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Biomedical subjects

J Zacharias

Publications and source records attributed to J Zacharias.

At least 19 recordsLinked to original sources
PubMed2004

Ten year experience of bioabsorbable mesh support in pectus excavatum repair.

INTRODUCTION: We reviewed 10 years experience in the treatment of this deformity using a retro-sternal bioabsorbable mesh in place of a metallic device to lift and stabilise the sternum. Moreover, the mesh supports the thoracic and upper abdominal wall reconstruction. MATERIALS AND METHODS: From January 1990 to December 2000, in our Thoracic Surgery Unit, 65 patients with PE were assessed for surgical repair, mean age 16+/- 3.5 years, fronto sagittal thoracic index (FSTI) 0.21, ranging from 0.15-0.33. Twenty-three of them underwent surgical correction after initial assessment, 22 were deferred and sent to physiotherapy. At a subsequent assessment, five of the patients sent to physiotherapy were deemed to require surgery. RESULTS: Of the 28 patients who underwent surgery, 2 (10%) presented a mild recurrence of PE after 1 year (0.30 0.34), meanwhile all other patients maintained a FSTI>0.34. For all patients the improvement in FSTI was statistically significant, p = 0.001. Patients satisfaction after 24 months was thus shared: excellent 18 patients (65%), good seven patients (25%), fair one patient (3.5%) and poor two patients (7%). No major complications were observed in preoperative period. Patients mobilisation was soon achieved thanks to the postoperative pain control and the absence of retro-sternal metallic support. CONCLUSIONS: The introduction of bioabsorbable mesh in the Robicsek technique is a safe procedure related to a high percentage of success. The high tolerance of the material reduces the inflammatory reaction. Moreover, the procedure prevents patients from having complications caused by retro-sternal device dislodgment, avoiding a second intervention for device reposition and reducing the postoperative chest pain achieving an early patient mobilisation. In the end a complete reconstruction of the upper abdomen wall has been produced.

Absorbable Implants↗
PubMed2000

Effect of low molecular weight heparin (fragmin) on bleeding after cardiac surgery.

BACKGROUND: Fragmin (Dalteparin, Pharmacia Ltd, Milton Keynes, UK), a low molecular weight heparin, is now recommended in the treatment of unstable angina. Due to the greater bioavailability and longer half-life of Fragmin compared with conventional heparin we postulated that this may influence postoperative bleeding after cardiac surgery for unstable angina. METHODS: We investigated the influence of the agent on postoperative bleeding after cardiac surgery. Patients undergoing first-time coronary artery bypass grafting were prospectively studied in four groups: group A (n = 100) were elective patients; group B (n = 60) had unstable angina and received conventional heparin intravenously until operation; group C (n = 115) received Fragmin with the last dose administered more than 12 hours before surgery; and group D (n = 115) received Fragmin within 12 hours of operation. RESULTS: Patients in group D had significantly greater blood loss (p < 0.001) and increased blood transfusion than groups A, B, and C (p = 0.047). Patients receiving Fragmin more than 12 hours before surgery (group C) had similar rates of blood loss and transfusion to group B (p > 0.05) but greater than in group A (p = 0.021). There were no differences in reopening rate. CONCLUSIONS: The risks of bleeding and transfusion must be weighed against the risks of acute ischemic events if Fragmin is stopped more than 12 hours before operation.

Aged↗
PubMed2000

Early postoperative capsular block syndrome related to saccadic-eye-movement-induced fluid flow into the capsular bag.

