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Micron-size particles emission from bioceramics induced by pulsed laser deposition.

Pulsed laser deposition of hydroxyapatite is applied to cover titanium medical prosthesis. Laser irradiation of ceramics by power-pulsed ruby laser produces high velocity micron-size particles emission with a narrow ejection plume directed normally to the target surface. Photoemitted particles are deposited on a metal surface at 400 degrees C to obtain a granular film, stoichiometric, polycrystalline, and very adherent to the substrate. Deposited films are highly biocompatible and may be used to induce osteointegration processes of the implanted prosthesis with the bone tissues. The comparison between laser and plasma spray depositions of bioceramics is discussed.

Ceramics↗

Localized permanent epidemics: the genesis of chloroquine resistance in Plasmodium falciparum.

Localized permanent epidemics occur when, for an indefinite period of time, there is a temporary but continuous introduction of unprotected non-immunes into the same locality of a hyperendemic area. The main epidemiological factors involved in the genesis of localized permanent epidemics were encountered in Pailin (Cambodia) the epicenter of drug resistance in Southeast Asia: a very efficient vector, Anopheles dirus, exophilic and of limited distribution with, therefore, adjacent hyperendemic and non-endemic areas; a permanent pole of attraction in the hyperendemic area: Pailin's sapphires and rubies; a temporary but continuous influx of non-immunes into the pole of attraction: continuous influx of non-immunes into the Pailin gem mining area. In the gem-mining Pailin village drug pressure was considerable: mass drug administration, a medicated salt project and permanent self-medication with very high doses, much higher doses being required to cure non-immunes with heavy infections and severe clinical attacks in epidemic situations. It appears, therefore, that the emergence of chloroquine resistance in Southeast Asia was the consequence of the localized permanent epidemics in Païlin. High level resistance was the result of continuous and intensive serial passages of P. falciparum in the non-immune subjects, large numbers of parasites being exposed to a high level of drug pressure at each passage. Similar epidemiological conditions are encountered in some parts of South America where the exophilic vector is An. nuneztovari. In Colombia, whose eastern mountains bordering Venezuela yield the most highly prized emeralds in the world, chloroquine resistance was detected at about the same time as in Southeast Asia.(ABSTRACT TRUNCATED AT 250 WORDS)

Africa↗

[Treatment of diabetic retinopathy. Clinical experience with various lasers. Complications associated with lasers].

Since the ruby laser was first introduced in the early sixties, different types of lasers and different wavelengths have been used to treat diabetic retinopathy. Although longer wavelengths may be preferable in selected cases, different studies were unable to demonstrate significantly different results when diabetic retinopathy or maculopathy was treated with different wavelengths. The quality of the treatment as well as the incidence of complications depend on the technique used and the experience of the treating ophthalmologist. Some complications such as pain during treatment or vitreous haemorrhage can not always be avoided. Other complications such as a foveal burn are unacceptable. It is also possible by using an appropriate technique to minimize visual field restriction.

Diabetic Retinopathy↗

A visual guidance program: evaluation report.

A group of 80 fourth-grade pupils were administered visual tests to identify poor eye synchronization. The tests were given at Ruby Thomas Elementary School, Las Vegas, Nevada during February 1971 by Drs. Fred Erlich and Harvey Ohriner. Pupils with unsatisfactory eye synchronization were divided into two groups, a treatment and non-treatment or control group. A second control group was randomly selected from pupils with satisfactory eye synchronization. Visual guidance exercises were given to the treatment group. Post test reading tests showed significant gains in reading for the treatment group. Control groups showed non-significant gains.

Child↗

Injuries related to logging: epidemiology, etiology and implications for prevention.

This article describes our study of 36 male patients who were brought to Ruby Memorial Hospital in Morgantown for treatment of non-fatal logging-related injuries. The type and severity of their injuries is described, as well as the host, vehicular/mechanical and environmental factors contributing to the injuries. The suggestions of the patients on how to prevent their injuries are compared to existing OSHA standards.

Accidents, Occupational↗

Input-output connections of the "hindlimb" region of the inferior olive in cats.

