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Biomedical subjects

D Mackey

Publications and source records attributed to D Mackey.

29 records · Page 2Linked to original sources
PubMed1991

Leber hereditary optic neuropathy: identification of the same mitochondrial ND1 mutation in six pedigrees.

Biochemical and molecular genetic evidence is presented that in six independent pedigrees the development of Leber hereditary optic neuropathy (LHON) is due to the same primary mutation in the mitochondrial ND1 gene. A LHON family from the Newcastle area of Great Britain was analyzed in depth to determine the mitochondrial genetic etiology of their disease. Biochemical assays of mitochondrial electron transport in organelles isolated from the platelet/white-blood-cell fraction have established that the members of this family have a substantial and specific lowering of flux through complex I (NADH-ubiquinone oxidoreductase). To determine the site of the primary mitochondrial gene mutation in this pedigree, all seven mitochondrial complex I genes were sequenced, in their entirety, from two family members. The primary mutation was identified as a homoplasmic transition at nucleotide 3460, which results in the substitution of threonine for alanine at position 52 of the ND1 protein. This residue occurs within a very highly conserved hydrophilic loop, is invariantly alanine or glycine in all ND1 proteins, and is adjacent to an invariant aspartic acid residue. This is only the second instance in which both a biochemical abnormality and a mitochondrial gene mutation have been identified in an LHON pedigree. The sequence analysis of the ND81 gene was extended to a further 11, unrelated LHON pedigrees that had been screened previously and found not to carry the mitochondrial ND4/R340H mutation. The ND1/A52T mutation at nucleotide 3460 was found in five of these 11 pedigrees. In contrast, this sequence change was not found in any of the 47 non-LHON controls. The possible role of secondary complex I mutations in the etiology of LHON is also addressed in these studies.

Amino Acid Sequence↗
PubMed1991

A 39-year-old man with acute hemolytic crisis secondary to intravenous injection of hydrogen peroxide.

The diagnosis of cancer or its recurrence is often emotionally devastating for patients and those close to them. People may have a great deal of difficulty accepting the diagnosis and may seek others' opinions about the best course of treatment. When a physician projects that there is no hope, or if a cure is no longer probable, the patient and those close to him or her may feel helpless and hopeless. Given the resultant psychologic turmoil, the patient may be led to try unproven methods. Such methods, often referred to as "cancer quackery," represent a person's attempt to reassert personal control in response to these feelings of helplessness and hopelessness. Cancer quackery involves about $2 billion each year in the United States alone. One study demonstrated that approximately 39% of the pediatric outpatients studied had either tried, considered, or received recommendations for unproven methods of cancer treatment. Laetrile and faith healing were the most frequent methods used. One of the most recent of the unproven methods of cancer treatment that have been shown to cause life-threatening complications is IV injection of hydrogen peroxide. The scientific rationale behind this procedure is still unclear, but the side effects are clearly life threatening.

Adult↗
PubMed1989

X-linked megalocornea: close linkage to DXS87 and DXS94.

In a family in which X-linked megalocornea is segregating, the disease locus was found to be closely linked to DXS87 (zeta max = 3.91, theta max = 0.00) and DXS94 (zeta max = 3.34, theta max = 0.00) in Xq21.3-q22.

Corneal Diseases↗
PubMed1987

Mycetoma in Saudi Arabia.

The clinical and microbiological features of 31 cases of mycetoma seen in 8 years at a Riyadh hospital are described. Eighteen were due to Streptomyces somaliensis, 10 to Madurella mycetomatis and one each to Actinomadura madurae, Nocardia asteroides, and an unidentified species of Cladosporium. No immune defects were detected in the patients. Eleven had osteolytic lesions and 17 required surgery. Only seven patients were cured. Streptomyces infections were seen from all parts of Saudi Arabia outside the Rub Al Khali, but Madurella occurred mostly in highland regions where rainfall is higher.

Actinomycetaceae↗
PubMed1982

Antibiotic loaded plaster of Paris pellets: an in vitro study of a possible method of local antibiotic therapy in bone infection.

Plaster of Paris is an effective ancillary treatment in the surgery of infected cavities in bone. It is well tolerated and spontaneously absorbed over a period of weeks to months, being replaced by bone of normal architecture. It effectively obliterates much of the dead space, leaving little room for hematoma formation. It would appear logical to treat local infection, especially involving rigid walled cavities, by a locally diffused antibiotic. When incorporated into plaster of Paris pellets, two antibiotics, Fucidin and gentamicin, are capable of prolonged local release in bacteriocidal concentrations. On the basis of in vitro observations on bacterial cultures, it is proposed that antibiotic-plaster of Paris pellets might be a simple adjuvant technique to good surgical debridement in the treatment of bone infection. Plaster of Paris has the practical advantage over acrylic cement beads containing antibiotics in that it is resorbed and would not need a subsequent operation to be moved.

Anti-Bacterial Agents↗
PubMedDate not supplied

Skin clues in the diagnosis of life-threatening infections.

Skin lesions, an important clue to the cause of septicemia, result from five main processes: (1) disseminated intravascular coagulation and coagulopathy; (2) direct vascular invasion and occlusion by bacteria or fungi; (3) immune vasculitis and immune complex formation; (4) emboli from endocarditis; and (5) vascular effects of toxins. Disseminated intravascular coagulation probably plays only a minor role in pathogenesis. Vascular invasion by bacteria may result in a severe inflammatory reaction, as in meningococcemia, or in a minimal reaction, as in ecthyma gangrenosum. Gram-stained smears of scrapings from the base of skin lesions--a frequently neglected procedure--is an important diagnostic adjunct. Skin biopsies are particularly important in the diagnosis of Rocky Mountain spotted fever and infections caused by Candida.

Antigen-Antibody Complex↗