PURPOSE: To determine the relationship between saccadic eye movements and the development of early postoperative capsular block syndrome. SETTING: Fundacion Oftalmologica, Los Andes, Santiago, Chile. METHODS: An artificial experimental setup was designed to reproduce the anatomical, hydrodynamic, and kinetic conditions of an early postoperative pseudophakic eye with a capsulorhexis and intracapsular intraocular lens (IOL) implantation. An electromechanical transducer driven by a digital-to-analog converter was used to mimic saccadic eye movements at physiological speeds and accelerations. Position information and differential pressure measurements between the intracapsular space and the extracapsular space were digitized. Various anterior capsule-IOL configurations were tested including partial adhesion of the anterior capsule to the lens. RESULTS: Saccadic movements increased intracapsular pressure by displacing fluid into the capsular bag. This finding was inconstant and only observed when the capsular rim adhered to the IOL optic by more than 70%. Development of positive intracapsular pressure was noted above 4 mm Hg. CONCLUSION: A valve-like mechanism formed by the capsulorhexis rim partially adhered to the IOL optic can occur postoperatively. Under these conditions, saccadic eye movements can increase intracapsular pressure by a unidirectional inertial displacement of fluid into the capsular bag.

Aqueous Humor↗
PubMed1998

Effect of pergolide on restless legs and leg movements in sleep in uremic patients.

Restless legs syndrome (RLS) and periodic limb movements in sleep (PLMS) are disorders that are common and disturbing to uremic patients. The treatment of these is problematic. Eight patients on chronic hemodialysis and continuous peritoneal dialysis completed a double-blind placebo-controlled crossover study using incremental doses of pergolide up to 0.25 mg at bedtime for treatment of RLS and sleep disruption. Five patients (62.5%) noted subjective improvement in restless legs symptoms and sleep quality. Objective results were improved only slightly by treatment. The percentage of the first hour in bed during which leg movements occurred decreased from 20.5 +/- 6.0 to 11.5 +/- 3.3, p < 0.05. However, findings during sleep were less positive. The following measures were not significant between placebo and treatment: leg movements per hour of sleep [53.7 +/- 22.3 vs 35.8 +/- 11.8 (p = 0.2)]; and percentage of sleep time spent with leg movements [5.5% +/- 3.2 vs 4.4% +/- 1.4 (p = 0.37)]. Patients continued to have very disrupted sleep, and we could not document an objective improvement in sleep architecture. Thus, although pergolide at the dose of 0.25 mg at bedtime provided subjective improvement in symptoms of restless legs and quality of sleep, and objectively decreased leg movements during the first hour in bed, objectively sleep continued to be disrupted. In this small patient group, the response to pergolide was not uniform, and further investigation is required to test effectiveness at higher doses.

Adult↗
PubMed1998

Results of preprocedure and postprocedure toe cultures in orthopaedic surgery.

This study was to determine whether there is any benefit to wrapping the toes sterilely during orthopaedic procedures not involving the foot but performed on the lower extremity. The group studied consisted of 12 patients who had an orthopaedic procedure performed in which the foot and toes were included in the surgical prep, but not involved in the surgical procedure. Nine of the 12 patients (75%) had positive results from preprocedural aerobic cultures and two of the 12 (16.6%) had positive results from preprocedural fungal cultures. Recolonization of the bacteria between the toes was also demonstrated. Sterile draping of the toes would minimize the risk of infection and also protect against bacteria that recolonize during the procedure.

Adolescent↗
PubMed1995

Acetabular fractures.

Acetabular fractures are not uncommon injuries of the pelvis. They are most frequently associated with high energy trauma such as that seen in a motor vehicle accident. Management of patients with acetabular fractures includes careful attention to ATLS (advanced Trauma Life Support) protocols and delayed operative treatment of the acetabular fractures. Diagnostic evaluation with plain radiography and CT is used to plan the treatment approach. Treatment includes not only the recognition of the fracture but avoidance of early and late complications. Emergent treatment includes closed reduction of associated hip dislocations followed by skeletal traction. Delayed reconstruction at four days after the injury decreases intraoperative blood loss by allowing retroperitoneal hemorrhage to subside. Final outcome after acetabular trauma depends not only on the reconstruction of the fracture, but the avoidance of complications. Acetabular fractures are becoming an increasingly common orthopedic injury. Fractures of the acetabulum (or hip socket) are most commonly seen after motor vehicle accidents. Young patients (18 to 30 years old) are typically affected. A frequent mechanism of injury is a direct blow to the anterior aspect of the knee with the hip flexed such as a dashboard injury in an automobile accident. Other mechanisms of injury include direct blows to the lateral aspect of the hip as in a fall from a height or a side impact automobile collision.

