Electrocardiographic findings of methanol toxicity: a cross-sectional study of 356 cases in Iran

BACKGROUND

Methanol is widely used in industry; however, methanol poisoning is not common. In this regard, a number of outbreaks have been recently reported due to inappropriate processing of alcoholic beverages. Shiraz, a city located in the southern part of Iran, faced one of such outbreaks in 2020 during COVID-19 pandemic. There is no sufficient literature on the electrocardiographic findings in methanol toxicity. This study aimed to address this gap in the literature.

METHOD

A total of 356 cases with methanol toxicity referred to Shiraz University of Medical Science Tertiary Hospitals (Faghihi and Namazi) in March and April, 2020. The clinical findings of blindness and impaired level of consciousness, lab data such as arterial blood gas, electrolytes, and creatinine, and the most common findings from ECGs were collected.

RESULTS

The most common ECG findings were J point elevation (68.8%), presence of U wave (59.2%), QTc prolongation (53.2% in males and 28.6% in females), and fragmented QRS (33.7%). An outstanding finding in this study was the presence of myocardial infarction in 5.3% of the cases. This finding, to the best of our knowledge, has only been reported in a few case reports. Brugada pattern (8.1%) and Osborn wave (3.7%) were the other interesting findings. In multivariate analysis, when confounding factors were adjusted, myocardial infarction, atrioventricular conduction disturbances, sinus tachycardia, and the prolonged QTC > 500 msecond were four independent factors correlated with methanol toxicity severity measured with arterial blood PH on arterial blood gas measurements, with odds ratios of 12.82, 4.46, 2.32 and 3.15 (P < 0.05 for all), respectively.

CONCLUSION

Electrocardiographic variations during methanol intoxication are remarkable and well-correlated with poisoning severity. Myocardial infarction was an egregious and yet a common concerning finding in this sample, which need to be ruled out in methanol toxicity.

Prognostic factors in methanol poisoning

The aim of this study was to assess the clinical and laboratory factors in methanol poisoned patients to determine the prognosis of their toxicity. This survey was done as a prospective cross-sectional study in methanol-poisoned patients in Loghman-Hakim hospital poison center during 9 months from October 1999—June 2000. During this time 25 methanol-poisoned patients were admitted. The mortality rate was 12 (48%). Amongst survivors, three (23%) of the patients developed blindness due to their poisoning and the other 10 (77%) fully recovered without any complication. The mortality rate in comatose patients was nine (90%) while in non-comatose patients it was three (20%) ( P < 0.001). There was a significant difference in mean pH in the first arterial blood gas of patients who subsequently died (6.82 ± 0.03) and survivors (7.15 ± 0.06) ( P < 0.001, M-W). The mean time interval between poisoning and ED presentation in deceased patients were (46 ± 15.7) hours, in survived with sequelae were (16.7 ± 6.7) and in survived without sequelae were (10.3 ± 7.2) hours ( P < 0.002, K-W). We found no significant difference between the survivors versus the patients who died regarding methanol. Simultaneous presence of ethanol and opium affected the outcome of the treatment for methanol intoxication favourably and unfavourably, respectively. In our study, poor prognosis was associated with pH < 7, coma on admission and >24 hours delay from intake to admission. Human & Experimental Toxicology (2007) 26: 583—586.

Homocysteine serum levels in diabetic patients with non proliferative, proliferative and without retinopathy

Homocysteine has been associated with extracellular matrix changes. The diabetic retinopathy is a neurovascular complication of diabetes mellitus and it is the leading cause of vision loss among working adults worldwide. In this study, we evaluate the role of homocysteine in diabetic retinopathy analyzing the plasma levels of homocysteine in 63 diabetic type 2 patients with nonproliferative retinopathy (NPDR), 62 patients with proliferative diabetic retinopathy (PDR), 50 healthy subjects used as control group, and 75 randomly selected patients.

A liver abscess deprived a healthy adult of eyesight: endogenous endophthalmitis associated with a pyogenic liver abscess caused by serotype K1 Klebsiella pneumonia

Klebsiella pneumonia usually causes urinary tract infections, pneumonia, and other infectious diseases in hospitalized and immunocompromised patients. Among the types of Klebsiella pneumonia, serotype K1 is known to be a highly virulent pathogen. We herein report the case of a healthy 63-year-old man with a pyogenic liver abscess and bilateral endogenous endophthalmitis caused by serotype K1 Klebsiella pneumonia. Although the patient received percutaneous abscess drainage and antibiotic therapy, he lost his eyesight. To improve the poor prognoses of ocular complications, providing both an earlier diagnosis and treatment is critical.

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.

Biological risk of older adults with visual impairments

OBJECTIVES

To investigate whether biological markers of health differ among older adults with visual impairment compared to those with normal vision.

