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Biomedical subjects

A V Levin

Publications and source records attributed to A V Levin.

At least 37 records · Page 2Linked to original sources
PubMed2000

A prospective evaluation of anterior transposition of the inferior oblique muscle, with and without resection, in the treatment of dissociated vertical deviation.

BACKGROUND: Anterior transposition of the inferior oblique muscle (ATIO) has become a popular surgical treatment for dissociated vertical deviation (DVD), particularly in patients with coexisting inferior oblique muscle overaction (IOOA). We wanted to assess whether adding a resection improves the outcome compared with standard anteriorization. METHODS: We undertook a prospective, randomized evaluation of ATIO, with and without a 7-mm resection, in patients with DVD of at least 5 PD in one eye. We included 51 eyes of 30 patients, 26 eyes treated with the standard ATIO and 25 treated with a 7-mm resection added. We recorded the size of the preoperative and final DVD, grade of the preoperative and final IOOA, rates of reoperation, and complications. Mean follow-up was 15.4 months in the standard group and 25.0 months in the resection group, with a minimum of 4 months for all cases. RESULTS: The median preoperative and postoperative DVD was 12 PD and 4 PD in the standard group, respectively. This compared with 14 PD and 4 PD, respectively, in the resection group, representing no statistically significant difference in outcome. The presence or absence of IOOA did not influence the result of ATIO for either group. No significant complications of surgery occurred in either group. CONCLUSIONS: ATIO is an effective treatment for DVD and can be used to treat DVD in patients with or without IOOA, with few adverse effects. Our study revealed no advantage to adding a 7-mm resection to the standard procedure.

Adolescent↗
PubMed2000

Molecular characterisation of congenital glaucoma in a consanguineous Canadian community: a step towards preventing glaucoma related blindness.

Glaucoma is a leading cause of irreversible blindness in Canada. Congenital glaucoma usually manifests during the first years of life and is characterised by severe visual loss and autosomal recessive inheritance. Two disease loci, on chromosomes 1p36 and 2p21, have been associated with various forms of congenital glaucoma. A branch of a large six generation family from a consanguineous Amish community in south western Ontario was affected with congenital glaucoma and was studied by linkage and mutational analysis to identify the glaucoma related genetic defects. Linkage analysis using the MLINK component of the LINKAGE package (v 5.1) showed evidence of linkage to the 2p21 region (Zmax=3.34, theta=0, D2S1348 and D2S1346). Mutational analysis of the primary candidate gene, CYP1B1, was done by direct cycle sequencing, dideoxy fingerprinting analysis, and fragment analysis. Two different disease causing mutations in exon 3, 1410del13 and 1505G-->A, both segregated with the disease phenotype. The two different combinations of these alleles appeared to result in a variable expressivity of the phenotype. The compound heterozygote appeared to have a milder phenotype when compared to the homozygotes for the 13 bp deletion. The congenital glaucoma phenotype for this large inbred Amish family is the result of mutations in CYP1B1 (2p21). The molecular information derived from this study will be used to help identify carriers of the CYP1B1 mutation in this community and optimise the management of those at risk of developing glaucoma.

Adolescent↗
PubMed1999

Rapid improvement in the acuity of infants after visual input.

Visual acuity was assessed in 28 human infants who had been deprived of all patterned visual input by cataracts in one or both eyes until they were treated at 1 week to 9 months of age. Immediately after treatment, acuity was no better than that of normal newborns. Acuity improved significantly over the next month, with some improvement apparent after as little as 1 hour of visual input. Unlike findings at older ages, the pattern of results was the same for eyes treated for monocular and for binocular deprivation. The results indicate that patterned visual input is necessary for the postnatal improvement of human visual acuity and that the onset of such input initiates rapid functional development.

Cataract↗
PubMed1999

Early-infantile galactosialidosis: prenatal presentation and postnatal follow-up.

Galactosialidosis (GS) is an autosomal recessive condition caused by combined deficiency of the lysosomal enzymes beta-galactosidase and alpha-neuraminidase. The combined deficiency has been found to result from a defect in protective protein/cathepsin A (PPCA), an intralysosomal protein which protects these enzymes from premature proteolytic processing. The most severe form of GS, the early-infantile form, results in early onset of edema, ascites, visceromegaly, and skeletal dysplasia. We report a case of early-infantile GS in a male infant who presented with nonimmune fetal hydrops (NIH), "coarse" facial appearance, massive fluid-filled inguinal hernias, multiple telangiectasia, and diffuse hypopigmentation; he subsequently developed visceromegaly. The diagnosis of GS was confirmed biochemically and the defect in PPCA characterized at the protein level. Examination of fetal peripheral blood smears sampled at 30 weeks gestation demonstrated vacuolation of lymphocytes, suggesting blood film examination may be a useful screening tool for cases of NIH where a metabolic disorder is suspected. Skeletal radiography at birth demonstrated punctate epiphyses of the femora, calcanei, and sacrum. We present a discussion of and differential diagnosis for this radiographic finding. To the best of our knowledge, this is the first case of early-infantile GS presenting with stippled epiphyses.

