Phase-sensitive imaging of the outer retina using optical coherence tomography and adaptive optics

The cone photoreceptor's outer segment (OS) experiences changes in optical path length, both in response to visible stimuli and as a matter of its daily course of renewal and shedding. These changes are of interest, to quantify function in healthy cells and assess dysfunction in diseased ones. While optical coherence tomography (OCT), combined with adaptive optics (AO), has permitted unprecedented three-dimensional resolution in the living retina, it has not generally been able to measure these OS dynamics, whose scale is smaller than OCT's axial resolution of a few microns. A possible solution is to take advantage of the phase information encoded in the OCT signal. Phase-sensitive implementations of spectral-domain optical coherence tomography (SD-OCT) have been demonstrated, capable of resolving sample axial displacements much smaller than the imaging wavelength, but these have been limited to ex vivo samples. In this paper we present a novel technique for retrieving phase information from OCT volumes of the outer retina. The key component of our technique is quantification of phase differences within the retina. We provide a quantitative analysis of such phase information and show that-when combined with appropriate methods for filtering and unwrapping-it can improve the sensitivity to OS length change by more than an order of magnitude, down to 45 nm, slightly thicker than a single OS disc. We further show that phase sensitivity drops off with retinal eccentricity, and that the best location for phase imaging is close to the fovea. We apply the technique to the measurement of sub-resolution changes in the OS over matters of hours. Using custom software for registration and tracking, these microscopic changes are monitored in hundreds of cones over time. In two subjects, the OS was found to have average elongation rates of 150 nm/hr, values which agree with our previous findings.     

Transient splenial lesion of the corpus callosum in clinically mild influenza-associated encephalitis/encephalopathy

BACKGROUND: Reversible lesions in the splenium of the corpus callosum (SCC), caused by various agents such as influenza, rotavirus, Escherichia coli, mumps, and adenovirus, were previously defined in a handful of cases. We present 5 cases with transient diffusion restriction of the SCC associated with influenza A virus infection. MATERIALS AND METHODS: Five patients with influenza-associated encephalitis/encephalopathy and sudden-onset neurologic symptoms following a prodromal flulike episode were examined by MR and diffusion-weighted imaging (DWI). RESULTS: Three patients, who had drowsiness and new-onset convulsions, recovered spontaneously without any medication. In the other 2 seizure-free patients, 1 had trigeminal neuralgia and headache and the other had facial numbness and left upper monoparesis. All patients had round well-defined ovoid hyperintense splenial lesions (14.94 +/- 1.87 mm) on DWI with a significantly low apparent diffusion coefficient (ADC) of 0.41 +/- 0.05 x 10(-3) mm(2)/s compared with 0.84 +/- 0.01 x 10(-3) mm(2)/s of normal-appearing white matter. In the patient with a motor deficit, additional lesions were found in the cerebral deep white matter. The high signal intensity of the splenial and deep white matter lesions on DWI completely disappeared on follow-up studies, and ADC values also improved, returning to those of normal-appearing white matter on days 8-11. Clinically, all patients completely recovered on days 4-9. CONCLUSION: A transient lesion of the SCC is a significant but nonspecific finding. It is probably due to edematous and/or inflammatory changes of the SCC. It may be the only detectable change in patients with good prognosis, indicating a clinically mild form of encephalitis/encephalopathy.     

Arthroscopic repair of radial lateral meniscus [corrected] tear by double horizontal sutures with inside-outside technique

The purpose of this prospective study is to report the outcome of arthroscopic repair of radial lateral menicus tears at the junction of the anterior horn and body. Five patients with an average age of 27 years were treated. The repair was performed with double horizontal sutures by inside-out technique, using zone-specific, curved cannulae with no enhancement technique. A mean of 2.4 superior and 2.8 inferior stitches were performed. Reduction was obtained in all cases. Patients were evaluated using Lysholm functional knee scores. All patients were clinically and radiologically examined using MRI to assess meniscus integrity at the repair site, over an average follow-up period of 31 months. All patients were able to return to their former level of activity. In all cases, MRI showed a fully healed meniscus at the repair sites, with no further disruption of the debrided area. The mean Lysholm scores improved from 62 preoperatively to 94 postoperatively. The difference between preoperative and postoperative values was found to be statistically significant (p=0.029). No cases of postoperative extra or intra-articular complications were encountered. We found that repairing rather than resecting radial lateral menicus tears that extend into capsular zone, improves activity level.     