DESIGN

We use data from the National Health and Nutrition Examination Survey (1999 - 2006) to investigate clinically defined at-risk levels for 10 biological markers.

SETTING

Survey participants were non-institutionalized.

PARTICIPANTS

Nationally representative (U.S.) sample of older adults age 65 and older, categorized as having blindness (20/200 or worse), low vision (20/40 to 20/100) or normal vision (better than 20/40).

INTERVENTION

Separate binary logistic regressions (one for each biomarker, with two at-risk cut points for BMI: obese and underweight) were computed to determine the odds of having at-risk levels of each biomarker.

MEASUREMENTS

Biomarkers included: systolic and diastolic blood pressure, high-density lipoprotein, low-density lipoprotein (LDL) cholesterol, total cholesterol, glycated hemoglobin, body mass index (BMI), fasting triglycerides, C-reactive protein, and plasma homocysteine.

RESULTS

Older adults who were blind were more likely to have high-risk levels of LDL cholesterol, homocysteine, and to be underweight (BMI>18.5). Similarly, older adults with LV were more likely to have high-risk levels of homocysteine compared to older adults with normal vision.

CONCLUSION

As several of the high-risk biomarkers associated with visual impairment were diet-related, our results suggest the importance of nutrition and diet programs aimed towards educating older people who are visually impaired.

Genetic analysis of Lrp5 function in osteoblast progenitors

The low-density lipoprotein receptor-related protein (Lrp)-5 regulates osteoblast proliferation and bone formation through its expression in duodenum by modifying the gut serotonin-bone endocrine axis. However, its direct role, if any, in osteoblast progenitor cells has not been studied thus far. Here, we show that mice with a Dermo1-Cre-mediated disruption of Lrp5 in osteoblast progenitor cells have normal embryonic skeletogenesis and normal skeletal growth and development postnatally. Histomorphometric analysis of 3-month-old adult mice revealed normal osteoblast numbers, bone formation rate, and bone mass in Lrp5(Dermo)(-/-) mice. In addition, analysis of two osteoporosis pseudoglioma (OPPG) patients revealed a three- to fivefold increase in their serum serotonin levels compared to age-matched controls. These results rule out a direct function of Lrp5 in osteoblast progenitor cells and add further support to the notion that dysregulation of serotonin synthesis is involved in bone mass abnormalities observed in OPPG patients.

Lingual infarction and sudden blindness due to giant cell arteritis

A 72-year-old woman suffered from giant cell arteritis (GCA) which developed into lingual infarction and monocular blindness. Temporary obscuration of vision and lingual symptoms such as increasing malaise, pain and intermittent claudication may precede the catastrophic results of arteritis. Emphasis is laid on early recognition and treatment of GCA.

Sudden-onset blindness in sickle cell disease due to retinal artery occlusion

Central retinal artery occlusion (CRAO) is a rare and potentially devastating cause of acute blindness in sickle cell disease (SCD) that is unique compared to classic sickle retinopathy. Few details related to this complication in SCD are known, including its risk factors, pathogenesis, presentation, treatment and outcomes. We present three patients with SCD and retinal artery occlusion. The overall variability in clinical presentation, treatment and prognosis reported in the literature underscores the need for a greater understanding of these factors as they relate to this complication in SCD.

Characterization of the IGF system in 15 patients with Alström syndrome

BACKGROUND

Alström syndrome (ALMS) is a rare recessively inherited progressive disease (OMIM 203800). Among its diverse spectrum of clinical features are phenotypes associated with deficiencies of the GH/IGF-I axis, including short stature, obesity, insulin resistance, hypertriglyceridaemia and heart failure.

PATIENTS AND MEASUREMENTS

To characterize the IGF system in ALMS, we evaluated a subset of 15 young adults with ALMS for hepatic, renal and thyroid function. Glycaemic and hormone measurements such as insulin, GH, FSH, LH, testosterone and 17-beta-oestradiol were clinically assessed. In addition, we measured IGF-I, IGF-II, IGF binding-protein-3 (IGFBP-3) and acid labile subunit (ALS - the subunits that constitute the main somatomedin complex in the circulation), and IGFBP-1 and IGFBP-2 (known to influence the bioavailability of the IGFs).

RESULTS

A significantly lower height was observed in ALMS patients compared to age-matched controls. ALMS patients were clinically obese (by weight and body mass index (BMI) standards) and leptin levels correlated with BMI. Renal and hepatic dysfunction was implicated in some patients by increased values of blood urea nitrogen (BUN) and creatinine, and transaminases, respectively. One-third of the patients presented with fasting hyperglycaemia and 80% were hyperinsulinaemic. TSH was slightly increased in 20% of patients. Baseline FSH and LH in females were within the normal range, while half of the males had abnormally low testosterone values. Male patients with hypogonadism showed significantly lower testosterone, oestrogen and ALS levels. Baseline GH values were not found to be increased. ALS and IGFBP-1 were significantly reduced and IGFBP-2 was markedly increased in ALMS patients compared to age-matched controls. The IGFs and IGFBPs were not significantly different between males and females affected with ALMS. No significant association was observed between IGFs or IGFBPs levels and weight, height, BMI, glycaemia, hyperinsulinaemia and testosterone levels. However, we found a significant association of gamma-glutamyltransferase (GGT) with IGFBP-2. IGF-I levels were significantly associated with LH in female patients.

