogeneic cells

Histamine added to murine spleen cells suppressed in vitro proliferation of lymphocytes induced by PHA or allogeneic spleen cells. Another vasoactive amine, serotonin (5-hydroxytryptamine), exerted a similar inhibitory activity on PHA- or allogeneic cell-induced lymphocyte proliferation. Anti-H2 histamine antagonists, cimetidine, metiamide, and ranitidine, blocked the histamine and serotonin suppressive effect. Cyproheptadine, an anti-H1 histamine and anti-serotonin antagonist, and methysergide, an anti-serotonin antagonist, also blocked histamine and serotonin inhibitory activities. These data suggest the presence, on lymphocytes, of receptors for serotonin which might be related to histamine receptors.

Clinical factors predisposing to massive proliferative vitreoretinopathy in rhegmatogenous retinal detachment

A series of 354 consecutive rhegmatogenous retinal detachments, operated on by means of microsurgery, is evaluated to determine the clinical factors that may predispose to the development of postoperative massive proliferative vitreoretinopathy (MPVR). Three statistically significant parameters in the development of postoperative MPVR are demonstrated: failure of previous surgery, preoperative fixed retinal folds, and horseshoe retinal tear(s) exposing a total surface of 3 disc diameters or more of pigment epithelium. For further study, it is suggested that in retinal detachments with such horseshoe tears, early destruction of the exposed pigment epithelium by argon laser photocoagulation may be a valuable means of decreasing the incidence of MPVR after retinal detachment repair.

[Treatment of retinal capillary angiomas of von Hippel's disease]

Twelve patients with Von Hippel's disease were observed by the authors during the last decade. 4 patients developed new retinal or papillary angiomas during the follow-up period (1 to 10 years with an average of 4,5 years). 55 retinal capillary angiomas and 2 papillary angiomas were observed in the present series. All retinal angiomas were submitted to treatment. Cryotreatment under biomicroscopic control of the fundus was applied on 11 angiomas, argon laser photocoagulation was applied on 36 angiomas, and 8 angiomas were treated with both techniques. Clinical destruction of the angiomas and normalization of the feeder vessels caliber were achieved in all cases. At the end of the follow-up period the visual acuity was the same or better in 16 of the 17 treated eyes; the visual acuity was worse in 1 eye. The smaller the retinal angioma the easier, the more efficient and the less mutilating the treatment is. Therefore the patients should be followed up at regular intervals in order to treat incipient lesions rather than large tumors.

Anticipatory changes of long-latency stretch responses during preparation for directional hand movements

We have investigated, in 9 normal subjects, the time course of amplitude changes in the automatic long latency stretch reflex of wrist flexors during the preparatory period as a function of the precued direction of hand movement. Subjects maintained right hand position against a weak force and learned to compensate precisely for brief ramp stretch (250 deg./s, 50 ms) which imposed wrist extension. This probe stretch was applied randomly at different times during the 1 s preparatory period of a reaction time task. The warning signal gave directional advance information (DAI) about the voluntary movement that had to be performed. The EMG activity, recorded between 20 and 80 ms after the stretch started, was measured in terms of 3 successive components, M1, M2 and M3, identified on the basis of their respective latency. There was no significant change in the M1 component. Following a warning signal which precued an extension movement, M2 was depressed prior to the response signal. The time course of M3 was clearly different according to DAI: it increased following a warning signal which precued a flexion movement and decreased in the alternative case. This difference reached statistical significance 400 ms before the response signal. In fast-performing subjects the differential development of M3 was more marked than for slow-performing subjects. This underlines its preparatory significance. These results suggest that the neuronal pathways involved in the M3 response to stretch: i, are partly different from those conveying the earlier components, and ii, include structures which take part in the pre-programming of rapid movements.