In vivo analysis of chlorophyll a fluorescence induction

Quantitative characteristics of photosynthetic electron transport were evaluated in vivo on the basis of the multi-exponential analysis of OJIP fluorescence transients induced by saturating actinic light. The OJIP fluorescence curve F(t), measured in Chlamydomonas reinhardtii cells, was transformed into the (1 - F(O)/F(t)) x (F(V)/F(M))(-1) transient, which is shown to relate to PS 2 closure. We assumed that kinetics of PS 2 closure during OJIP rise reflects time-separated processes related to the establishment of redox equilibrium at the PS 2 acceptor side (OJ), PQ pool (JI), and beyond Cyt b/f (IP). Three-exponential fitting was applied to (1 - F(O)/F(t)) x (F(V)/F(M))(-1) transient to obtain lifetimes and amplitudes of the OJ, JI, and IP components of PS 2 closure, which were used to calculate overall rates of reduction and re-oxidation of the PS 2 acceptor side, PQ pool, and intermediates beyond Cyt b/f complex. The results, obtained in the presence of inhibitors, oxidative reagents, and under different stress conditions prove the suggested model and characterize the introduced parameters as useful indicators of photosynthetic function.

CLINICAL PHOTO-ATLAS Subconjunctival Haemorrhage (SCH)

No abstract available

New frequency/voltage converters for ac-electrogravimetric measurements based on fast quartz crystal microbalance

A better understanding of the mechanisms located at the solid/electrolyte interface is becoming essential to the development of new applications in the electrochemical fields. The fast quartz crystal microbalance is an attractive and powerful gravimetric sensor which can be used in the dynamic regime to determine a mass/potential transfer function. The principle is equivalent to classical electrochemical impedance measurements; the only difference is the determination of mass changes given by the quartz crystal microbalance rather than current changes following sine wave modulations of the applied potential. This function appears very well adapted to characterize ionic exchanges at the electrochemical interface. Frequency/voltage converters are the key devices in translating the microbalance frequency response in terms of a continuous voltage change. The latter allows the transfer function to be obtained via a frequency response analyzer. Different converters were tested in this work in order to improve the performances of the experimental setup.

Definition, classification and visual aspects of diabetes mellitus, diabetic retinopathy and diabetic macular edema: A review of literature

No abstract available

Short-term variation of autorefraction in Diabetic Macular Edema (DME) *

Very few studies have investigated autorefraction in diabetic subjects presenting either with diabetic retinopathy (DR) and/ or diabetic macular edema (DME). To the best of our knowledge this is the first study using multivariate methods for investigating short-term autorefraction in a small sample of subjects diagnosedwith DME. Forty consecutive autorefractor measurements were taken over a short interval on each of seven diabetic subjects with varying stages of DME, and the results were compared to a smaller group of four diabetic control subjects without DME (reasons for the differences in sample sizes will be explained later). Measurements were obtained from both the right and left eyes of all subjects.  Subjects in the two groups were similarly matched according to duration of diabetes mellitus (DM), age and glycated hemoglobin (HbA1c) values. Normality of data distribution was mostly achieved with the removal of outliers (where necessary) until profiles of skewness, kurtosis, and standard mean deviation exhibited near-normal distribution. Thereafter, stereo-pair scatter plots with 95% surfaces of constant probability density (distribution ellipsoids) were generated and compared between the experimental and control subjects.The diabetic subjects with DME demonstrated a larger spread of measurements in the eyes with the more severe DME, with the exception of one subject (subject 5). The volumes and orientation of the distribution ellipsoids also differed between the subject’s eyes. Some eyes with severe DME and poor visual acuitydisplayed more stigmatic variation (for example, subjects 2 and 4), while others (subjects 1 and 3) displayed more ortho-antistigmatic variation or near oblique antistigmatic variation (subject 7).  In all experimental subjects, with the exception of subject 5, the eye with the more severe DME had a larger distribution ellipsoidvolume, indicating greater variation in autorefraction and thus it might be surmised that this paper provides some preliminary data to suggest that diabetic subjects with DME display greater short-term variation of refractive behaviour when compared to diabetic subjects without DME. Secondly, in diabetic subjects withDME, eyes with the more severe DME or worse VA also display greater variation of refractive status. However, there seemed to be no distinctive or obvious pattern to the type of variation.In addition, a suitable statistic in terms of a Cubic Root Difference (CRD) was introduced in this study to compare inter-ocular ellipsoidal volumes. This statistic is also useful for comparing variances between eyes, or between means for groups of eyes, and could be used in studies involving anisometropia,  et cetera. Nevertheless, this study suggests that further investigation remains necessary before autorefraction can be used effectively in the early diagnosis, monitoring, and assessment of eyes with diabetic-related complications to the macular regions. 