CONCLUSIONS

In summary, the reduction of ALS and the increase of IGFBP-2 points to a growth hormone deficiency (GHD) condition in ALMS. However, further tests, including GH dynamics, are needed to determine whether, or to what degree disturbances in the GH/IGF axis contribute to the relatively short stature.

Melatonin and human chronobiology

With the development of accurate and sensitive assays for measuring melatonin in plasma and saliva, it has been possible to advance our understanding of human chronobiology. In particular, the dim light melatonin onset (DLMO) is expected to have an increasingly important role in the diagnosis of circadian phase disorders and their treatment with appropriately timed bright light exposure and/or low-dose melatonin administration. The phase angle difference (PAD) between DLMO and mid-sleep can be used as a marker for internal circadian alignment and may also be used to differentiate individuals who are phase advanced from those who are phase delayed (a long interval indicates the former and a short interval indicates the latter). To provide a corrective phase delay, light exposure should be scheduled in the evening and melatonin should be administered in the morning. To provide a corrective phase advance, light exposure should be scheduled in the morning and melatonin should be administered in the afternoon/evening. The study of patients with seasonal affective disorder (SAD), as well as individuals who are totally blind, has resulted in several findings of interest to basic scientists, as well as psychiatrists and sleep specialists.

Optic neuritis with residual tunnel vision in perchloroethylene toxicity

CASE REPORT

In a 57-year-old female owner of a dry-cleaning shop, we describe the association of severe bilateral optic neuritis with unexpectedly high concentrations of perchloroethylene/metabolites in the blood and of chloroform in urine. Visual disturbances consisted of complete blindness for 9 days in the left eye, for 11 days in the right eye, with bright phosphenes and pain on eye rotation. Only central (2-3 degrees radius) vision recovered in the following months.

CONCLUSION

Although environmental concentrations of perchloroethylene were within normal limits, we measured five-fold increases in vapors emitted when ironing freshly dry-cleaned fabrics, and suggest that inhalation of perchloroethylene vapors was the cause of this case of ocular nerve toxicity, recapitulating a previous report of major perchloroethylene toxicity.

The 14-year incidence of visual loss in a diabetic population

OBJECTIVE

The purpose of the study was to estimate the 14-year incidence of visual loss in a diabetic population and to examine its relationship to potential risk factors.

DESIGN

Cohort study.

PARTICIPANTS

A population-based sample of younger onset diabetic persons diagnosed younger than 30 years of age and taking insulin (n = 880) were examined at baseline, 4 years, 10 years, and 14 years.

INTERVENTION

Visual acuity (VA) as measured by the Early Treatment Diabetic Retinopathy Study protocol was performed.

MAIN OUTCOME MEASURES

Visual impairment (VI), defined as a VA of 20/40 or worse in the better eye; blindness, defined as a VA of 20/200 or worse in the better eye; and doubling of the visual angle were measured.

RESULTS

Cumulative 14-year incidences of VI, doubling of the visual angle, and blindness were 12.7%, 14.2%, and 2.4%, respectively. In univariate analyses, loss of vision as measured by doubling of the visual angle is associated with older age, longer duration of diabetes, higher glycosylated hemoglobin, higher systolic and diastolic blood pressure, presence of proteinuria, more pack-years smoked, presence of macular edema, and more severe retinopathy. In logistic regression analyses, incidence of doubling of the visual angle is associated independently with retinopathy (odds ratio [OR], 1.07; 95% confidence interval [CI], 1.03, 1.11 for each level), glycosylated hemoglobin (OR, 1.46; 95% CI, 1.28, 1.66 for each 1%), proteinuria (OR, 2.32; 95% CI, 1.39, 3.88 for presence), and age (OR, 1.45; 95% CI, 1.20, 1.75 for 10 years). In addition, a change in glycosylated hemoglobin from baseline to the 4-year examination is associated with loss of vision (OR, 1.15; 95% CI, 1.02, 1.30 for a 1% increase).

CONCLUSIONS

Loss of vision continues to be significant in persons with diabetes. These results suggest that prevention of retinopathy through control of glycemia will have a beneficial effect on visual outcome.

