Evidence for McKusick''s hypothesis of deficient collagen cross-linking in patients with homocystinuria

Fractionation of the venom of the spider Phoneutria nigriventer revealed that it was a mixture of several neurotoxic peptides. The peptides so far characterized either inhibited or induced neurotransmitter release. These effects were mediated by Ca2+ channels or increasing Na+ permeability through voltage sensitive Na(+)-channels, respectively. The pooled toxic components (fraction P4) showed stimulatory effects on acetylcholine release from brain cortical slices. In addition, a component of the observed effects resembling that of alpha-latrotoxin was identified, which was characterized by the ability to provoke release of acetylcholine (ACh) at low temperature and in a manner independent of extracellular Ca2+ and of voltage sensitive Na(+)-channels.     

The next challenge for newborn intensive care in Alaska: improving the survival of the larger neonate

Using information from our database, a review of mortality for the Newborn Intensive Care Unit at Providence Alaska Medical Center was conducted for 1987-1996. There has been a significant decline in mortality over the last decade (p = 0.003). An analysis of mortality by birthweight and gestational age groups demonstrated a decline in mortality (p = 0.005) for infants with birthweight < 2 kg and infants < or = 34 weeks gestation, but no change for infants > or = 2 kg and > or = 35 weeks gestation. As a result, larger and more mature babies now account for an increasing proportion of NICU deaths. For 1995 and 1996 the major contributors to mortality for the smaller neonates were respiratory distress syndrome and congenital and nosocomial sepsis/pneumonia. The major contributors to mortality for larger neonates were persistent pulmonary hypertension of the newborn, congenital heart disease, congenital diaphragmatic hernia, and primary birth asphyxia. A majority of deaths in the larger neonates were due to non-lethal causes. We contend that improved survival in the larger neonate is an important and achievable goal. The introduction of ECMO (Extracorporeal Membrane Oxygenation) for the NICU and a focused review of the neonatal cardiac program offers the best possible potential for achieving this goal.     

Continuous liquid-phase piezoelectric biosensor for kinetic immunoassays

The reactions of immunoglobulins with protein A and, subsequently, of antibodies to these immunoglobulins were continuously monitored by a piezoelectric biosensor. AT-cut crystals, with a fundamental resonant frequency of 10 MHz, were mounted in a Plexiglas holder, and one side was directly coated with protein A. Upon exposure to solutions containing rabbit or human IgG the resonant frequency was followed continuously and its decrease due to the binding of IgG to protein A observed. Subsequent addition of sheep antihuman IgG to the now immobilized human IgG caused a specific 3-fold further decrease in resonant frequency. We observed a frequency change of approximately 1 Hz fore each 10 ng of added immunoglobulin. Decreasing the pH to 3 released the bound IgG but not the protein A and permitted reuse of the crystal for further IgG binding.     

Optical sequence generation based on collision avoidance usingchaotic mode transitions

An adaptive optical sequence generation scheme has been described in a nonlinear optical ring which exhibits chaotic dynamics. The adaptation is based on avoidance of collisions between the ring output and signals from another source. It is shown that collision-avoiding sequences can be autonomously selected via chaotic mode transitions induced by the feedback of collision signals. Experimental results demonstrate that the method can be successful for various collision signal patterns with different periods and pulsewidths. The mechanism of inducing chaos with collision signals is examined both experimentally and with numerical simulations and the results verify the effectiveness of the proposed adaptation method. A possible application of the proposed signal generation scheme in intelligent optical communication networks is mentioned     

Implanted functional electrical stimulation hand system in adolescents with spinal injuries: an evaluation