The aim of the present study was to establish whether gracile afferents to the inferior olive are topographically organized and whether such inputs coincide with the location of cells that output to the hindlimb C1 zone in the cerebellar posterior lobe. Small injections (n=15) of the anterograde tracers Fluoro-Ruby or biotinylated dextran amine were made into gracile, resulting in anterograde labelling often distributed in partially separate, rostrocaudally directed columns within the lateral half of the contralateral rostral dorsal accessory olive (rDAO). In 12 cases, anterograde labelling was also located within the caudolateral medial accessory olive. Evidence for a topographical organization was obtained, suggesting that medial gracile targets only the most lateral part of rDAO, whereas lateral gracile also targets more medial parts. Gracile injections centred dorsally also resulted in more extensive terminal fields in rDAO than similar sized injections centred ventrally which may relate to the representation of the distal hindlimb in dorsal gracile (e.g., Millar and Basbaum, 1975). Injections of retrograde tracer (green beads) into the C1 zone in the ipsilateral caudal paramedian lobule (7 cases), resulted in retrograde cell labelling in the middle one-third of contralateral DAO in two columns that fused caudally. The proportion of labelled cells that overlapped with anterograde labelled terminals was related to the dorsoventral locus of the gracile injection site: gracile injections centred dorsally produced the largest degree of overlap and therefore, potentially, the greatest functional convergence. In summary, the results suggest that a topographical organization is present within the gracilo-olivo-cerebellar projection which is discussed in relation to the functional organization of the olivocerebellar system.

Animals↗

Blood buffy coat from Alzheimer's disease patients and their relatives does not transmit spongiform encephalopathy to hamsters.

There was a report of spongiform encephalopathy transmitted to Syrian hamsters by intracerebral inoculation with the blood buffy coat of patients with Alzheimer's disease (AD) and their unaffected first-degree relatives. We attempted to verify that report, taking measures to reduce the risk of contaminating samples with agents causing spongiform encephalopathies. We obtained blood from 50 subjects, including six patients with familial AD, 21 unaffected first-degree relatives (siblings and offspring) of patients with familial AD, and 20 control subjects. We inoculated the buffy coats intracerebrally into Syrian LVG hamsters, observed them for signs of neurologic disease, examined their brains for neuropathologic changes at time of death, and performed serial (blind) passages by inoculating suspensions of all recovered brains into fresh LVG hamsters. We discerned no clinical illness or histopathologic changes resembling experimental spongiform encephalopathy in any hamster inoculated with human buffy coat nor in blind-passage hamsters, nor were the life spans of those hamsters shortened. We conclude that AD is not caused by an agent that transmits spongiform encephalopathy to hamsters.

Alzheimer Disease↗

Asymptomatic bacteriuria in women with diabetes mellitus: effect on renal function after 6 years of follow-up.

BACKGROUND: The long-term consequences of asymptomatic bacteriuria (ASB) on renal function in women with diabetes mellitus (DM) are unknown. METHODS: A prospective study was performed among women with type 1 or type 2 DM. Women with ASB (diagnosis based on findings from 1 urine culture specimen) were compared with women without ASB for differences in renal function development and incidence of hypertension. RESULTS: A total of 644 women were included in the study (296 with type 1 DM and 348 with type 2 DM; mean [SD] age, 51 [15] years) and followed up for a mean (SD) duration of 6.1 (1.9) years. The prevalence of ASB was 17%. In women with DM and ASB, the creatinine clearance decreased from 87 mL/min (1.45 mL/s) at baseline to 76 mL/min (1.27 mL/s) at study end point; in women with DM without ASB the creatinine clearance decreased from 97 to 88 mL/min (from 1.62 to 1.47 mL/s). In the multivariate analyses, adjusted for age, length of follow-up, duration of DM, and microalbuminuria at baseline, no association was found between ASB and the relative or the absolute decrease in creatinine clearance; the same results were shown also when women with DM type 1 and women with DM type 2 were analyzed separately. Women with ASB developed hypertension more often than women without ASB (54% vs 37%; P = .045), but there was no significant association in the multivariate analysis (odds ratio, 1.5; 95% confidence interval, 0.7-3.6). CONCLUSION: Women with DM (type 1 or type 2) with ASB do not have an increased risk for a faster decline in renal function or the development of hypertension after 6 years of follow-up.

Adolescent↗

Choroidal neovascularization associated with choroidal hemangiomas.

Two patients with choroidal hemangiomas developed choroidal neovascularization. One patient with Sturge-Weber syndrome, a unilateral diffuse choroidal hemangioma, and a serous detachment of the macula was treated with yellow dye laser photocoagulation in a grid pattern to the tumor before glaucoma filtration surgery. Four years after successful laser treatment, the patient developed subfoveal choroidal neovascularization in an area of treatment. A second patient with a circumscribed choroidal hemangioma developed spontaneous subfoveal choroidal neovascularization 12 years after initial diagnosis of the hemangioma. The development of choroidal neovascularization associated with choroidal hemangiomas represents a potential cause of poor visual outcome in these patients.