Nonphotic entrainment of the human circadian pacemaker

In organisms as diverse as single-celled algae and humans, light is the primary stimulus mediating entrainment of the circadian biological clock. Reports that some totally blind individuals appear entrained to the 24-h day have suggested that nonphotic stimuli may also be effective circadian synchronizers in humans, although the nonphotic stimuli are probably comparatively weak synchronizers, because the circadian rhythms of many totally blind individuals "free run" even when they maintain a 24-h activity-rest schedule. To investigate entrainment by nonphotic synchronizers, we studied the endogenous circadian melatonin and core body temperature rhythms of 15 totally blind subjects who lacked conscious light perception and exhibited no suppression of plasma melatonin in response to ocular bright-light exposure. Nine of these fifteen blind individuals were able to maintain synchronization to the 24-h day, albeit often at an atypical phase angle of entrainment. Nonphotic stimuli also synchronized the endogenous circadian rhythms of a totally blind individual to a non-24-h schedule while living in constant near darkness. We conclude that nonphotic stimuli can entrain the human circadian pacemaker in some individuals lacking ocular circadian photoreception.

Endocrine disorders in septo-optic dysplasia (De Morsier syndrome)--evaluation and follow up of 18 patients

Septo-optic dysplasia (SOD) is characterized by hypoplasia of the optic nerve, various types of forebrain defects and hormonal deficiencies. We have studied the clinical and endocrinological characteristics of 18 such patients retrospectively to: (1) better define the endocrine abnormalities in children with SOD; and (2) to find approaches for the interdisciplinary long-term care of children with SOD. The children were seen at the Children's Hospital of the University of Munich from 1976 to 1992 (8 boys, 10 girls; age at initial presentation: 1 day-13 years of age, mean 1.9 years). Unilateral hypoplasia of the optic nerve was found in 7 cases, bilateral hypoplasia in 11. Sonographic, CCT or MRI yielded the following results: 4 of the patients had a cavum septum pellucidum, 3 patients had hypoplasia of the cerebellum, 1 aplasia of the corpus callosum and 1 aplasia of the fornix. An empty sella with or without an ectopic pituitary was seen in 4 cases. Height standard deviation score (SDS) at time of diagnosis was -4.0 to +0.4, mean -2.92. Endocrine deficiencies were present in all 11 patients who had undergone endocrinological investigations. Seven patients suffered from isolated growth hormone (GH) deficiency or multiple hypopituitarism. One had diabetes insipidus centralis, 2 had hypogonadotropic hypogonadism, 1 had hypothyroidism and 2 adrenal insufficiency. Hypothalamic testing was performed only in a subset of patients: in 5 of 11 children tested a thyrotropin releasing hormone (TRH test), in two out of nine a gonadotropin releasing hormone (GnRH) test, and in three out of six GH releasing hormone (GHRH) test yielded abnormal results. High prolactin levels were measured in two out of five patients.

CONCLUSION

SOD is characterized by optic nerve hypoplasia and a variety of endocrine deficiencies. In addition, forebrain malformations are present in most SOD patients. Hormonal disorders are present in some SOD patients which may be of hypothalamic origin and need to be investigated systematically.

Melatonin and the pituitary-thyroid axis status in blind adults: a possible resetting after puberty

OBJECTIVE

Increased levels of free thyroid hormones have been previously described in prepubertal blind subjects and have been thought to be a consequence of a partial target organ refractoriness due to the early and prolonged lack of light perception. The aim of this study was to clarify whether this abnormality is permanent or transient and the interrelationships between melatonin and thyroid hormone secretion.

MEASUREMENTS

Total and free thyroid hormones, TSH, thyroxine-binding globulin (TBG), reverse triiodothyronine (rT3) and melatonin were measured in plasma samples obtained at 0800 h (two hours after lights-on) in a group of 11 totally (group 1) and 16 partially (group 2) blind adult patients and in 10 age-matched healthy subjects.

RESULTS

Both totally and partially blind patients showed melatonin levels higher than in controls (330 +/- 106 pmol/l, group 1 and 361 +/- 159 pmol/l, group 2, respectively; controls: 53 +/- 12 pmol/l, P < 0.001 vs both groups), but fT4, fT3, T4, T3 TSH, rT3 and TBG concentrations showed no significant differences from controls.

CONCLUSIONS

A possible resetting of pituitary-thyroid axis regulation can occur in blindness after puberty; variations of melatonin secretion could play a role in this. The inhibitory effect of melatonin on thyroid gland function found in animals does not seem to occur in humans. Elevated melatonin levels, both in patients with total blindness and in those with light perception only, suggest that more complex mechanisms other than light signalling are involved in the changes of melatonin secretion in blindness.