A comparative study of autokeratometric and Scheimpflug keratometric measurements of the anterior corneal surface: results for a single subject

One purpose of the broader study was to determine whether keratometric measurements obtained with an autokeratometer (Nidek ARK-700) would be comparable with those measured using the Oculus Pentacam(model 70700). Ten healthy subjects without ocular abnormality, no previous or current contact lens wear or history of ocular surgery were recruited and at least 43 successive keratometric measurements were obtained for the right eye of each subject using both instruments, namely the autokeratometer and the Pentacam. This paper will concern itself with data from only one of the ten subjects involved, namely Subject 1. The corneal powers were analyzed using multivariate methods for analyzing dioptric power. Scatter plots and meridional profiles of skewness and kurtosis were used to compare the results for the two instruments. Mean dioptric powers in conventional and scientific notation were determined.The results for this subject indicated that there was a statistically significant difference between the autokeratometry and the Pentacam. Although the means  between the two instruments were found to be significantly different at a 95% level of confidence, there was minimal clinical difference between the means of the two instruments. That is, this preliminary investigation suggests that in normal eyes, clinically, keratometric results obtained by means of an autokeratometer and a Pentacam are reasonably similar and can be used interchangeably.

Anti-tumor activity of partially HLA-matched irradiated blood mononuclear cells in patients with advanced malignancies

2552

Background: We previously demonstrated the safety and efficacy of HLA-haploidentical blood mononuclear cells (MNCs) administered in the absence of preparative therapy to patients with metastatic renal cell carcinoma (RCC) (J Clin Oncol 21:3785–91.2003). The efficacy of this therapy is evaluated further in patients with advanced malignancies. Methods: Patients with advanced malignancies who had HLA- haploidentical donors were enrolled. Donors underwent 12–15 L leukapheresis. MNCs were processed by irradiation (25 Gy) and immediately infused. Disease evaluation was undertaken every 8 weeks. Repeat infusions were given every 8 weeks until disease progression. Results: 30 patients with diverse diagnoses, including 9 patients with a hematological malignancy were treated. Three of 13 patients with RCC had disease response, and 1 of 2 patients with melanoma had a mixed response. A patient with imatinib mesylate-refractory chronic myelogenous leukemia (CML) had a transient response. A patient with refractory acute myelogenous leukemia (AML) had disease response in conjunction with therapy. Treatment was associated with minimal toxicity and radiographic responses in patients with RCC did not occur until after 2–3 treatments. Host CD8+ cells reactive with the Pr-1 peptide of proteinase 3 were induced in association with disease response in a patient with AML. Additional studies identifying disease targets and mechanisms by which infusion of irradiated HLA-haploidentical cells are associated with disease response are ongoing. Conclusions: Disease response is seen with irradiated allogeneic MNCs administered outside the context of hematopoietic stem-cell transplantation. Evidence for anti-tumor activity is seen in isolated patients with RCC, melanoma, CML and AML. The temporal nature of the response in RCC in combination with the very limited survival of the infused cells raises the possibility of induction of a host-mediated anti-tumor effect. This hypothesis is supported by induction of host CD8+ T cells reactive with a tumor-associated peptide in a patient with AML. Given the lack of toxicity, broad availability of related haploidentical donors and the relative low financial cost, this form of cellular therapy should be developed further.

No significant financial relationships to disclose.

A phase I study of busulfan consolidation/intensification therapy for patients with high risk acute myeloid leukemia (AML)