Accidents, Traffic↗
PubMed1987

Gallbladder wall thickening: a frequent finding in various nonbiliary disorders--a prospective ultrasonographic study.

A comprehensive prospective ultrasonographic study was performed in 93 patients to investigate gallbladder wall thickness and gallbladder volumes in various nonbiliary disease states. Without changes in gallbladder volume, mean gallbladder wall thickness was significantly increased (p less than 0.01) in patients with liver cirrhosis, viral hepatitis, chronic congestive heart failure, hypoalbuminemia, and chronic renal failure (p less than 0.05) but not in patients with diabetes mellitus (n = 14) as compared to a control group. The present study confirms that a variety of nonbiliary disorders are associated with significant thickening of gallbladder walls and that this finding is not caused by incomplete gallbladder contraction.

Diabetes Mellitus↗
PubMed1985

Effects of cholinergic drugs and 4-aminopyridine on cat ciliary muscle contractility.

The effects of some cholinergic agents and 4-aminopyridine (4-AP) on neurally mediated contractions of in vitro cat ciliary muscle preparations were studied. The contractile response to trains of stimuli was enhanced by eserine and completely blocked by tetrodotoxin or atropine. Low concentrations of carbachol did not modify muscle resting tension but clearly attenuated contractile response to electrical stimuli, while higher concentrations increased the resting tonus leading to contracture which did not respond to further stimulation. 4-AP is known to be a potassium-channel blocking drug that increases neurotransmitter release at nerve terminals during the action potential. This substance exhibited a dose-related potentiation of the evoked ciliary muscle contractions without changing resting tension. The eventual reducing effect of 4-AP on the accommodative convergence/accommodation ratio (AC/A) is discussed in relation to its potential clinical application in certain strabismus patients.

4-Aminopyridine↗
PubMed1984

Electrophysiological effects of 4-aminoquinoline on frog atrial contractile fibres.

The effects of 4-aminoquinoline (4-AQ), a drug structurally related to 4-aminopyridine, were studied on atrial contractile fibres from the amphibian Caudiverbera caudiverbera by means of intracellular electrodes. In concentrations that did not change resting potential, 4-AQ (0.25-1.5 mM) reduced upstroke velocity, action potential amplitude (APA) and overshoot in a dose-dependent manner. 4-AQ also prolonged action potential duration (APD) and the fibre effective refractory period (ERP), making the ratio ERP/APD greater than one. These effects were reversible by washing. The drug-induced reduction of upstroke velocity was frequency-dependent. This effect and increase of APD were more intense at higher values of resting potential. All effects produced by 4-AQ remained constant in either high or low external K+ concentrations. The depressant effects of this compound on upstroke velocity, overshoot, APA as well as increase of APD were antagonized by doubling the extracellular Na+ concentration. Data presented support the view that 4-AQ exerts its effects on the frog heart by blocking both sodium and potassium channels, thus causing quinidine-like actions.

Action Potentials↗
PubMed1980

Acceptance of amniocentesis by low-income patients in an urban hospital.

A study was made of increased accessibility of genetic services to low-income obstetric patients in Atlanta, Georgia. The proportion of black patients averaged 83%. Of 522 patients counseled from August, 1976, through 1978, 157 were offered amniocentesis, and 95 (61%) elected the procedure. For most of the patients (120, or 76%) who were eligible for amniocentesis, age (greater than or equal to 35 years at delivery) was an indication; and of these, only six (5%) had any prior knowledge of genetic risk. During the same time interval, 188 patients over 35 years of age who initiated prenatal care too late for prenatal diagnosis were counseled in the hospital after delivery; 101 (54%) indicated that they would have accepted amniocentesis. The conclusion was that (1) genetic services are acceptable to this socioeconomic group, and (2) accessibility and publicity are needed to promote utilization in this population.

Amniocentesis↗