Two Eyes Are Better Than One—Binocular Summation of Dark Vision in Healthy Individuals and Patients with Chronic Respiratory Disease

We compared monocular and binocular absolute thresholds of dark adaptation in two separate study populations. Eighteen healthy individuals (Group A) and 13 patients with chronic respiratory insufficiency (Group B) were examined three times each by computerised dark adaptometry with simultaneous but separate recordings from each eye and binocularly. The respiratory patients received oxygen supplement at visits 1 and 3. In Group A, at all three visits, binocular dark adaptation was significantly more sensitive (40.5%) than monocular dark adaptation with either eye. In Group B, at visits 1 and 3, binocular dark adaptation was also significantly more sensitive than monocular dark adaptation (40.5% higher than the right and 47% higher than the left eye). However, in Group B, at visit 2 without oxygen treatment, no significant differences were observed between monocular and binocular sensitivities. Binocular dark vision was superior to monocular dark vision in healthy individuals and in patients with respiratory insufficiency that were provided oxygen supplementation. Furthermore, deficit in oxygen seems to affect binocular summation, perhaps by impaired enhancement in the central nervous system.     

Ocular vasodynamic changes in light and darkness in smokers

PURPOSE: To determine whether smokers have a reduced capacity for increased retinal blood flow velocity in darkness. METHODS: The peak systolic flow velocities (V(S)) and end diastolic flow velocities (V(D)) were measured by ultrasound (i.e., color Doppler equipment), in light and darkness in the ophthalmic and central retinal arteries in 20 cigarette smokers and 20 matched nonsmokers. The resistive index (RI) was calculated as RI = (V(S) - V(D))/V(S). RESULTS: In the ophthalmic artery in nonsmokers, the V(D) was markedly increased in darkness and the RI was correspondingly reduced. After the subject was re-exposed to light, the RI was markedly increased. In smokers the V(S) and V(D) did not change significantly in the different conditions of light and darkness. In the central retinal artery in nonsmokers, the V(S) and V(D) were markedly increased in darkness and decreased after re-exposure to light. In smokers, the corresponding changes were much smaller and not significant. CONCLUSIONS: The normal capacity for increased blood flow velocity in the central retinal artery in darkness was markedly reduced in smokers. This finding may explain the reduced dark vision after recent smoking reported in several studies and probably reflects the combined effects of an increased blood viscosity, the vasoconstrictive action of nicotine, and a reduced capacity of the blood to transport oxygen, as the hemoglobin is partly occupied by carbon monoxide.     

Impaired dark adaptation in polycythemia. Improvement after treatment

PURPOSE: To determine if dark adaptation is reduced in individuals with polycythemia and if so whether there is any improvement in dark adaptation after treatment. METHODS: Dark adaptation was recorded monocularly by automatic dark adaptometry in ten consecutive patients with polycythemia before and after treatment. Analogue investigations were performed in 31 healthy control subjects. RESULTS: Dark adaptation was markedly impaired in the patients as compared with the control subjects. After reduction of the red cell count and normalization of the hematocrit and hemoglobin the dark adaptation was markedly improved. There was no significant change in dark vision in the control subjects negating a confounding learning effect. CONCLUSION: The findings indicate a sustained but reversible neuronal hypofunction secondary to polycythemia. As the rheological abnormality was normalized, dark adaptation was improved, probably secondary to normalized microcirculation within the retina or the brain, or both, possibly with reactivation of formerly inactive neuronal cells.     

A Horner-like syndrome and cluster headache. What comes first?

PURPOSE: To evaluate if an ocular sympathetic lesion may be a prerequisite for cluster headache to occur. METHODS: Patients with a permanent Horner-like syndrome at the debut of cluster headache were identified from history and photographs. RESULTS: Among 57 patients with cluster headache, seven patients (5 males and 2 females) exhibited a permanent Horner-like syndrome on the painful side when first seen at the outpatient department. During this study it was possible to get information from six of these patients and five of them had side constant cluster headache. In retrospect, these five patients had had a Horner-like syndrome for years prior to the onset of ipsilateral cluster headache. CONCLUSION: The findings indicate that a sympathetic lesion or dysfunction may be a prerequisite for the subsequent development of cluster headache.     

Nitric oxide in patients with chronic liver diseases

AIM: Chronic liver disease (CLD) may be accompanied by portal hypertension (PHT). Nitric oxide (NO) system disturbances seem to play a key role in the pathogenesis of CLD and PHT. In this study we aim to assess if in chronic active hepatitis (CAH) and cirrhosis (CIR), CLD severity and etiology can be correlated with the serum level of NO metabolites. METHOD: The study was performed on 92 patients divided according to the diagnosis and Child-Pugh class, and a control group of 10 healthy volunteers. Serum nitrite/nitrate and citrulline levels were measured in order to evaluate NO synthesis. RESULTS AND CONCLUSION: In CLD patients there was an increased NO production. In CIR NO synthesis increased more than in CAH. In CIR patients only nitrite/nitrate concentrations were correlated with citrulline levels. NO metabolites from CAH and CIR patients varied according to disease etiology, namely NO synthesis was more important in HCV-CLD than in alcoholic-CLD and HBV-CLD. In CIR patients, NO metabolites level increased with disease severity.     