Obstructive rectal intramural hematoma caused by a foreign body

Intramural hematoma of the alimentary tract is a rare condition, which usually results from blunt injury. It can spontaneously occur in patients with coagulopathy or on anticoagulants. Although it may be seen anywhere in the alimentary tract, duodenum is the most common site of the intestinal intramural hematomas. Intramural hematoma caused by a foreign body is rarely seen. Patients with intramural hematoma are usually encountered with obstructive symptoms after an isolated injury. Intramural hematomas are often self-limited at the site of occurrence and can be managed conservatively. They rarely cause progressive obstruction and need surgical drainage. In this article, we report a 51-year-old male patient with foreign body used for masturbation causing rectal intramural hematoma and perforation at the rectosigmoid junction. Because of the intestinal perforation, the patient was managed surgically. In the diagnosis of intramural hematoma of the alimentary tract, beside the clinical history and physical examination, the findings at imaging modalities such as conventional radiography, ultrasonography, and computed tomography are often useful. Patients with rectal intramural hematoma usually do not give diagnostic clues to the physicians in the clinical history. Therefore, radiologists must be familiar with the imaging findings. In this article, we aimed to present a patient with rectal intramural hematoma caused by foreign body and obliterating the rectal lumen.     

The histopathology of involutional ectropion and entropion

Objective: Involutional ectropion and entropion are characterized by excessive horizontal eyelid length, which is thought to be secondary to laxity of the medial and lateral canthal tendons and to the stretching of the tarsus. Histopathological features of the surgical eyelid specimens from patients with involutional ectropion and entropion were evaluated.Design: Prospective histopathological study.Participants: Eighteen full-thickness eyelid specimens from patients with involutional ectropion and entropion were obtained during horizontal eyelid shortening procedures performed at the Ministry of Health Ankara Training and Research Hospital.Methods: All specimens were fixed in 4% formaldehyde solution and sectioned sagittally. Hematoxylin-eosin, periodic acid-Schiff, and Masson's trichrome staining were done for all specimens. Histopathologic alterations of the tarsal plate, the palpebral portion of the orbicularis muscle, and the conjunctiva were examined.Results: The patients ranged in age from 60 to 80 years. The main histopathologic features of the ectropic eyelids included collagen degeneration and elastosis of the tarsal plate, increased amounts of adipose tissue in the distal tarsus, and subacute inflammation and epidermalization of the tarsal conjunctiva. Specimens from patients with involutional entropion generally had milder degrees of these histopathological features.Conclusions: The causes of the excessive horizontal length of the eyelid, which is thought to be secondary to laxity of the medial and lateral canthal tendons, may be collagen degeneration and elastosis of the tarsal plate and canthal tendons.     

Doctors' willingness to refer elderly patients for elective surgery

OBJECTIVES: We aimed to examine the relationship between doctors' willingness to refer elderly patients for elective surgical operations and patients' age, comorbidity, institutionalization, living habits and signs of dementia. METHOD: A random selection of 837 medical doctors in Finland (response rate 56%) received a postal questionnaire consisting of 18 vignettes, i.e. imaginary patient cases. Respondents were asked whether they would refer the patient on the vignette for elective surgical operation, treat the patient conservatively, or choose some other alternative. In the vignettes, the age of patients was randomly varied between 65 and 85, at 5-year intervals, to provide eight different questionnaires, and each respondent obtained one of them. RESULTS: The proportion of doctors willing to refer the patients for surgery was inversely related to the patients' age: in all the vignettes, doctors said they would refer fewer patients in the oldest age groups. Almost all the doctors claimed they would refer healthy, home-dwelling persons aged 65-70 years for operations. In the oldest age groups of patients, the doctors' willingness to refer was highest for cataract operations (69%) and hip prosthesis operations (63%), but only 18% of doctors would refer such patients for coronary by-pass operations. Comorbidity and institutionalization were associated with fewer doctors referring the patients: the proportion of doctors willing to refer these patients was about half that of those willing to refer otherwise healthy and home-dwelling patients. Smoking by patients also decreased the proportions of doctors willing to refer, but moderate signs of dementia in an elderly patient with cataract were associated with only a slight decrease in referring. CONCLUSIONS: Doctors are less willing to refer old patients for elective surgery, but comorbidity, patients' lifestyle and institutionalization have a greater effect on referrals than age.      

Anti-spasmogenic effects of bencianol (ZY15051) on human cerebral arteries in vitro

Experiments were performed to assess the ability of bencianol (ZY15051) to reverse contractions of human basilar arteries in vitro that were induced by a wide range of substances implicated in the aetiology of migraine and cerebral arterial spasm. Bencianol caused a dose-related (1-100 micrograms ml-1) reversal of contractions induced by 5-hydroxytryptamine, noradrenaline, angiotensin II, prostaglandin F2 alpha, and U-46619 (a thromboxane-A2 mimetic). Bencianol was more effective against contractions induced by EC50 compared to maximal concentrations of each agent, and was least effective against the thromboxane-A2 mimetic, U-46619. In addition, contractions induced by thromboxane-A2-like substances generated from guinea-pig lungs were also reversed by bencianol but only at the highest concentration used (100 micrograms ml-1). The relevance of this action of bencianol to migraine and cerebral arterial spasm is discussed.