6580

Background: Elderly AML patients have a poor prognosis. More effective well-tolerated treatments are needed to improve outcomes. Busulfan is an effective anti-leukemia drug commonly used in transplant regimens. We designed a phase I dose escalation study of single dose busulfan as consolidation/intensification therapy for elderly patients with AML. Methods: Patients in CR1 not candidates for transplantation or anticipated to benefit from high-dose cytarabine were enrolled. Cohorts were studied at 100mg/m2-120mg/m2, as a single oral dose of busulfan. The starting dose was based on a previous report (Ranson et al. Br J Haematol 79:162.1991). GM-CSF was started after busulfan until ANC> 2000/mm3. Dilantin was used for seizure prophylaxis. Results: 15 patients median age 71 (range 64–82) received treatment and are evaluable for toxicity, 14 are evaluable for response. No DLT was observed. Ongoing remission was seen in 3 patients (range 3 +- 7 + years). One patient (AML/MDS) was in remission for 52 months and died from small cell lung cancer and 1 patient was in remission for 15 months and died from cervical cancer. Two additional patients had prolonged remissions (32 and 55 months) prior to relapse. Seven patients relapsed between 4 weeks and 6 months. Treatment was well tolerated with no prolonged neutropenia. In patients who recovered without evidence of leukemia transient grade 3/4 thrombocytopenia occurred with average duration of 16 days (10–23 days) requiring 0–5 transfusions (average 2). Only 2 patients required RBC transfusion. No infectious complications or hospitalizations occurred in the absence of recurrent AML. Three patients experienced side effects from GM-CSF and received G-CSF in it’s place. Two patients experienced grade 2 fatigue and dyspnea. Conclusions: Single dose oral busulfan is an effective and well-tolerated outpatient consolidation/intensification therapy for patients with high-risk, AML. Prolonged remissions have been seen in 6 of 14 evaluable patients treated to date. Only transient bone marrow suppression requiring minimal transfusion support was seen. There were no hospitalizations or infections noted in patients without recurrent AML. The dose escalation will continue until MTD reached.

No significant financial relationships to disclose.

Ionized magnesium levels and the ratio of ionized calcium to magnesium in asthma patients before and after treatment with magnesium

OBJECTIVE

Prior studies have been equivocal about the efficacy of magnesium therapy in acute asthma exacerbations. We hypothesize that pretreatment ionized magnesium (Mg(2+)) levels and/or the ratio of ionized calcium to ionized magnesium (Ca(2+)/Mg(2+)) may have been confounding variables in these previous studies. Here, we report on the incidence of abnormal divalent ion levels in our asthma population.

MATERIAL AND METHODS

The study was designed as a randomized, double-blind, placebo-controlled trial of intravenous magnesium. Inclusion criteria were: age >18 years, percentage predicted forced expiratory volume (FEV(1)) <75 % after an initial beta-agonist. African-American patients (AA) at an urban university hospital were randomized to 2 g IV Mg or placebo. Mg(2+) and Ca(2+)/Mg(2+) levels were measured pre- and post-infusion. Data were reported as means+/-SD. Student's t-test and Fisher's exact test were used where appropriate (alpha = 0.05, two tailed).

RESULTS

Fifty-five AA patients (mean age of 42.7 years+/-15.6 years, range 18-75 years) were studied. A significantly (p<0.05) lower level of Mg(2+) was found in asthma (AS) patients compared with that in the AA group, by 0.03 mmol/L (95 % CI, 0.007-0.053 mmol/L). The AS group had a mean increase in Ca(2+)/Mg(2+) ratios over the AA group, of 0.27 (95 % CI, 0.16-0.38); 100 % of patients with abnormal divalent ion levels were corrected with IV magnesium.

CONCLUSIONS

We identified a subgroup of asthmatic patients with significant abnormalities in their divalent ion concentrations, which was corrected with IV magnesium.

Radioactive materials in biosolids: dose modeling

The Interagency Steering Committee on Radiation Standards (ISCORS) has recently completed a study of the occurrence within the United States of radioactive materials in sewage sludge and sewage incineration ash. One component of that effort was an examination of the possible transport of radioactivity from sludge into the local environment and the subsequent exposure of humans. A stochastic environmental pathway model was applied separately to seven hypothetical, generic sludge-release scenarios, leading to the creation of seven tables of Dose-to-Source Ratios (DSR), which can be used in translating from specific activity in sludge into dose to an individual. These DSR values were then combined with the results of an ISCORS survey of sludge and ash at more than 300 publicly owned treatment works, to explore the potential for radiation exposure of sludge workers and members of the public. This paper provides a brief overview of the pathway modeling methodology employed in the exposure and dose assessments and discusses technical aspects of the results obtained.

Error cells for spherical powers in symmetric dioptric power space

PURPOSE

: The purpose of this article is to analyze the geometry and examine the implications of the error cells of purely spherical powers in symmetric dioptric power space.

METHODS

: In the context of spherocylindrical data spherical data typically implies a cylindrical component that is less than some particular amount (often 0.125 D) in magnitude. This error or uncertainty in cylinder is over and above the error in sphere itself. The two components of error are used to define the error cells in symmetric dioptric power space.

RESULTS

: Error cells of spherical powers are constructed and presented as stereopairs. They are also shown in relation to error cells of powers in general.

CONCLUSIONS

: An understanding of error cells can help the researcher avoid pitfalls in the analysis of spherocylindrical data. Perhaps surprisingly, the error cells of spherical powers are not invariant under spherocylindrical transposition.

