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Biomedical subjects

M A Friedberg

Publications and source records attributed to M A Friedberg.

17 recordsLinked to original sources
PubMed2001

Globe perforation associated with subtenon's anesthesia.

PURPOSE: To report a case of globe perforation while initiating posterior subtenon's anesthesia. METHODS: Case report. A 40-year-old man with a history of retinal detachment in both eyes presented for repair of a second retinal detachment in the LE. RESULTS: Upon dissecting a space beneath the Tenon capsule with scissors, the globe was perforated. CONCLUSION: In patients with prior ophthalmologic surgery, thinned sclera, or excess scar tissue, increased caution should be employed during initiation of sub-Tenon anesthesia or an alternative method should be used.

Adult↗
PubMed1998

Effect of flow rate and insulin priming on the recovery of insulin from microbore infusion tubing.

BACKGROUND: A retrospective medical record review of 13 consecutive, hyperglycemic, extremely low birth weight (ELBW) infants treated with continuous insulin infusions revealed a 14- to 24-hour delay (mean, 19 hours) in blood glucose normalization despite stepwise increases in insulin infusion rates. OBJECTIVE: This in vitro study examined the effects of flow rate and insulin priming on insulin recovery from polyvinyl chloride (PVC) tubing and polyethylene (PE)-lined PVC tubing infused with a standard insulin stock solution. METHODS: Stock insulin solution (0.2 U/mL) was infused through microbore PVC or PE-lined tubing at flow rates of 0.05 and 0.2 mL/h. To determine if saturation of nonspecific binding sites would alter effluent insulin concentration, we compared insulin recovery from tubing previously flushed with the stock solution and tubing primed with 5 U/mL of insulin for 20 minutes. Effluent samples, which were collected at baseline and at six time points during a 24-hour period, were immediately frozen at -20 degreesC. Insulin concentration was measured by IMx immunoassay. Data were analyzed using general linear modeling with repeated measures. RESULTS: At 0.05 mL/h flow rate, insulin recovery from unprimed PVC tubing at 1, 2, 4, and 8 hours was 17%, 11%, 27%, and 55%, respectively, with 100% recovery at 24 hours. From insulin-primed tubing, insulin recovery was approximately 70% at 1, 2, and 4 hours, and close to 100% at 8 hours. At a faster flow rate of 0.2 mL/h, insulin recovery at 1, 2, 4, and 8 hours was 22%, 38%, 67%, and 75% vs 42%, 85%, 91% and 95% from unprimed and insulin-primed PVC tubing, respectively. Similar results were obtained from unprimed and insulin-primed PE-lined tubing at 0.2 mL/h flow rate. CONCLUSIONS: Priming of microbore tubing with 5 U/mL of insulin solution for 20 minutes to block nonspecific binding sites enhances delivery of a standard insulin stock at infusion rates typically used to treat hyperglycemic ELBW infants. We conclude that priming the tubing with a higher concentration of insulin before initiation of standard insulin infusion therapy should accelerate achievement of steady-state insulin delivery and correction of hyperglycemia in ELBW infants.

Blood Glucose↗
PubMed1997

Analysis of nitrate in biological fluids by capillary electrophoresis.

Nitrite and nitrate represent the products of the final pathway of nitric oxide metabolism. These two ions were analyzed by capillary electrophoresis (CE) in serum, cerebrospinal fluid, urine and tissue homogenates by mixing the sample with acetonitrile containing NaBr as an internal standard, followed by centrifugation. The supernatant was injected hydrodynamically on a capillary 50 cm x 75 microns (I.D.) and electrophoresed at 6 kV (reversed polarity) in 1.4% sodium chloride in phosphate buffer for 13 min with detection at 214 nm. In addition to removal of the proteins, acetonitrile caused sample stacking. Urinary nitrate analysis by CE was compared to that by the enzymatic Aspergillus nitrate reductase method, with a correlation coefficient of 0.96.

Acetonitriles↗
PubMed1997

Analysis of small molecules for clinical diagnosis by capillary electrophoresis.

The application of capillary electrophoresis (CE) for the analysis of small molecules in clinical research is growing steadily. Initial studies have dealt with separations of standards or compounds in clean matrices. However, later studies dealt with analysis of those compounds in serum, urine or tissues. Great progress has been accomplished in three areas of clinical interest: organic acids, amino acids and drug analysis. The analysis of these compounds by capillary electrophoresis has several distinct advantages: high resolution, simplicity, versatility and especially low operating costs. In many cases, the sample can be injected directly without complex pretreatment. Most of the described methods have been validated for their precision, linearity and accuracy. In forensic toxicology, the CE has been used for drug identification and as a complementary analytical method.

Diagnostic Techniques and Procedures↗
PubMed1997

Urine protein analysis by capillary electrophoresis.

