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Biomedical subjects

Daniel J Hogan

Publications and source records attributed to Daniel J Hogan.

9 recordsLinked to original sources

Macronuclear molecules encoding actins in spirotrichs.

The nucleotide sequences of 16 newly reported and 8 previously reported actin-encoding macronuclear DNA molecules in spirotrichs have been compared. As described for the eight previously reported molecules, the first 50 bases (noncoding) inside the telomere at both 5' strands in additional actin molecules are purine-rich. This anomalous base composition might serve as a signal to identify macronuclear molecules in micronuclear DNA during development. The 50-base segment upstream of the ATG in the 5' leaders of the actin molecules contains extensive, conserved sequence motifs that are possibly promoter elements. The 3' noncoding trailers contain virtually no conserved sequence motifs. With one exception, the 3' trailers contain a second stop codon (TGA) 36 bases on average downstream of the primary stop codon. Excluding Moneuplotes crassus, amino acid identities in actin I range from 78 to 100%, with variations distributed nonrandomly along the sequence. Phylogenetic trees based on the actin nucleotide sequences of 22 spirotrichs define the evolutionary relationships of their actin-encoding molecules. The actin phylogeny, while well supported by posterior probabilities, does not always coincide with the phylogeny defined in rDNA analyses or classical taxonomic classifications.

3' Untranslated Regions↗

Phylogenetic relationships among 28 spirotrichous ciliates documented by rDNA.

The contiguous sequence of the SSU rDNA, ITS 1, 5.8S, ITS 2, and approximately 1370 bp at the 5(') end of the LSU rDNA was determined in 25 stichotrichs, one oligotrich, and two hypotrichs. Maximum parsimony, neighbor-joining, and quartet-puzzling analyses were used to construct individual phylogenetic trees for SSU rDNA, for LSU rDNA, and ITS 1+5.8S+ITS 2, as well as for all these components combined. All trees were similar, with the greatest resolution obtained with the combined components. Phylogenetic relationships were largely consistent with classical taxonomy, with notable disagreements. DNA sequences indicate that Oxytricha granulifera and Oxytricha longa are rather distantly related. The oligotrich, Halteria grandinella, is placed well within the order Stichotrichida. Uroleptus pisces and Uroleptus gallina probably belong to different genera. Holosticha polystylata (family Holostichidae) and Urostyla grandis (family Urostylidae) are rather closely related. These rDNA sequence analyses imply the need for some modifications of classical taxonomic schemes.

Animals↗

Granuloma annulare and malignant neoplasms.

The relationship between granuloma annulare (GA) and malignant neoplasms is uncertain. Several case reports and clinical correlation studies have addressed this issue; however, no review articles have summarized those reported cases and statistically analyzed the association. Fourteen case reports and two correlation studies directly addressing the relationship of GA and malignant neoplasms were found from the Medline database from 1966-2001. A total of 16 cases from case reports were available with the mean age of 54. Most of the GA patients had an atypical clinical presentation. The time between the onset of GA and the discovery of the malignant neoplasms varied from 18 months before (median = 5 months) to 7 years after (median = 42 months). More than half of those cases were associated with lymphoma. No definite relationship was found between GA and malignant neoplasms. Older patients with skin lesions not clinically typical of GA but that histologically resemble classic GA, may be considered for investigation of underlying malignant lymphoma or other malignancies.

Adult↗

A PIWI homolog is one of the proteins expressed exclusively during macronuclear development in the ciliate Stylonychia lemnae.

In the course of macronuclear differentiation in spirotrichous ciliates massive DNA reorganization processes take place, which include splicing, cutting, rearranging and eliminating specific DNA sequences. In order to identify genes involved in these processes we took advantage of suppression subtractive hybridization. We have identified three transcripts that are exclusively expressed during macronuclear development in the ciliate Stylonychia lemnae. Two of the three differentially expressed mRNAs we have analyzed encode for novel proteins. One gene, mdp1 [macronuclear development protein 1 (MDP1)], encodes a homolog of the PIWI protein family. PIWI proteins are involved in germline differentiation processes and RNA silencing in worms, flies, mice, humans and in plants. Possible functions of the S.lemnae PIWI related protein MDP1 in the regulation of macronuclear development will be discussed.

Amino Acid Sequence↗

Personal observation of skin disorders in malnutrition.

This is a description of some unknown skin disorders found by a physician inmate in a concentration camp, 1958 to 1962. After prolonged semistarvation and ultraheavy physical labor, skin lesions developed among the inmates including cutaneous pigmentation overlying bony prominence, buccal membrane pigmentation, palmoplantar keratoderma with fissures, palmar crease clefts, nail layering, intra-nail hemorrhage, and so on. These lesions responded dramatically to nutrition therapy, including dietary improvement, yeast administration, or thiamin injection. Thiamin deficiency was confirmed to be one of major etiologic factors, whereas the deficiency of niacin or riboflavin also played a part. In the pediatric case with palmar crease clefts, both thiamin and niacin were dramatically effective. No laboratory data could be provided.

Adolescent↗

Dermatologic look- or sound-alike medications.

Medication errors contribute substantially to patient injury and death, with 25% of these errors attributed to drug names that look or sound alike. This article was written to heighten the awareness of dermatologists and related health care professionals of confusing dermatologic drug names and includes a table of 166 look- and sound-alike drug names. Measures to decrease medication errors due to confusing drug nomenclature in dermatology are suggested in order to maximize patient safety.

Drug Labeling↗