Effects of exposure to morning bright light in the blind and sighted controls

Seven blind subjects and 11 sighted controls were exposed to 3300 lux of cool-white fluorescent light for either 1 h or 15 min in the morning for 2 weeks during the winter. Serum 25-hydroxyvitamin D3 concentration, melatonin concentration in saliva, body temperature from the armpit, subjective sleepiness, and depressive symptoms were measured before and after the 2-week trial. The intervention resulted in a significant elevation in the concentration of melatonin at 21.00 hours in the healthy controls but at 23:00 hours in the blind subjects. The body temperatures measured were increased in the controls but decreased in the blind in the morning following the cessation of the intervention, and these opposite changes resulted in significant differences in the temperatures between the two groups. The decreases in the body temperature were associated with the increases in the levels of melatonin in the blind but not in the controls. Bright light administered in the morning decreased subjective sleepiness and improved mood in the healthy controls and in the blind subjects as well. The intervention had no effect on the levels of vitamin D in either of the two groups.

Normal plasma insulin-like growth factor I levels and impaired final stature in adult blind subjects

The aim of this study was to determine if changes in IGF-1 levels and in final stature occur in blind adult subjects. Eighteen subjects (4 females and 14 males) with total blindness (Group 1) and 26 subjects (5 females and 21 males) with only light perception (Group 2), living at an Institute for blind adult subjects in Naples, Italy, were studied. Their height and weight were compared to British standards. Plasma morning IGF-1 levels, measured by IRMA method were compared to those of 18 normal controls (6 females and 12 males) matched for age and weight. A high prevalence of short stature was demonstrated especially in Group 1 (p = 0.00005 by chi-square for trend test) but was also present in Group 2 (p = 0.02). No alterations in weight distribution were observed in both groups. Basal IGF-I levels in both Group 1 and Group 2 were similar to those of controls: IGF-1 (M +/- SE), 30.9 +/- 2.9 nmol/L and 37.9 +/- 2.7 nmol/L, respectively, vs 33.3 +/- 2.9 nmol/L, NS. High prevalence of final short stature in both groups confirms a negative influence of total or partial blindness on growth. These complex mechanisms appear to involve more than alterations in GH and IGF-I secretion.

[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.

Reduced increase in plasma renin activity on water-deprivation in blind hereditary microphthalmic rats

We compared the plasma renin activity (PRA) before and after 24-h water-deprivation in blind hereditary microphthalmic rats and Donryu rats. In the congenitally blind rats with a morphologically abnormal suprachiasmatic nucleus (SCN), hypovolemia induced significantly less elevation of the PRA and significantly more increase in the hematocrit value than in normal rats. The changes after water-deprivation in the blind rats were quite similar to those reported in rats with SCN lesions. However, the free-running circadian rhythms persisted in these blind rats, whereas those in rats with SCN lesions were completely eliminated. Thus, it is likely that SCN cells are involved in regulation of the PRA, and that if this is the case these cells are different from those containing the circadian pacemaker.

Blindness impairs plasma growth hormone response to L-dopa but not to arginine

To investigate how blindness influences GH secretion, we studied the GH response to L-dopa and arginine in 8 blind adult males and 10 normal age-matched control males. Arginine and L-dopa tests were performed in random order at least 1 week apart at 0800 h, and plasma GH was measured by RIA. The blind subjects showed GH responses to arginine similar to those in normal subjects [peak, 22.1 +/- 1.3 vs. 20.5 +/- 1.3 micrograms/L (+/- SE)], but their GH response to L-dopa was significantly reduced [peak, 5.4 +/- 1.3 vs. 20.3 +/- 2.4 micrograms/L (+/- SE); P less than 0.01]. Because L-dopa is believed to release GH by stimulating endogenous GHRH, whereas arginine may act by suppressing endogenous somatostatin secretion, we propose that blindness may impair GH release by inhibiting GHRH secretion.

Patterns of pineal melatonin secretion in rabbits: diurnal variation of basal and pulsatile release

The level and release pattern of plasma melatonin in the confluens sinuum of 28 sighted and 18 blinded (i.e. acute bilateral orbital enucleation) rabbits anesthetized with pentobarbital were studied. The animals had been adapted to a 12:12 h light-dark regime. Blood samples were collected from the cannulated confluens sinuum and/or the femoral artery at either 2- or 4-min intervals in both the light and dark phases. Plasma melatonin was determined by radioimmunoassay. In all rabbits studied, plasma melatonin in the confluens sinuum exhibited an episodic release pattern, with pulses superimposed on a basal level. At 4-min sampling intervals, the pulsatile release of melatonin in sighted rabbits were 3.8 peaks/h in the light phase; shorter sampling interval (2-min) revealed more frequent pulsatile release of melatonin (5.1 peaks/h). In sighted animals in the light phase, the level of melatonin in the plasma of confluens sinuum was 7-15 times higher than that obtained from the plasma collected at the same time from the peripheral artery where the level of melatonin also exhibited pulsatile pattern. In blinded animals, melatonin levels in terms of mean concentration, mean maximum level and mean minimum (or baseline) level obtained in the dark phase were 12-14 times higher than those obtained in the light phase. These results suggest that the level of melatonin exhibits a diurnal rhythm in the confluens sinuum of rabbits.