Blotting, Western↗
PubMed1999

Alström syndrome: further evidence for linkage to human chromosome 2p13.

Alström syndrome is a rare autosomal recessive disorder characterized by retinal degeneration, sensorineural hearing loss, early-onset obesity, and non-insulin-dependent diabetes mellitus. The gene for Alström syndrome (ALMS1) has been previously localized to human chromosome 2p13 by homozygosity mapping in two distinct isolated populations - French Acadian and North African. Pair-wise analyses resulted in maximum lod (logarithm of the odds ratio) scores of 3.84 and 2.9, respectively. To confirm these findings, a large linkage study was performed in twelve additional families segregating for Alström syndrome. A maximum two-point lod score of 7.13 (theta = 0.00) for marker D2S2110 and a maximum cumulative multipoint lod score of 9.16 for marker D2S2110 were observed, further supporting linkage to chromosome 2p13. No evidence of genetic heterogeneity was observed in these families. Meiotic recombination events have localized the critical region containing ALMS1 to a 6.1-cM interval flanked by markers D2S327 and D2S286. A fine resolution radiation hybrid map of 31 genes and markers has been constructed.

Base Sequence↗
PubMed1999

Tubulointerstitial nephritis and uveitis in children and adolescents. Four new cases and a review of the literature.

We identified 35 cases of tubulointerstitial nephritis and uveitis (TINU), 31 from a MEDLINE search (1966-1996) of the English literature and 4 from our hospital records (1988-1996). To meet the case definition, the patient had to be less than 18 years old and have TINU of unknown cause. Common presenting symptoms included fatigue, weight loss, fever, and abdominal pain. The uveitis was usually anterior and could occur at any time with respect to the onset of the renal disease. Common laboratory features included anemia, increased erythrocyte sedimentation rate, and decreased creatinine clearance. Most patients (33 of 35) had renal biopsies that commonly revealed an intense inflammatory interstitial infiltrate, glomerular sparing, and negative immunofluorescence studies. Of the 35 patients, 26 received systemic corticosteroid therapy (5 of 26 for eye disease); 22 had follow-up for at least 1 year; 13 of 35 patients had a recurrence of their uveitis. The outcome in all 35 cases was normal renal function with no documented visual loss. In conclusion, TINU is a unique syndrome with characteristic clinical features, laboratory changes, and renal biopsy results. Treatment is controversial, and the outcome in children, even if untreated, is excellent.

Adolescent↗
PubMed1999

Cytomegalovirus retinitis in immunosuppressed children.

PURPOSE: To describe the ocular and systemic features of children with cytomegalovirus retinitis and their disease outcomes. METHODS: Review of all cases of cytomegalovirus retinitis diagnosed or treated at a tertiary care pediatric hospital during a 10-year period. RESULTS: Nine immunocompromised children younger than 16 years were diagnosed as having cytomegalovirus retinitis. The underlying causes of immunocompromise were severe combined immunodeficiency syndrome (n = 2), severe combined immunodeficiency syndrome after bone marrow transplantation (n = 1), acquired immunodeficiency syndrome (AIDS) (n = 2), AIDS and previous bone marrow transplantation for leukemia (n = 1), immunosuppressive therapy after renal transplantation (n = 1), chemotherapy for leukemia (n = 1), and congenital cytomegalovirus infection (n = 1). Five children (56%) had symptomatic extraocular cytomegalovirus infection. Only two children reported visual symptoms with cytomegalovirus retinitis at initial examination. Cytomegalovirus retinitis was bilateral in eight children (89%) and involved the posterior pole in at least one eye of all nine children. Four children (44%) died within 10 months of being diagnosed with cytomegalovirus retinitis. The remaining five children were alive, with follow-up ranging from 14 to 70 months. Successful bone marrow transplantation in one child and discontinuation of immunosuppressive medications in two children improved systemic immune function and permitted discontinuation of anticytomegaloviral therapy. CONCLUSION: Pediatric cytomegalovirus retinitis is often asymptomatic and bilateral and involves the posterior pole at initial examination. Recovery of systemic immune function may occur in some children. Evaluation of children at risk and prompt treatment of cytomegalo. virus retinitis are important to prevent long-term visual morbidity.

