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L J Alexander

Publications and source records attributed to L J Alexander.

At least 55 records · Page 3Linked to original sources
PubMed1995

Porcine SINE-associated microsatellite markers: evidence for new artiodactyl SINEs.

Approximately 24% (170/710) of porcine (dG-dT)n.(dC-dA)n microsatellites isolated in our laboratory are associated with a previously described porcine Short Interdispersed Element (SINE) termed PRE-1 SINE. Another 5.6% (40/710) of the microsatellites were adjacent to two previously unidentified SINE sequences, which we have designated ARE-1P (Artiodactyl Repetitive Element-1 Porcine) and ARE-2P. The ARE repeats were also found in bovine microsatellite and genomic sequences in the GenBank database. Genotypic information was obtained from 68.9% of primers where at least one primer sequence was obtained from the PRE-1 SINE and 66.6% of primer pairs designed from the ARE SINEs. The use of primers derived from SINEs significantly increases the number of primer pairs available for genetic linkage studies in swine.

Animals↗
PubMed1995

The roles of semantic networks and search efficiency in verbal fluency performance in intractable temporal lobe epilepsy.

Two competing hypotheses (i.e., disruption of semantic networks vs. search inefficiency) concerning the mechanisms underlying impaired semantic verbal fluency in temporal lobe epilepsy (TLE) were tested within a single paradigm. Reports that semantic verbal fluency is more impaired in left than right TLE groups were confirmed by the findings that the left TLE group produced fewer words on a supermarket fluency task than did the normal control (NC) group, and that the performance of the right TLE group was intermediate to that of the left TLE and NC groups. Because both TLE groups generated fewer words per category of supermarket items sampled, and produced a higher ratio of category labels relative to category exemplars than did the NC group, it can be surmised that TLE disrupts semantic memory networks. The findings did not support the competing hypothesis that reduced semantic verbal fluency in TLE is a manifestation of inefficient search/retrieval strategies, possibly associated with distal frontal lobe pathophysiology. Specifically, the TLE and NC groups did not differ significantly in their mean number of perseverations, intrusions, or search efficiency (operationalized as the ratio of the number of shifts between categories to the number of categories sampled).

Adult↗
PubMed1995

Directed integration of the physical and genetic linkage maps of swine chromosome 7 reveals that the SLA spans the centromere.

The first integrated physical and genetic linkage map encompassing the entire swine chromosome 7 (SSC7) reveals that the porcine MHC (SLA) spans the centromere. A SLA class II antigen gene lies on the q arm, whereas class I and III genes lie on the p arm, suggesting that the presence of a centromere within the SLA does not preclude a functional complex. The SLA appears smaller than other mammalian MHC, as the genetic distance across two class I, three class II, and three class III SLA gene markers is only 1.1 cM. There are significant variations in recombination rates as a function of position along the chromosome, and the SLA lies in the region with the lowest rate. Furthermore, the directed integration approach used in this study was more efficient than previous efforts that emphasized the screening of large insert libraries for random microsatellites.

Animals↗
PubMed1995

Clinical implications of intra- and inter-reader agreement in four different automated visual fields.

BACKGROUND: This study was designed and conducted to examine the degree of inter- and intra-reader agreement when four readers evaluate visual fields in patients known to have glaucoma and patients known to not have glaucoma. METHODS: Fifty-three patients known to have glaucoma and 60 patients known not to have glaucoma were selected randomly from a population at the University of Alabama at Birmingham School of Optometry. Four visual fields were performed on each patient, non-dilated, with the proper correction in place. The fields were performed on three different instruments by technicians who were unaware of the diagnostic status of the patient. Four independent (blinded) clinicians read the visual fields and judged them as: "glaucoma field defect," "no glaucoma field defect," and "poor reliability-cannot judge." RESULTS: Statistical analysis revealed that a single reader's interpretation of four different types of visual fields are very different from, are poorer than, and are more consistent than are the four readers' interpretations of a single type of visual field. The analysis also shows that the readers consistently underestimated the number of glaucoma patients with one instrument and overestimated the number with another. CONCLUSIONS: This results suggest that a single visual field will discriminate patients with glaucoma with an accuracy in the 70 to 75 percent range. For one of the instruments, the shorter protocol was almost as effective in discriminating glaucomatous fields as the longer protocol. This study also suggests that repeating the visual fields or analysis of a single field by two readers improves reliability.

Aged↗
PubMed1994

A conceptual database model for genomic research.