OBJECTIVE: To study the utility and functional benefits of an implanted functional electrical stimulation (FES) system for hand grasp and release in adolescents with tetraplegia secondary to spinal cord injuries. DESIGN: Intervention study with before-after trial measurement with each subject as his or her own control. SETTING: Nonprofit pediatric orthopedic rehabilitation facility specializing in spinal cord injury. PARTICIPANTS: A convenience sample of five adolescents between 16 and 18 years of age with C5 or C6 level tetraplegia at least 1 year after traumatic spinal cord injury. Key muscles for palmar and lateral grasp and release were excitable by electrical stimulation. INTERVENTIONS: A multichannel stimulator/receiver and eight electrodes were surgically implanted to provide stimulated palmar and lateral grasp and release. In conjunction with implantation of the FES hand system, surgical reconstruction in the form of tendon transfers, tendon lengthenings and releases, and joint arthrodeses was performed to augment stimulated hand function. Rehabilitation of the tendon transfers and training in the use of the FES hand system were provided. MAIN OUTCOME MEASURES: Measurements of pinch and grasp force, the Grasp and Release Test (GRT), and an assessment of six activities of daily living (ADL) were administered before implantation of the FES hand system and at regular follow-up intervals. Results of the stimulated response of individual muscles and surgical reconstruction were evaluated using standard and stimulated muscle testing techniques and standard assessment of joint range of motion. All subjects completed followup testing. RESULTS: Lateral and palmar forces were significantly greater than baseline forces (p = .043). Heavy objects on the GRT could only be manipulated with FES, and FES increased the level of independence in 25 of 30 ADL comparisons (5 subjects, 6 activities) as compared to baseline. After training, FES was preferred in 21 of 30 comparisons over the typical means of task completion. Of the 40 electrodes implanted, 37 continue to provide excellent stimulated responses and all of the implanted stimulators have functioned without problems. The surgical reconstruction procedures greatly enhanced FES hand function by either expanding the workspace in which to utilize FES (deltoid to triceps transfer), stabilizing the wrist (brachioradialis to wrist extensor transfer), or stabilizing joints (intrinsic tenodesis transfer, FPL split transfer). CONCLUSION: For five adolescents with tetraplegia, the combination of FES and surgical reconstruction provided active palmar and lateral grasp and release. Laboratory-based assessments demonstrated that the FES system increased pinch force, improved the manipulation of objects, and typically increased independence in six standard ADL as compared to pre-FES hand function. The study also showed that the five adolescents generally preferred FES for most of the ADL tested. Data on the benefits of the implanted FES hand system outside of the laboratory are needed to understand the full potential of FES.     

Background-subtraction using contour-based fusion of thermal and visible imagery

We present a new background-subtraction technique fusing contours from thermal and visible imagery for persistent object detection in urban settings. Statistical background-subtraction in the thermal domain is used to identify the initial regions-of-interest. Color and intensity information are used within these areas to obtain the corresponding regions-of-interest in the visible domain. Within each region, input and background gradient information are combined to form a Contour Saliency Map. The binary contour fragments, obtained from corresponding Contour Saliency Maps, are then fused into a single image. An A^* path-constrained search along watershed boundaries of the regions-of-interest is used to complete and close any broken segments in the fused contour image. Lastly, the contour image is flood-filled to produce silhouettes. Results of our approach are evaluated quantitatively and compared with other low- and high-level fusion techniques using manually segmented data.     

Association of herpes zoster ophthalmicus with acquired immunodeficiency syndrome and acute retinal necrosis

We conducted a review to investigate the prevalence of human immunodeficiency virus (HIV), or acquired immunodeficiency syndrome (AIDS), in patients with herpes zoster ophthalmicus, as well as the incidence of acute retinal necrosis after herpes zoster ophthalmicus. All charts of patients seen at our institution between 1987 and 1992 with a primary diagnosis of herpes zoster ophthalmicus were reviewed. Of 112 patients with herpes zoster ophthalmicus, 29 (26%) had HIV or AIDS. All these patients were younger than 50 years at the time of diagnosis. Five of 29 (17%) immunocompromised patients had acute retinal necrosis after herpes zoster ophthalmicus. No acute retinal necrosis was identified in the nonimmunocompromised patients after herpes zoster ophthalmicus. We recommend that all patients younger than 50 years who have herpes zoster ophthalmicus at initial examination be tested for HIV. Additionally, HIV-infected patients should be monitored closely after herpes zoster ophthalmicus for development of acute retinal necrosis. Long-term oral prophylactic as well as initial high-dose intravenous acyclovir may be appropriate in HIV-infected individuals with herpes zoster.