Adolescent↗
PubMed1999

The epidemiology of pediatric glaucoma: the Toronto experience.

BACKGROUND: This study was conceived to provide an insight into the spectrum of glaucoma in the pediatric population. We also set out to compare the success of disease control and the prognosis for vision within the different diagnostic subgroups. This is the largest single population of children with glaucoma that has been so described and compared. METHODS: The charts of children who were first seen between birth and age 16 years and who attended the Hospital for Sick Children with any form of glaucoma between January 1974 and January 1995 were reviewed and entered into the study. RESULTS: Data are presented for 306 children. Congenital glaucoma was the most common subtype, accounting for 38%. Patients with congenital glaucoma were young, had surgery, and had more operations than any other group except those with aniridia. Goniotomy offered a cure in 47.8% of the patients. A bimodal distribution reflected their visual performance. Patients with aphakic glaucoma, the next most prevalent group (20%), presented at an older age (4.5 years). Surgical intervention was performed in 50% of these children. Nearly all patients with Sturge-Weber syndrome (80%) had surgery. The following glaucoma groups were associated with a poor visual outcome: aniridia, anterior segment developmental anomalies involving the cornea, uveitis with glaucoma other than steroid induced, retinopathy of prematurity, and persistent hyperplastic primary vitreous. Steroid-induced glaucoma and anterior segment dysgenesis, excluding Peters anomaly, had uniformly good outcomes. CONCLUSION: The ability to control glaucoma in childhood and visual prognosis is highly variable. Particular diagnostic categories do consistently well and some do poorly.

Adolescent↗
PubMed1998

Mutation analysis of patients with Hermansky-Pudlak syndrome: a frameshift hot spot in the HPS gene and apparent locus heterogeneity.

Hermansky-Pudlak syndrome (HPS) is a rare, autosomal recessive disorder in which oculocutaneous albinism, bleeding, and lysosomal ceroid storage result from defects of multiple cytoplasmic organelles-melanosomes, platelet-dense granules, and lysosomes. As reported elsewhere, we mapped the human HPS gene to chromosome segment 10q23, positionally cloned the gene, and identified three pathologic mutations of the gene, in patients from Puerto Rico, Japan, and Europe. Here, we describe mutation analysis of 44 unrelated Puerto Rican and 24 unrelated non-Puerto Rican HPS patients. A 16-bp frameshift duplication, the result of an apparent founder effect, is nearly ubiquitous among Puerto Rican patients. A frameshift at codon 322 may be the most frequent HPS mutation in Europeans. We also describe six novel HPS mutations: a 5' splice-junction mutation of IVS5, three frameshifts, a nonsense mutation, and a one-codon in-frame deletion. These mutations define an apparent frameshift hot spot at codons 321-322. Overall, however, we detected mutations in the HPS gene in only about half of non-Puerto Rican patients, and we present evidence that suggests locus heterogeneity for HPS.

Albinism, Oculocutaneous↗
PubMed1998

OA1 mutations and deletions in X-linked ocular albinism.

X-linked ocular albinism (OA1), Nettleship-Falls type, is characterized by decreased ocular pigmentation, foveal hypoplasia, nystagmus, photodysphoria, and reduced visual acuity. Affected males usually demonstrate melanin macroglobules on skin biopsy. We now report results of deletion and mutation screening of the full-length OA1 gene in 29 unrelated North American and Australian X-linked ocular albinism (OA) probands, including five with additional, nonocular phenotypic abnormalities (Schnur et al. 1994). We detected 13 intragenic gene deletions, including 3 of exon 1, 2 of exon 2, 2 of exon 4, and 6 others, which span exons 2-8. Eight new missense mutations were identified, which cluster within exons 1, 2, 3, and 6 in conserved and/or putative transmembrane domains of the protein. There was also a splice acceptor-site mutation, a nonsense mutation, a single base deletion, and a previously reported 17-bp exon 1 deletion. All patients with nonocular phenotypic abnormalities had detectable mutations. In summary, 26 (approximately 90%) of 29 probands had detectable alterations of OA1, thus confirming that OA1 is the major locus for X-linked OA.

Albinism, Ocular↗
PubMed1997

Pediatric cataract management with variations in surgical technique and aphakic optical correction.