We describe a conceptual model for genome databases that facilitates the process of building, maintaining, and disseminating physically anchored genetic linkage maps. The model has been implemented as a relational database at the Roman L. Hruska U.S. Meat Animal Research Center (MARC). Development of consensus maps using disparate data from different reference pedigrees or laboratories is supported. The model is of use to quantitative and population geneticists interested in loci that affect phenotypes and marker-assisted selection, and it is sufficiently flexible for centralized, species genome databases facilitating comparative mapping. The MARC genome database is used to assemble, maintain, and disseminate physically anchored genetic linkage maps for cattle, swine, and sheep currently based on more than 100,000 genotypes from 1,000 markers. Integrated with linkage analysis software, this database permits frequent updates of physically anchored genetic linkage maps.

Algorithms↗
PubMed1994

A microsatellite linkage map of the porcine genome.

We report the most extensive genetic linkage map for a livestock species produced to date. We have linked 376 microsatellite (MS) loci with seven restriction fragment length polymorphic loci in a backcross reference population. The 383 markers were placed into 24 linkage groups which span 1997 cM. Seven additional MS did not fall into a linkage group. Linkage groups are assigned to 13 autosomes and the X chromosome (haploid n = 19). This map provides the basis for genetic analysis of quantitative inheritance of phenotypic and physiologic traits in swine.

Animals↗
PubMed1994

Congenital optic nerve hypoplasia.

Congenital optic nerve hypoplasia (CONH) is an increasingly recognized cause of low vision in children. The spectrum of ophthalmoscopic and clinical presentations of CONH is described here with illustrative cases. Some children with unilateral CONH develop a secondary, functional amblyopia that may respond to patching during visual development. Children with bilateral CONH, poor vision and nystagmus usually present early and have a high risk of exhibiting central nervous system (CNS) malformations and treatable endocrine deficiencies.

Adolescent↗
PubMed1994

RFLP and linkage analysis of the porcine casein loci--CASAS1, CASAS2, CASB and CASK.

Restriction fragment length polymorphisms (RFLPs) were revealed at the porcine casein loci with the following combinations of restriction endonucleases and porcine cDNA clones: alpha s1-casein (TaqI); alpha s2-casein (BamHI); and beta-casein (SacI). These RFLPs were shown to be under simple monogenic control by segregation analysis of two- and three-generation families. The CASAS1, CASAS2 and CASB casein loci were also shown to be linked with no recombinant haplotypes observed amongst 77 meioses in Large White and Meishan F1 and F2 crosses. No recombinants were observed in a further 106 meioses that were informative for linkage between CASAS1 and CASAS2.

Alleles↗
PubMed1994

Use of direct in situ single-copy (DISC) PCR to physically map five porcine microsatellites.

Direct in situ single-copy polymerase chain reaction (DISC-PCR) was used to assign and orient a linkage group to pig chromosome 1. Five microsatellites were analyzed, and all five were successfully localized using this procedure. Physical data were used to orient the linkage group with respect to the centromere and estimate the amount of coverage of chromosome 1. There was excellent concordance between the physical and linkage maps. The linear order of the microsatellites was identical, and relative distances were similar. All markers were located on the long arm of chromosome 1. Coverage was estimated at about 32%. Thus, DISC-PCR rapidly and easily assigned and ordered microsatellite markers for which large genomic clones do not exist.

Animals↗
PubMed1994

Protocols for co-management.

Co-management by optometrists and ophthalmologists requires a written expression of the protocol for examination, treatment, and follow-up of patients. The protocol should also describe how and when information is to be shared between practitioners. To facilitate the communication process, standard forms should be adopted for use by all practitioners. Example protocols and sample forms are provided for the most common types of clinical situations in which co-management is required: postoperative care of cataract patients; treatment of glaucoma patients; and preoperative and postoperative management of radial keratotomy patients.

Eye Diseases↗
PubMed1994

Eye care for patients with diabetes in the state of Florida: status in 1988.

BACKGROUND: More than 14 million Americans are suspected of having diabetes with fewer than half of those currently diagnosed. Diabetes is the number one cause of new cases of blindness in persons 20-74 years of age. METHODS: This study was performed in the state of Florida to determine both the accessibility of eye care as well as the similarities and differences in the practice behavior patterns of optometrists and ophthalmologists for patients with diabetes. RESULTS: The results of two surveys sent to both the Florida Society of Ophthalmology and the Florida Optometric Association by the Florida Diabetes Retinopathy Task Force (FDRTF) were analyzed. The results indicated better accessibility for diabetics to optometrists (81 percent of counties) than ophthalmologists (55 percent of counties). In addition, the results demonstrated strong similarities in practice patterns between the two professions. The results also indicate that primary care medical doctors do not routinely take advantage of the practicing optometrist for the examination of the diabetic patients in their practices. CONCLUSIONS: The poor utilization of the primary care optometrist creates a gap in the health care delivery for the patient with diabetes. This gap may contribute to the increase in the complication of diabetic retinopathy.