Reversibility of neurological deficits in vitamin B12 deficiency

Summary A female patient with subacute neurological deficits secondary to an hereditary vitamin B₁₂ deficiency was repeatedly examined clinically and neurophysiologically. It is concluded that neurological normalization after treatment with vitamin B₁₂ also occurs within the CNS. Such normalization takes place soon after initiating treatment and probably reflects other neuronal mechanisms than remyelination, i.e. recovery from conduction block in fast somatosensory pathways and/or improvement of synaptic transmission.     

放疗后癌症患者淋巴细胞微核持续存在的意义(英文)

目的　验证以周围血淋巴细胞 (PBL)的微核率作为定量的生物照射剂量指标对监测体内照射性损害的实用性。方法　应用细胞因子阻滞的微核法测定人体部分放疗患者 (13例 )PBL中的微核率 ,以照射剂量测定法的数据表示不同范围的照射次数、肿瘤累积剂量、总积分剂量和等值总体吸收剂量。结果　这些患者的PBL中微核率随等值总体吸收剂量增加而增加 ,呈线性分布 ,并明显偏离普哇松分布 ;PBL的微核率随随访时间增加而普遍下降 ,下降率呈线性分布并与等值总体吸收剂量相关 (r =0 .7,p=0 .0 0 7) ,微核率的降低在不同个体有很大差异 ;9例患者在初次放疗后至少 4 8个月 ,PBL微核率高于相应的放疗前的水平 ,表明放疗诱导残留的细胞遗传学损害持续存在。结论　人类微核率为评价体内放射剂量提供一个可靠的生物学剂量指标 ;放疗结束后 ,升高的PBL微核率持续存在是放射诱导畸变细胞部分残留的一种反映     

Antimicrobial properties of human dentin impregnated with tetracycline HCI or chlorhexidine

Abstract Substantivity of tetracycline HCI and chlorhexidine digluconate to human root dentin was assessed in vitro. 51 extracted single-rooted teeth, their crowns removed, were assigned to 1 of 4 treatments in groups of 12. A control groups included 3 roots. Each group was divided into 3 subgroups to allow evaluation of drug exposure for 1, 3 or 5 min. The roots were immersed in tetracycline HCI (10 or 50 mg/ml) or chlorhexidine digluconate (0.12 or 0.2%) solutions following root planing. Control roots were immersed in sterile saline (0.9%). Following drug immersion, the roots were transferred to tubes containing 2 ml tris buffered saline. The tubes were incubated at room temperature for 22 days. Desorption media were replaced at 24-h intervals. Removed media were examined for antimicrobial activity using a microtiter assay in which bacterial growth was evaluated by optical density readings. Roots immersed in tetracycline HCl 50 mg/ml released antimicrobial activity to successive desorption media for 14 days. Tetracycline HCl 10 mg/ml activity lasted 4 days. Roots subjected to chlorhexidine digluconate released antimicrobial activity for 24 h only. Within each treatment, there were no differences between the 3 exposure intervals of 1, 3 or 5 min. Our findings suggest usage of the periodontally exposed instrumented root as a depot for sustained release of tetracycline HCI, but not chlorhexidine digluconate, to the subgingival environment. The substantiveness of tetracycline HCI seems related to drug concentration rather than the exposure interval. Clinical trials are needed to confirm the clinical significance of these in vitro observations.     

Cluster Headache in Two Sisters. Pupillary Response to Phenylephrine and Tyramine

Two sisters with cluster headache were studied with respect to the pupillary responses to instillation into the conjunctival sac of a single drop of a 1% solution of phenylephrine and a 2% solution of tyramine. The changes in pupillary diameters were documented by photographic pupillometry prior to and at 15, 30, 60, and 90 minutes after the instillations.
Of the two sisters, one (case A) was examined during a symptom-free interval, when she had been free from cluster headache attacks for 2 1/2 years. When the cluster headaches recurred, retesting was performed. The other sister (case B) had been free from cluster headaches for 9 years, when she was examined.
The findings indicate hypofunction within the postganglionic sympathetic nerve fibers during a cluster headache period. The hypofunction is bilateral, and thus, can not be a consequence of the unilateral cluster headache attacks. During remissions, tyramine induces a marked mydriasis, particularly on the symptomatic side, tentatively indicating an excessive release of stored monoamines.