PURPOSE: The purpose of the study was to compare the results of three techniques of cataract surgery in children. Two methods included intraocular lens (IOL) implantation and one used contact lens correction of aphakia. DESIGN: Nonrandomized clinical trial. PARTICIPANTS: Seventy-seven eyes of 50 children between the ages of 2 1/2 and 16 years who had cataract surgery for the treatment of uncomplicated cataract. INTERVENTION: Thirty-one eyes underwent a "conventional" style of implantation, and a "phaco-style" of surgery was used in 24 eyes. A contact lens was used as the primary means of aphakic correction in 22 eyes. MAIN OUTCOME MEASURES: The visual results and complications of each type of surgery were compared. RESULTS: Corrected visual acuities did not differ significantly between the three groups 6 months after surgery. The incidence and type of complications were significantly different. Better lens centration, less long-term iris changes, or wound-related problems were observed with "phaco-style" modification of the technique of IOL insertion. CONCLUSIONS: Pediatric IOL insertion eliminated the need for contact lens wear and did not lead to a significantly different corrected visual acuity 6 months after surgery compared with lensectomy with contact lens correction. Adoption of some of the techniques of modern small-incision cataract surgery for pediatric IOL procedures produces a significant reduction in postoperative anterior segment complications compared with a standard limbal approach. Such modifications allow pediatric IOL insertion to be a safe alternative for the correction of pediatric aphakia.

Adolescent↗
PubMed1997

The afferent pupillary defect.

Examination of the pupils is an essential component of both the neurologic and ocular evaluation of a child in the acute care setting. The manifestation of an afferent pupillary defect has significant clinical implications for diagnosis and management. Correctly assessing the pupils for an afferent defect is an important clinical skill for the pediatric emergency physician. An appreciation of the anatomy and understanding of the mechanisms involved in abnormal pupil responses, knowledge of the proper technique of the swinging flashlight test, and an awareness of potential pitfalls in performing this test will aid the physician in the detection of an afferent pupillary defect.

Afferent Pathways↗
PubMed1996

Screening for cytomegalovirus retinitis in children.

OBJECTIVES: To identify immunosuppressed children who are at risk of cytomegalovirus (CMV) retinitis developing and to evaluate the use of laboratory results for identifying this risk. DESIGN: Prospective cohort and retrospective case-control series. SETTING: University hospital pediatric referral center. PATIENTS: Fifty-six consecutive immunocompromised children (ie, the prospective group) with laboratory evidence consistent with acute or recently acquired CMV infection, which was defined as CMV cultured from the blood, urine, nasopharynx, or biopsy specimen, recent seroconversion, a 4-fold increase in the CMV antibody titer, or an antibody titer of 1:512 or greater. Ninety-three immunocompromised children (ie, the retrospective group) with acute CMV or previous CMV exposure, which was defined as a CMV titer of 1:4 or greater and less than 1:512. MAIN OUTCOME MEASURE: Occurrence of CMV retinitis. RESULTS: Cytomegalovirus retinitis developed in 3 children in the prospective group and in 4 children in the retrospective group. The causes of immunosuppression were severe combined immunodeficiency syndrome (n = 2), severe combined immunodeficiency syndrome status post bone marrow transplantation (n = 1), acquired immunodeficiency syndrome (n = 1), and acquired immunodeficiency syndrome status post bone marrow transplantation for leukemia (n = 1), renal transplantation (n = 1), and chemotherapy for leukemia (n = 1). Cytomegalovirus retinitis was associated with a positive CMV culture result from the urine (P = .03) or nasopharynx (P < .001) in the retrospective group. In the retrospective group, one child with congenital CMV infection and CMV retinitis was excluded from analysis because laboratory tests for CMV were not obtained prior to ganciclovir therapy. CONCLUSIONS: Cytomegalovirus retinitis is uncommon in children compared with adults; it occurred in 5% of the children in our series. A screening ophthalmologic examination should be considered in immunocompromised children with positive CMV laboratory results, particularly positive results of urine or nasopharynx cultures.

Adolescent↗
PubMed1996

Natural history of Alström syndrome in early childhood: onset with dilated cardiomyopathy.

Alström syndrome is an autosomal recessive disorder characterized by cone-rod dystrophy, obesity, hearing impairment, and diabetes caused by insulin resistance. By reviewing the charts of eight patients followed for periods of 2 to 22 years, we established the natural history of this syndrome during childhood. Five patients, in four families, were seen between the ages of 3 weeks and 4 months with a dilated cardiomyopathy, a previously unrecognized feature of the syndrome. Photophobia and nystagmus were first documented in the eight patients between the ages of 5 months and 15 months. In all patients, electroretinography initially showed a severe cone impairment with mild (2/8) or no (6/8) rod involvement. Electroretinograms, obtained again at ages 9 to 22 years for four patients, revealed extinguished rod-and-cone responses. Obesity developed during childhood in seven patients, in at least three of them before age 2 years. Hearing impairment (5/8) and diabetes/glucose intolerance (4/8) were diagnosed at the end of the first decade or during the second decade. This constellation of features should facilitate early diagnosis of the syndrome.

Adolescent↗