Book Review

No Abstract Available

Fundamentals of colour awareness: a literature review

A description of some of the basic or funda-mental aspects of the colour sensory mechanism will be provided here, based on modern ideas and literature, with reference specifically to the likely origins and evolution of colour vision.  The mo-lecular basis for colour awareness and the human colour pathway will also be considered in some detail. This paper intends to provide the theoreti-cal and philosophical basis for further papers that will introduce a modern and original computer- based  method  for  more  comprehensive  colour vision  assessment.    This  new  approach,  to  be fully described in later manuscripts, may contrib-ute towards improvements in understanding and knowledge of human colour perception and its measurement, still perhaps a relatively under-ex-plored or neglected field of study within optom-etry and ophthalmology.

Closed surfaces of constant visual acuity in symmetric dioptric power space

This paper demonstrates a multivariate approach to understanding the complicated relations of visual acuity to refractive state or ametropia. Other approaches, as previously used, included graphical representations of lines or profiles of iso-oxyopia (Peters, 1961). But one limitation of Peters' method is that cylinder axis was ignored. However, here the relationship between visual acuity and refractive power will be represented by estimated closed surfaces of constant visual acuity in symmetric dioptric power space. At or near the common center (of several closed surfaces, for example) is the refractive compensation. Coming outwards from such a center, the visual acuity drops in all directions in the space. The primary purpose of this paper was to present estimated closed surfaces of constant visual acuity for several eyes. Various procedures were performed on several subjects including measurement of iris aperture diameter, subjective refraction, and autorefraction. Thereafter, an automated phoropter and either Jackson cross-cylinders or spheres were used to influence dioptric blur or defocus in the subjects. The visual stimulus was a computer-generated nondirectional or meridionally independent letter O. Ovoidal surfaces fit the measurements obtained (with Jackson cross-cylinders and spheres) better than ellipsoidal surfaces. The cross-section, in symmetric dioptric power space, at powers with the same nearest equivalent sphere as the refractive compensation is elliptical in many cases and reflects a dependence of visual acuity on cylinder axis. The surfaces differ when powers are changed so that one is moving away from (decompensation surfaces) or toward (accompensation surfaces) the refractive compensation. The multivariate and graphical methods used in this paper probably have implications for the direction of future research in a number of areas involving measures of vision function such as autorefraction, retinoscopy, subjective refraction, and visual acuity.

Sertraline treatment of panic disorder: results of a long-term study

OBJECTIVE

To investigate the long-term efficacy, prevention of relapse and safety of sertraline in the treatment of panic disorder.

METHOD

This study consisted of 52 weeks of open-label sertraline treatment (n=398) followed by a 28 weeks of a double-blind, placebo-controlled discontinuation trial (n=183).

RESULTS

Ninety-three patients were randomized to sertraline and 90 were randomized to placebo. Discontinuation due to insufficient clinical response occurred in 23.6% of placebo-treated patients and 12.0% of sertraline-treated patients (log-rank test, P=0.040). Thirty-three per cent of placebo-treated patients had an exacerbation of panic symptomatology, versus 13% of sertraline-treated patients (log-rank test, P=0.005). Abrupt cessation of sertraline resulted in dizziness (4.3% sertraline vs. 16.9% placebo; P=0.007) and insomnia (4.3% sertraline vs. 15.7% placebo; P=0.013) occurring at significantly higher rates.

CONCLUSION

Long-term sertraline treatment was effective in preventing relapse of panic disorder, well tolerated and associated with minimal discontinuation symptoms.

New trends in regional anaesthesia

In this review, some of the newer developments in regional anaesthesia (RA) are discussed. The relationship between paraesthesiae and nerve stimulator responses has been shown to be unclear, and sometimes at a needle tip location where a paraesthesia is found, there is no response to the nerve stimulator. It is recommended to use whichever end point is found first. The debate as to the safety of RA in anaesthetised patients remains unresolved and strong opinions are often based on individual case reports. The training and skill of the anaesthetist still appears to be a more important factor. The problems of RA and impaired coagulation are well understood and guidelines are in place in many countries. The value of neuraxial blocks for postoperative pain management is well established and the increasing use of peripheral nerve blocks often using continuous methods is to be encouraged. The use of PCA for blocks as well as intravenously and the extension of the use of RA into the home are important developments. The beneficial effects of RA on postoperative morbidity and mortality are becoming clearer, and the introduction of the two new local anaesthetic agents, ropivacaine and levobupivacaine have improved safety. There has, however, been very slow progress in the development of long awaited ultralong acting local anaesthetics or in the introduction of slow release formulations.