[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.

Acute promyelocytic leukemia presenting as sudden blindness and sinus vein thrombosis

An 11-year-old boy was hospitalized with sudden blindness and sagittal sinus vein thrombosis, which were the presenting signs of acute promyelocytic leukemia (APL). The association of disseminated intravascular clotting (DIC) with APL is well-known, and DIC usually affects the smaller blood vessels. The obliteration of a large blood vessel, as in our case, is an uncommon manifestation of DIC. This presentation of acute childhood leukemia is unusual and, to the best of our knowledge, has not been previously reported.

Plasma thyrotropin, thyroxine, triiodothyronine, free thyroxine, free triiodothyronine, and cortisol levels in blind prepubertal boys

Findings on thyroid function in blind subjects are lacking. The aim of this study was to investigate the thyroid hormonal pattern in prepubertal blind subjects. Six healthy and 8 blind males, aged 7-10 yr, in Tanner stage one puberty, living at Institute "Martuscelli" for blind young subjects, Napoli, Italy, were studied. Each had a TRH (200 micrograms) test at 08:00 h after nocturnal rest. Plasma TSH, T4, T3, free T4(FT4), free T3(FT3) and cortisol (F) were measured by RIA. Our blind subjects show levels of TSH (basal values and absolute peak after TRH), T4, T3 and F normal but FT4 levels significantly higher than controls (39 pg/ml +/- 4.7 vs 12 +/- 0.6, p less than 0.001; 14 pg/ml +/- 1.3 vs 4.7 +/- 0.2, p less than 0.001, respectively). Our results, similar to those found in some patients with euthyroid hyperthyroxinemia, suggest that the prolonged inability to receive light signal could influence the metabolism of thyroid hormones and/or cause a tissue resistance to their action, even if this hypothesis must be verified by future more extensive investigations.

Little or no induction of hyperglycemia by 2-deoxy-D-glucose in hereditary blind microphthalmic rats

Studies were made on whether hereditary microphthalmic rats (1), which are congenitally blind, showed a hyperglycemic response to intracerebroventricular injection of 2-deoxy-D-glucose (2DG) in their subjective light period. In contrast to previous findings in normal rats in which 2DG injection caused light-cycle dependent hyperglycemia (2) and bilateral lesion of the suprachiasmatic nucleus (SCN) completely abolished this hyperglycemia (3), 2DG injection caused no and only slight hyperglycemia in male and female rats with hereditary microphthalmia, respectively. Gross and histological examinations indicated that these rats had no optic nerve or retinohypothalamic tract and that their SCN had an abnormal structure. Locomotive activity recordings showed that all the blind rats had a free-running circadian activity rhythm. These findings suggest that the projection sites of the retinohypothalamic tract to the SCN are involved in the mechanism of the hyperglycemic response to 2DG, but that neural cells, which may be responsible for the generation of circadian rhythms, are not. We have reported that when adult rats were blinded by orbital enucleation, their hyperglycemic response to 2DG was suppressed temporarily 3-5 weeks after the operation, but that their plasma insulin level was basically higher and increased further after 2DG injection during this period (4). In congenitally blind rats, however, the basal plasma insulin level was not higher and the level did not change after 2DG treatment. This difference is discussed from the view point of the role of the premature SCN in regulation of the plasma insulin concentration.

Temporary suppression of the hyperglycemic response to 2-deoxy-D-glucose by blinding

Studies were made on whether there is a time-dependency in the hyperglycemic response to intracranial injection of 2-deoxy-D-glucose (2DG) in blind rats. 2DG was given to blind rats in their subjective light and dark periods to see if the response free-runs like their circadian locomotor and feeding rhythms. The following results were obtained: (1) In control period and week 3 after blinding, 2DG caused greater hyperglycemia in the subjective light period than in the subjective dark period; (2) In weeks 4 and 6, however, 2DG caused only slight hyperglycemia, while it caused considerable hyperinsulinemia in both the subjective light and dark periods with no time-dependency. (3) In week 8, the hyperglycemic response to 2DG was completely restored while the hyperinsulinemic response was lost. These findings indicate that the subjective time-dependency in the hyperglycemic response to intracranial injection of 2DG exists until week 3 and after week 8 after blinding, however, in week 4 and 6 after blinding the subjective time-dependency appeared to disappear and the hyperglycemic response is largely suppressed in association with hyperinsulinemia. Together with a previous finding that bilateral lesions of the SCN completely abolished the response to 2DG and the fact that blind rats showed circadian rhythms of feeding and locomotive activity even in weeks 4 and 6 after blinding, these findings present the possibility that the site responding to 2DG is in the vicinity of the SCN, but is in different neuronal cells from those of the circadian oscillator. However, it is also possible that the blinding elicits the suppression of hyperglycemia due to 2DG through disturbing neural pathway outside the SCN which control blood glucose concentration.

