Effects of age of blinding on rhythmic pituitary-adrenal function in female rats

These experiments were designed to study the effects of age of blinding on the circadian rhythm in pituitary-adrenal function in female rats. In the 1st experiment, the eyes were removed at 1 day of age and serial blood samples were obtained at 6-h intervals for 24 h at 45 days. In the 2nd experiment, rats were blinded at 1,26 or 60 days of age, and serial blood samples were collected at 4-h intervals for 44 h when the rats were 84, 112 and 142 days of age. Intact and sham-operated rats served as controls. Plasma corticosterone (cpd B) concentrations, measured fluorometrically, were used to assess pituitary-adrenal function. Blinding disrupted cpd B patterns in all groups on all occasions. However, steroid patterns of individual rats suggested the presence of free-running 24-h rhythms. This suggestion was supported by the results of aligning the steroid peaks of individual blinded rats. This procedure yielded group patterns of steroid levels which were comparable to those of controls. The periodic stimuli available to the blinded rats from intact rats in the same and adjacent cages did not synchronize this rhythm. These results suggest that the eyes and their central projections are not essential after birth for the development and maintenance of rhythmic pituitary-adrenal function; these structures appear necessary, however, for synchronization with light-dark cycles.

Influence of pinealectomy on serum estrogen and progesterone levels in blind-anosmic female rats

Previous studies show that the suppression of gonadal function in blind-anosmic rats is dependent on the pineal gland. The present results demonstrate that in young female rats both the pineal gland and dual sensory deprivation have additional independent antigonadal effects.

The rate of phase shift of plasma corticosterone circadian rhythm during early developmental stages in neonatally blinded rats

The phase shift of circadian periodicity of pituitary-adrenocortical activity was studied in neonatally blinded infant rats. The phase shift of the rhythm was surprisingly rapid during the early stage of prepubertal period, while changes in the rhythm pattern were rather small after puberty, as indicated by a slight shift of the acrophase. Low amplitude was observed in the group data of blinded rats after puberty.

[Amaurosis fungax. Studies on hemodynamics and platelet function]

Thirty-eight patients with amaurosis fugax were examined ophthalmologically. In 12 of these cases carotid occlusion was diagnosed by ophthalmodynamography and Doppler ultrasonography of the orbital vessels. Angiographic substantiation was possible in nine of these patients. The pathognomonic importance of amaurosis fugax for occlusive carotid disease is clearly shown by these findings. The plasma concentration of platelet specific proteins was examined in 32 patients and found to be pathologically increased in 13 cases. Spontaneous aggregation of platelets and circulating platelet aggregates were only found in a few patients. Due to the lack of coincidence between the event of amaurosis fugax and the time when platelet function tests were made no definite conclusions may be drawn from these results. Yet disturbances of platelet function must be taken into consideration in the pathogenesis of amaurosis fugax.

Changes in serum prolactin following binding and constant light exposure

The effects of blinding and constant light exposure for 5 weeks on serum concentrations of prolactin were studied in male rats. Neither treatment had any effect on body, pineal, pituitary, testis, or seminal vesicle weights. Serum prolactin was not significantly altered by constant light exposure, but was significantly elevated by blinding. These data provide further support that prolactin secretion is elevated by blinding. It is suggested that prolactin may be partially responsible for the lack of significant gonadal atrophy following blinding in male rats.

Mutual influence of rats having different circadian rhythm of adrenocortical activity

The possibility of a mutual influence between male adult rats having different circadian adrenocortical rhythms was studied under two different lighting conditions. Intact and optic-enucleated rats were housed together in the same cage in various ratios of intact to blinded rats. Twenty-four- or forty-eight-hour patterns of plasma corticosterone levels were determined individually at 4-h intervals. Under diurnal light-dark alternation, the circadian periodicity of the intact rats always synchronized with light, whereas single blinded rats in cages with three intact rats demonstrated free-running rhythms throughout the experimental period of 15 wk. Under constant light the circadian rhythm free-ran in both intact and blinded rats for the first 2 wk. A phase reversal of the rhythm was observed in the intact rats at the end of the 2nd wk, and between 5 and 8 wk after binding in the blinded rats. These results indicate that the circadian adrenocortical rhythms in intact and blinded rats are not entrained to each other, even when the two types of rats live together in the same cage.

[Effect of the changes of epiphysial functions on the central and peripheral immune system in mice]

Endocrine function of thymus estimated by titer of thymic serum factor is inhibited in pubertal mice CBA/Ca under conditions of pharmacological inhibition of epiphysis function by beta-adrenoblocking agent anapriline. After blinding and epithalamine and melatonine introduction the content of thymic hormone considerably increases. Melatonine is characterized by manifestation of effect in earlier periods of research. In mice with hyperfunction of epiphysis mass, cell character of thymus and spleen increase as well as the content of thymosine-like activity in supernatant of cultures of splenocytes. And on the contrary, in animals with hypofunction of epiphysis the values of studied immunological indices decrease. Immunopotentiating effect of epiphysial factors is observed not only in vivo but also in vitro and decreases in thymectomized mice. The change of the concentration of glucocorticoids in the organism is of significance in the mechanism of epiphysis effect on the immune system.