Adolescent↗

Pars plana vitrectomy for treatment of stage 2 macular holes.

OBJECTIVE: To assess the anatomic outcome and visual acuities at follow-up after pars plana vitrectomy in the management of stage 2 macular holes. DESIGN: Retrospective. SETTING: Retina Consultants, Ltd, St Louis, Mo. PATIENTS: Thirty-three patients, aged 43 to 75 years, with stage 2 macular holes. INTERVENTION: Total pars plana vitrectomy with separation of the posterior hyaloid membrane and injection of intraocular gas followed by postoperative face-down positioning. MAIN OUTCOME MEASURES: Visual acuity and anatomic appearance of the macular hole. RESULTS: Postoperatively, 20 (61%) of 33 eyes attained a visual acuity of 20/50 or greater. Twenty (61%) of 33 eyes showed an improvement in visual acuity, while nine (27%) of 33 were stable. Four (12%) of 33 eyes showed a decline in postoperative visual acuity with progression to a stage 3 macular hole. Twenty-five (76%) of 33 eyes showed stabilization or improvement in the appearance of the macular hole. CONCLUSIONS: Pars plana vitrectomy in conjunction with postoperative intraocular gas tamponade may result in visual and anatomic stabilization or improvement in eyes with stage 2 macular holes. However, because of limited natural history data, it is unknown whether these results are any better than those that might occur without surgery.

Adult↗

Surgical management of submacular hemorrhage. A series of 47 consecutive cases.

BACKGROUND: The development of a thick submacular hemorrhage usually carries a poor visual prognosis. The surgical removal of submacular blood may improve the otherwise poor outlook in these cases. SUBJECTS AND METHODS: Forty-seven consecutive patients underwent vitrectomy with surgical removal of submacular hemorrhage. The patient population consisted of two consecutive groups. Group 1 (1989 to 1991) included 23 patients (20 with age-related macular degeneration [ARMD], one with idiopathic submacular hemorrhage, one with presumed ocular histoplasmosis syndrome [POHS], and one with angioid streaks) who underwent mechanical clot extraction. Group 2 (1991 to 1993) included 24 patients (19 with ARMD, two with POHS, two with arterial macroaneurysm, and one with angioid streaks) who underwent tissue plasminogen activator-assisted drainage of thick submacular hemorrhage. The dose of tissue plasminogen activator ranged from 10 to 40 micrograms. All patients had surgery within 72 hours of diagnosis. RESULTS: In group 1, the mean size of the submacular hemorrhage was 11 disc areas (range, 1 to 16 disc areas). Mean follow-up was 40 weeks. Mean postoperative visual acuity for eyes with ARMD was 20/200. (Visual acuity improved in six eyes, was stable in seven eyes, and deteriorated in seven eyes.) All three of the eyes without ARMD had visual improvement with a mean postoperative visual acuity of 20/70. Overall, visual acuity stabilized or improved in 13 (57%) of 23 patients and decreased in 10 (43%) patients. In group 2, the mean size of the submacular hemorrhage was 11 disc areas (range, 3 to 16 disc areas). Mean follow-up was 24 weeks. Mean postoperative visual acuity for eyes with ARMD was 20/480 (visual acuity was stable in 15 eyes, improved in two eyes, and deteriorated in two eyes). Four of five eyes without ARMD had visual improvement and one was stable, with a mean postoperative visual acuity of 20/60. Visual acuity stabilized or improved in 22 (92%) of 24 patients and decreased in two (8%). The degree of clot lysis was variable. CONCLUSIONS: Submacular hemorrhage secondary to ARMD has a poor visual prognosis, with or without surgical drainage. The addition of tissue plasminogen activator-assisted clot lysis does not appear to significantly improve the visual outcome following surgery. The determination of whether surgical intervention is appropriate in these cases requires a prospective, randomized clinical trial.

Aged↗

Association of promoter variants in the alpha7 nicotinic acetylcholine receptor subunit gene with an inhibitory deficit found in schizophrenia.