Influence of blindness on plasma luteinizing hormone, follicle-stimulating hormone, prolactin, and testosterone levels in prepubertal boys

The aim of this study was to determine if changes in LH, FSH, PRL, and testosterone (T) secretion occur in blind prepubertal boys. Eight blind and six normal boys, aged 7-10 yr, living at an institute for blind subjects in Naples, Italy, were studied. Each had a combined GnRH (100 micrograms) and TRH (200 micrograms) test at 0800 h after nocturnal rest. Plasma LH, FSH, PRL, and T levels were measured by RIA. The blind boys had basal plasma LH, FSH, and T levels significantly lower than those in the normal boys (P less than 0.01 for all three); plasma PRL basal levels were similar to those in the normal boys. The blind boys, moreover, had lower peak LH, FSH, and PRL (P less than 0.01 for all three peaks) levels in response to GnRH-TRH. Our results, similar to those found by others in patients with delayed puberty or with hypogonadotropic hypogonadism, suggest that light stimuli influence neuroendocrine-gonadal activity in humans, as in other mammals; and in blind prepubertal boys, impaired hormone secretion could cause a delay of pubertal development or more severe hypogonadism.

Amaurosis fugax under the age of 40 years

Sixteen patients who presented under the age of 40 years with amaurosis fugax have been studied. Follow up from the time of presentation was one to 13 years with a median of 3 years. One patient whose attacks of uniocular visual loss were associated with headache developed a permanent uniocular field defect. None of the other patients has suffered permanent visual loss, or had symptoms of cerebral or myocardial ischaemia. All angiograms were normal and it is suggested that carotid angiography is unnecessary in this age group. Four out of ten patients studied demonstrated evidence of platelet hyperaggregability to low concentrations of arachidonic acid and adenosine diphosphate with spontaneous aggregation. However, in six patients treated with aspirin, including three with previous platelet hyperaggregability, there was no change in the frequency of their attacks implying that the observed platelet abnormalities were not the cause of the amaurosis fugax.

Leber's congenital amaurosis associated with hyperthreoninemia

Two siblings had Leber's congenital amaurosis. The girl (Patient 1) showed blindness shortly after birth, absent pupillary light reflex, and multiple round, white spots in both fundi. Her serum threonine level was increased (2.0 to 5.3 mg/dl; normal, 0.78 to 1.82 mg/dl). She died of massive pericardial effusion four months after birth. Her brother (Patient 2) was nearly blind shortly after birth. He had a poor pupillary light reflex and a nearly extinguished electroretinographic response. He also had hyperthreoninemia, hyperthreoninuria, hepatomegaly, and mental and physical retardation. We suspect a close relationship between hyperthreoninemia and Leber's congenital amaurosis in these siblings.

The influence of blinding, olfactory bulbectomy, and pinealectomy on twenty four-hour plasma prolactin levels in normal and neonatally androgenized female rats

The influence of blinding (BLD), olfactory bulbectomy (ANOS), and pinealectomy (PX) on 24-h plasma PRL levels was examined in normal and neonatally androgenized (NA) female rats. NA pups were treated at 3 days of age with 1.25 mg testosterone propionate. Surgery was performed on both NA and normal animals at 22-25 days of age. At 10 weeks of age, animals were vaginally smeared, and at 15 weeks, they were ovariectomized, injected with 0.5 mg polyestradiol phosphate, and fitted with atrial catheters for blood sampling. At 16 weeks of age, blood samples were taken over a 24-h period. In normal animals, BLD plus ANOS resulted in half of the animals exhibiting a diestrous vaginal smear, while the other half exhibited at least one vaginal estrus during the 7-day period when vaginal smears were obtained. Ovarian, oviductal, and uterine weights for blinded (BLD) plus olfactory bulbectomized (ANOS) animals exhibiting diestrous smears were significantly less than those of BLD plus ANOS animals exhibiting periodic vaginal estrus. Plasma PRL levels were lower in both animal groups compared with those in sham controls, but BLD plus ANOS animals with small ovaries had significantly lower plasma PRL and BLD plus ANOS animals with large ovaries. PX of BLD plus ANOS animals resulted in endocrine organ weights comparable to those in controls and elevated the plasma PRL levels to those observed in BLD plus ANOS animals with large ovaries. The PRL levels in BLD, ANOS, and pinealectomized animals, however, were still below those in sham control animals. Sensory deprived animals had peak PRL values at various times of day, and regrouping of the data from the peak PRL time for each animal suggested the presence of a free-running plasma PRL rhythm. In NA animals, a decrease was also observed in endocrine organ weights and plasma PRL for BLD plus ANOS animals similar to that observed for normal BLD plus ANOS animals. However, all animals in the NA BLD plus ANOS group responded with a constant diestrous smear, small ovaries, and low plasma PRL values. PX prevented the decrease in endocrine organ weights and plasma PRL observed in BLD plus ANOS animals. As in normal animals, NA animals also exhibited a free-running PRL rhythm when sensory deprived.(ABSTRACT TRUNCATED AT 400 WORDS)