Diabetic Retinopathy↗
PubMed1993

Age-related macular degeneration: the current understanding of the status of clinicopathology, diagnosis and management.

BACKGROUND: This paper represents an up-to-date review of the current thoughts regarding the etiopathogenesis and management of the various varieties of age-related macular degeneration (ARMD). METHODS: Included is a look at the epidemiology as well as the clinicopathologic basis for the development of the degenerative process. CONCLUSIONS: The clinicopathologic basis for development of ARMD is divided into drusen, lipofuscin development, solar radiation effects, photochemical damage and mediation by antioxidants, choroidal neovascularization, scarification, and retinal pigment epithelial detachment. The clinical presentation of both non-exudative and exudative ARMD is discussed with synopses of the mimickers of both outlined in the text. RESULTS: Current accepted methods of therapy are discussed including; laser intervention, surgical removal of membranes, and investigational modes of treatment including antioxidants. Specific management protocol is discussed based on the current knowledge base.

Aged↗
PubMed1993

Hypertension update.

BACKGROUND: National Health Care Issues-II deals with two reports of tremendous importance to national health, the results of the Systolic Hypertension in the Elderly Program (SHEP) and the results of the Trials of Hypertension Prevention, Phase I (TOHP-I). Both of these issues have tremendous impact on the systemic and ocular morbidity and mortality associated with hypertension. METHODS: The SHEP report addresses the effects of treatment of isolated systolic hypertension (+160 mmHg) in patients 60 years of age and older. RESULTS: The results indicate that stepped-treatment (initially with a low dosage of chlorthalidone) of these levels of systolic blood pressure had a positive effect on morbidity and mortality. The TOHP-I report addressed the short term feasibility and efficacy of modification of blood pressure by seven non-pharmacologic interventions (LIFE STYLE MODIFICATION). CONCLUSIONS: Contrary to popular beliefs and myths, the only significant blood pressure reductions were attained with modest reductions in weight and sodium intake. These reductions translate to decreased morbidity and mortality.

Age Factors↗
PubMed1992

The sequence of a porcine cDNA encoding alpha-lactalbumin.

A cDNA clone encoding porcine alpha-lactalbumin (alpha LA) was isolated and sequenced. The longest clone was 688 nucleotides (nt) long and encoded a preprotein of 141 amino acids (aa) including a leader peptide of 19 aa. The porcine cDNA exhibited a nt similarity of between 72.2%-83.5% to other alpha LA cDNAs and an aa similarity of between 50.8%-85.2% with other alpha LA aa sequences. The derived aa sequence varied at three positions from a previously reported sequence for porcine alpha LA obtained by direct aa sequencing.

Amino Acid Sequence↗
PubMed1992

Cloning and sequencing of the porcine lactoferrin cDNA.

cDNA clones encoding the entire porcine lactoferrin protein were isolated and sequenced. The porcine lactoferrin cDNA sequence presented here is 2259bp in length and encodes a leader peptide of 19 amino acids and a mature protein of 684 amino acids. Comparisons with other lactoferrins indicate a single glycosylation site. The iron- and anion-binding sites, and the cysteine residues involved in disulphide bonds, are conserved between the lactoferrin proteins.

Amino Acid Sequence↗
PubMed1992

Sequence of porcine beta-lactoglobulin cDNA.

cDNAs encoding porcine beta-lactoglobulin were isolated and sequenced. The porcine beta-lactoglobulin cDNA is 768bp in length and encodes a pre-protein of 178 amino acids. One additional cDNA clone was found to encode an additional amino acid (lysine) in the mature protein.

Amino Acid Sequence↗
PubMed1992

The sequence of porcine alpha s1-casein cDNA: evidence for protein variants generated by altered RNA splicing.

A cDNA library was constructed from mRNA isolated from lactating porcine mammary gland and screened with a bovine alpha s1-casein cDNA clone. Three classes of cDNA isolated varied in the number of bases within the coding region. The full length porcine alpha s1-casein cDNA is 1124bp and codes a preprotein of 206 amino acids. The other two classes of alpha s1-casein cDNA lacked 18bp and 60bp respectively when compared to the 1124-bp cDNA sequence. PCR amplification confirmed the presence of these sequences in total RNA. These differences appear to be due to altered RNA splicing.

Amino Acid Sequence↗