Complement-induced vascular leukostasis. Its role in tissue injury

The plasma complement system evolved as a beneficial antimicrobial mechanism. However, this system can be activated chaotically in such situations as extracorporeal perfusion, trauma, sepsis, or acute pancreatitis. When so activated, the complement component C5a may aggregate granulocytes and cause leukoembolization; it is suggested that such leukoembolization is an important, previously unsuspected mechanism of tissue damage. In addition, toxic oxygen species, such as superoxide, that are produced by granulocytes that have been triggered by C5a can damage the endothelium, an event that may, if it occurs in the lungs, contribute to the development of the adult respiratory distress syndrome (ARDS). Hence the previously empiric use of high doses of corticosteroids in treating shock states, particularly in cases of the ARDS, may have a physiologic basis since very high concentrations of such drugs have been shown to inhibit both superoxide production and granulocyte aggregation.

[Clinical findings and trace metals (zinc & copper) in Leber's congenital amaurosis]

Sixteen (16) patients of Leber's congenital amaurosis diagnosed with ERG all had nystagmus since infancy; 9 cases showed the digito-ocular sign and 15 had axial hyperopia on cycloplegic refraction and/or A-scan ultrasonography. The common ophthalmoscopic findings were narrow vessels, grayish coloration and pigmentation in the retina. The average serum zinc level of 12 cases was significantly lower than that of the controls, while the copper level differed not much. The results suggest that it is advisable for the child patients to receive cycloplegic refraction and proper spectacle correction as early as possible, and zinc therapy.

[The effect of natural and artificial light via the eye on the hormonal and metabolic balance of man (author's transl)]

Examinations of hormone levels in blind persons compared with almost blind and people with normal vision and hormone evaluation with increased artificial light exposure show a definite stimulating effect of light on the human hormonal balance. The effect of light is mediated by an intact perception of light by the eye over an "energetic part" of the visual pathway (Hollwich 1948) - hypothalamus - hypophysis - peripheral endocrine gland. Increasing the intensity of artificial light with "neon-tubes" (fluorescent tubes) leads to "light stress" proved by increased hormone production - especially the stress hormone Cortisol. The belief that artificial light is the same as natural light and that it can fully replace it, is inappropriate in the medical view and needs correction.

Effects of biomarkers of oxidative stress damage on prevalence and severity of visual disability among black Central Africans

BACKGROUND

Because of the demographic transition, lifestyle changes, urbanization, and nutrition transition, Central Africans are at higher risk of ocular diseases associated with oxidative stress and visual disability. This study aimed to estimate the normal values of oxidant status defined by oxidized low-density lipoprotein (Ox-LDL), 8-Isoprostane and 8-hydroxy-deoxyguanosine (8-OHdG) and to determine their pathogenic role in the prevalence and the severity of visual disability among these black Africans.

METHODS

This was a cross-sectional study, run in a case-control study randomly selected from Kinshasa province, DR Congo. The study included 150 type 2 diabetes mellitus (T2DM) patients (cases) matched for sex and age to 50 healthy non diabetic controls. Logistic regression models were used to identify independent determinants of visual disability.

RESULTS

The presence rates were 8.5% for blindness, 20.5% for visual impairment and 29% for visual disability including blindness and visual impairment. After adjusted for taro leaves intake, red beans intake, T2DM, aging, waist circumference, and systolic blood pressure, we identified low education level (OR=3.3 95%CI 1.5-7.2; p=0.003), rural-urban migration (OR=2.6 95% CI 1.2-5.6; p=0.017), and high Ox-LDL (OR=2.3 95% CI 1.1-4.7; p=0.029) as the important independent determinants of visual disability. After adjusted for education, intake of red beans, intake of taro leaves, triglycerides, and T2DM, we identified no intake of safou fruit (OR=50.7 95% CI 15.2-168.5; p<0.0001), rural-urban migration (OR=3.9 95%CI 1.213; p=0.012), and high 8-OHdG (OR=14.7 95% CI 3.9-54.5; p<0.0001) as the significant independent determinants of visual disability. After adjusted for education level, no intake of red beans, no intake of Taro leaves, triglycerides, and T2DM, we identified no intake of Safou fruit (OR=43.1 95% CI 13.7-135.4; p<0.0001), age ≥ 60 years (OR=3.4 95% CI 1.3-9; p=0.024), and high 8-Isoprostane (OR=11 95% CI 3.4-36.1; p<0.0001) as the significant independent determinants of visual disability.

CONCLUSIONS

Visual disability remains a public health problem in Central Africa. Antioxidant supplement, fruit intake, nutrition education, control of migration, and blocking of oxidative stress are crucial steps for delayed development of vision loss.

Demonstration of pathological circulating endothelial cells in patients with amaurosis fugax

The present study was performed in nine patients with amaurosis fugax (AF). Eight of the patients had had at least one attack of AF in the preceding 3 months, and the ninth, a woman aged 35 years, had also had a transient cerebral ischaemic attack (TIA) 5 months previously, with residual hemiparesis. Only one patient, a man aged 51 years, had been given 'anti-platelet' therapy before beginning this study, having had a mycocardial infarct some years before. We suggest that AF is due to an embolism of platelet aggregates in the ophthalmic artery and that it is damage to the vascular endothelium which induces the platelet aggregation. In this study, we demonstrate by a simple technique an increased level of abnormal circulating endothelial cells in patients with AF.