Use of tactile techniques for self-monitoring of blood glucose in visually impaired patients with diabetes mellitus

Twenty-eight patients with type I diabetes mellitus, legally blind as a result of proliferative retinopathy, were recruited into a program designed to teach and evaluate tactile methods for self-monitoring of blood glucose (SMBG). Vision ranged from "blind" to "able to read large print." Techniques with wipe-off strips (Chemstrip bG or BM Test BG, Boehringer-Mannheim, Canada Ltd., Dorval, Quebec, Canada) use the opposite hand as a guide, operation of timing devices by touch, and special methods for labeling and storing strips. Methods with wash-off strips (Dextrostix, Ames Division, Miles Laboratories, Rexdale, Ontario, Canada) employ the fingers as a guide in directing the wash water. The accuracy of tactile methods was documented. Clinical parameters of glucose control improved in patients with adequate data after 6 mo of tactile SMBG. Glycosylated hemoglobin in 17 patients decreased from 11.3 +/- 2.1% to 9.4 +/- 1.5% (P = 0.005). Patients experienced significantly fewer reactions and low blood sugar readings as well as lowering of mean blood glucose values from 158 +/- 56 to 141 +/- 51 (P = 0.025).

Coincidence of counter-antigonadal and counter-antithyroid action of melatonin administration via the drinking water in male golden hamsters

Administration of melatonin via the drinking water prevented the gonadal involution and the thyroid hormone depletion normally observed in blinded hamsters. Ten weeks after blinding male hamsters had plasma thyroxin levels that were 57% of controls and testis weights that were 8% of controls. Administration of melatonin (80 microgram melatonin/ml drinking water) to blinded hamsters restored thyroxin levels to 86% of controls and testis weights to 93% of controls. Dose response data showed that as little as 1.25 microgram (approximately 10 microgram/hamster/day) produced a significant effect on testis weight, whereas the lowest dose required to produce a significant increase in thyroxin levels was 10 microgram/ml. The coincidence of counter-antigonadal and counter-antithyroid actions of melatonin suggests a single site of action.

Entrainment of the circadian rhythms of blinded infant rats by nursing mothers

New-born rats were optically enucleated on day 1 and the rhythms of pineal serotonin N-acetyltransferase activity and serum corticosterone levels were followed under various nursing schedules from 4 to 8 weeks of ages. When blinded pups born under DL (LD) cycle were reared by foster mothers under LD (DL) cycle, both of N-acetyltransferase and corticosterone rhythms were in phase with those of the pups born of and reared by their original mothers under LD (DL) cycle. The phases of the rhythms were regularly delayed at a similar rate in 4 groups as they grew, indicating that nursing mother rats can entrain the circadian rhythms of blinded pups. When intact and blinded pups were reared under LD cycle, the phases of N-acetyltransferase activity rhythm in both groups were identical at the first postnatal week, but the phase of the rhythm in blinded pups was gradually delayed after second week compared to intact pups. The observation indicates that the endogenous oscillation in blinded pups starts to free-run between 1 and 2 weeks after birth.

Effects of light on human melatonin production and the human circadian system

Bright artificial light appears to have similar effects in humans as in other species. Bright light may therefore be used as a clinical research tool and as a therapeutic modality for treating certain biological rhythm disorders. Melatonin production appears to be a particularly useful "biological marker" for the human endogenous circadian pacemaker and the effects of light.

Effects of change of mothers and lighting conditions on the development of the circadian adrenocortical rhythm in blinded rat pups

Free-running blood corticosterone rhythms were examined between the 4th and 9th postnatal week in blinded rat pups optically enucleated on day 1. The pups were born of mother rats having a free-running rhythm under constant illumination conditions and then were put under two separate illumination conditions (light - dark cycle and dark - light cycle) under the care of foster mothers already synchronized to each respective condition. Despite being born of the same mother rat, when the pups were raised by a mother with a different rhythm from that of the natural mother, they showed a different phase from that of the pups raised by the natural mother. Furthermore, each possessed different phase angles, depending on the rhythm of their respective foster mothers. On the other hand, although the rhythm of the natural mothers differed, when the rhythms of the nursing mothers were the same after birth, the blinded pups showed similar phase angles during the observation periods. These data suggested that the blinded pups were not affected by the rhythm of the natural mothers but rather showed a phase angle in accordance with the rhythm of the nursing mother.

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.

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.

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.

[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.

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.