Increased concentration of proteins in urine as well as abnormal patterns are seen in many disorders such as various renal disorders and light chain disease. At the wavelength of 214 nm used for detection of the peptide bond, numerous compounds interfere in the analysis of urinary proteins. We show that either adsorptive filtration with a wash step or cold ethanol precipitation are two methods which can eliminate many of the interferences. The wash step is rapid, greatly reduces the interfering substances, and decreases the effect of sample matrix. Both of these methods yield results comparable to the traditional agarose method. Capillary electrophoresis (CE) is faster and more cost-effective than agarose electrophoresis.

Electrophoresis, Agar Gel↗
PubMed1994

Late onset endophthalmitis associated with filtering blebs.

A consecutive series of 71 cases of late onset endophthalmitis (defined as onset of symptoms at least 2 weeks after surgery) were reviewed to determine the association of this entity with glaucoma surgery filtering blebs and to identify any predisposing factors. Sixteen cases were associated with filtering blebs and two with inadvertent blebs following cataract surgery. Onset of endophthalmitis ranged from 24 days to 20 years after surgery (mean, 6.9 years). Possible contributing factors included trauma, vitreous wicks, and bleb leak. Twelve cases were culture-positive, with 5 cases of Staphylococcus epidermidis; 2, Staphylococcus aureus; 4, Streptococcus; and 1, Pseudomonas. There were no cases of Hemophilus. The more virulent organisms were generally associated with a poor visual outcome. The organisms recovered in this series were similar to those found in postoperative endophthalmitis not associated with filtering blebs.

Adult↗
PubMed1993

Central nervous system herpesvirus infection in systemic lupus erythematosus: diagnosis by endoretinal biopsy.

A 31-year-old woman with systemic lupus erythematosus (SLE) developed meningoencephalitis, followed by transverse myelitis. The clinical picture was otherwise not consistent with a lupus flare. Extensive diagnostic evaluation was unrevealing. Acute visual loss ensued, associated with an unusual pattern of retinitis. Endoretinal biopsy established the diagnosis of herpesvirus infection. Reinstitution of antiviral therapy, and optic nerve sheath decompression, led to resolution of neurologic deficits and partial return of vision. Our report is the first that describes a patient with SLE with herpes meningoencephalitis, transverse myelitis, and rapidly progressive outer retinal necrosis, diagnosed antemortem by endoretinal biopsy, and successfully treated with acyclovir and optic nerve fenestration.

Acyclovir↗
PubMed1993

Systemic herpetic infection diagnosed by retinal biopsy.

We describe a patient with systemic lupus erythematosus who developed myelopathy, optic neuropathy, retinopathy, and aseptic meningitis unresponsive to immunosuppressive and antimicrobial therapy. Although cultures and brain biopsy were unrevealing, a Herpes virus was suggested by retinal biopsy. The patient recovered dramatically after institution of acyclovir therapy and optic-nerve-sheath decompression. This case demonstrates that herpetic retinitis can occur in an iatrogenically suppressed host and underscores the value of tissue diagnosis.

Adult↗
PubMed1992

A new technique for repositioning and fixating a dislocated intraocular lens.

A new technique for repositioning and fixating a dislocated posterior chamber intraocular lens is described. Using pars plana vitrectomy techniques, the intraocular lens is retrieved and maintained in the plane of the ciliary sulcus. The lens haptics are sutured to the sclera in three positions to avoid recurrent dislocation or torsion of the lens. Intraocular manipulation of sharp needles is avoided. Suture knots are buried in the sclera to minimize the risk of late-onset endophthalmitis.

Aged↗
PubMed1991

An alternative technique of local anesthesia for vitreoretinal surgery.

Retrobulbar anesthesia produces effective local anesthesia for ocular surgery, but significant complications have been reported with its use. To maintain its efficacy and to minimize the risks associated with the passage of a needle behind the eye, we have placed local anesthesia into sub-Tenon's space posteriorly using a blunt irrigating cannula in 100 patients undergoing vitreous or retinal procedures. Posterior Tenon's capsule is opened by blunt dissection, allowing the irrigating cannula to be passed into the posterior sub-Tenon's space for anesthetic injection. The technique was effective in 98 of 100 patients, and no morbidity was associated with its use.

Anesthesia, Local↗
PubMed1991

A new technique of local anesthesia for panretinal photocoagulation.

We report a technique of local anesthetic administration used in 26 consecutive patients undergoing panretinal photocoagulation. A blunt-tipped irrigating cannula delivered 3 cc of anesthetic into the posterior sub-Tenon's space through a small opening in conjunctiva and Tenon's capsule. Immediate anesthesia, with no serious complications, was obtained in 38 of 40 eyes, facilitating administration of rapid, high-intensity laser burns. Although our experience with it is limited, we believe that this technique allows avoidance of many of the potential complications associated with the passage of a needle into the retrobulbar space.

Anesthesia, Local↗
PubMed1976

Spectacle blur.

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Contact Lenses↗