BACKGROUND: The alpha7 neuronal nicotinic acetylcholine receptor subunit gene (CHRNA7) has been implicated as a candidate gene for schizophrenia, and for an auditory sensory processing deficit found in the disease, by both genetic linkage at 15q14 and biochemical data. The expression of CHRNA7 is reduced in several brain regions in schizophrenic subjects compared with control subjects. This study presents DNA sequence analysis of the core promoter region for CHRNA7 in schizophrenic and control subjects. METHODS: Single-strand conformation polymorphism analysis and DNA sequencing were used for mutation screening of the core promoter in the CHRNA7 gene. The sample included subjects from 166 schizophrenic families and 165 controls. Controls had no evidence of current or past psychosis and had auditory evoked potentials recorded. RESULTS: Multiple polymorphic patterns were identified in the CHRNA7 core promoter in both schizophrenic and control subjects. Functional analysis of polymorphisms indicated that transcription was reduced. The prevalence of functional promoter variants was statistically greater in schizophrenic subjects than in the controls. Presence of an alpha7 promoter polymorphism in controls was associated with failure to inhibit the P50 auditory evoked potential response. CONCLUSIONS: Although linkage disequilibrium with other genetic alterations cannot be excluded, the CHRNA7 core promoter variants, found in this study, may contribute to a common pathophysiologic feature of schizophrenia.

Auditory Perceptual Disorders↗

Palliation of tricuspid atresia. Potts-Smith, Glenn, and Blalock-Taussig shunts.

Aortopulmonary (Potts-Smith), subclavian-pulmonary (Blalock-Taussig), and cavopulmonary (Glenn) shunts are the commonly performed operations for palliation of tricuspid atresia. A total of 104 patients with tricuspid atresia have undergone these procedures, either alone or in combination over a 28-year-period at the Hospital for Sick Children, Toronto. Operative risk is high in the first six months of life (44%), reasonable after six months of age (7.4%), and low for reoperation (3.5%). Long-term palliation of the 75 survivors (mean follow-up, 8,5 years) is compared for the three operative groups and charted on an actuarial table. Potts shunt offers superior long-term palliation. Therefore, as an overall plan of management, a Potts shunt with restriction of its anastomotic growth is the initial procedure of choice. When the patient outgrows the Potts shunt, a Glenn anastomosis is constructed. Ideally, the combination of these two shunts will produce a balanced circulation offering excellent long-term palliation.

Adolescent↗

Release of chemotactic factors by veins during preparation for arterial bypass.

With the use of arterial bypass release neutrophil chemotactic factors, saphenous veins were removed from dogs by means of standard surgical technique and were distended to a pressure of 200 mm Hg for 15 minutes with cold (4 degrees C) plasmalyte solution. Veins cannulated in situ and flushed with cold (4 degrees C) plasmalyte solution served as negative controls. Experimental and control flush solutions were assayed for the presence of neutrophil chemotactic factors with the use of modified Boyden chambers. Chemotactic activity from the distended vein grafts was 2.2 to 7.2 times the control value. Biologic chemotactic activity was demonstrated as well. These results suggest a role for the vein graft itself in the recruitment of neutrophils to implanted veins by releasing chemoattractants.

Animals↗

Survey of residents' attitudes toward reform of work hours.

Traditional work schedules of surgical residents have been cited as a factor that negatively influences residency education and the quality of patient care. As an adjunct to the formulation of recommendations for the development of the environment for general surgery training, the New England Association of Program Directors in Surgery set out to sample the attitudes of surgical residents in New England relative to their perceived need to reform work hours. Seventy-two percent of the residents thought there was a need for some level of resident work schedule change. The major variable that correlated with this opinion was the reported amount of sleep that a resident needed before returning to work after a 24-hour shift. The ultimate effect on education, patient care, and fiscal resources of these potentially sensitive changes remains to be determined.

Adult↗

Preliminary assessment of a scientific curriculum in a surgical residency program.

A structured, basic science curriculum was instituted for surgical residents of the University of Connecticut (Farmington) Integrated Residency Program during the 1990-1991 academic year in concordance with American Board of Surgery guidelines. The impact of the new program was measured by comparing performance on monthly basic science examinations, the in-training examination, and "mock" oral examinations for the 1990-1991 academic year with that of the preceding academic year. While monthly examination scores improved for the entire group of residents (67.7 vs 64.6), in-training and oral examination scores did not change significantly. Categorical residents generally demonstrated superior performance and greater improvement than did preliminary residents. Data analysis suggested that the new curriculum was an effective educational device and that university-designed monthly examinations were valid testing instruments, but there was an apparent incongruity between the goals of the curriculum and the American Board of Surgery In-Training Examination.

Attitude↗