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Biomedical subjects

T Brown

Publications and source records attributed to T Brown.

At least 325 records · Page 18Linked to original sources
PubMed1989

[Three-dimensional measurement of the maxillary first molar in Australian whites].

The occlusal surfaces of upper first molars of Australian Whites were measured in three dimensions with the aid of moiré contourography. The dental casts had been collected from Australian White twins who were considered to be of European stock and the casts housed in the Department of Dentistry, The University of Adelaide, South Australia. In the present study, our first aim was to describe the three-dimensional features of occlusal surfaces of molars in Australian whites. One cast was selected from each monozygotic twin pair at random. A total of 24 males and 15 females were photographed. The results obtained in the present study were compared with those of other human populations previously reported. Cusp height of Australian Whites showed intermediate mean values among 8 populations, but mean intercuspal distances were smaller. This feature, such as small size of occlusal surface but relatively high cusps, also found in Dutch and Asiatic Indian. Mean cusp heights in this population of showed similar values between sexes. Mean differences were insignificant as in Asiatic Indian, Australian Aboriginals, and Bantu unlike the Mongoloid, Japanese and Eskimo populations, where there were significant sex differences in cusp heights. This sexual dimorphism in cusp height among human populations is discussed phylogenetically and functionally.

Australia↗
PubMed1989

Unlicensed persons in patient care settings. Administrative, policy, and ethical issues.

The current nursing shortage is a supply-and-demand problem. Factors contributing to the shortage include increased hospital use of RNs; decreased nursing school enrollment; increased demand for RNs outside of hospitals in skilled nursing facilities, health maintenance organizations, and home health care programs; noncompetitive salaries; and lack of autonomy. The nursing shortage has triggered the development and implementation of programs to prepare non-nurse bedside technicians to work in partnership with RNs. The functions of these unlicensed persons range from housekeeping, stocking, and clerical responsibilities to several technical treatments that once fell within the role responsibilities of registered or practical nurses. The partnerships between unlicensed persons and RNs in patient care settings have given rise to several administrative, policy, and ethical issues for nurse leaders. An ethical analysis, based on the application of ethical principles and moral dilemmas found in "The Parable of the Sadhu," offers some guidelines to nursing leaders in the administrative and policy decisions inherent in the development and retention of licensed persons in patient care settings. Some conclusions drawn from the ethically based questions are: The acquisition and retention of RNs and other licensed caregivers should take precedence over the development of programs for non-nurse bedside technicians. RNs in partnership with unlicensed persons in patient care settings must know what they can legitimately delegate. The RN has personal responsibility for ensuring optimal standards of nursing practice in the delegation of duties. The partnership between professional nurses and unlicensed persons must be a participative effort, not a manipulative or coercive one. In putting the organizational principle of subsidiarity into practice, decision makers will be able to maintain respect for human dignity and the uniqueness of patients and caregivers as well. The development and retention of unlicensed persons in patient care settings depends on a well-developed personal ethic that needs to be congruent with the mission, philosophy, and codes of ethics of national and local health care organizations.

Allied Health Personnel↗
PubMed1988

Similarity of the E1 subunits of branched-chain-oxoacid dehydrogenase from Pseudomonas putida to the corresponding subunits of mammalian branched-chain-oxoacid and pyruvate dehydrogenases.

The genes encoding proteins responsible for activity of the E1 component of branched-chain-oxoacid dehydrogenase of Pseudomonas putida have been subcloned and the nucleotide sequence of this region determined. Open reading frames encoding E1 alpha (bkdA1, 1233 bp) and E1 beta (bkdA2, 1020 bp) were identified with the aid of the N-terminal sequence of the purified subunits. The Mr of E1 alpha was 45,158 and of E1 beta was 37,007, both calculated without N-terminal methionine. The deduced amino acid sequences of E1 alpha and E1 beta had no similarity to the published sequences of the E1 subunits of pyruvate and 2-oxoglutarate dehydrogenases of Escherichia coli. However, there was substantial similarity between the E1 alpha subunits of Pseudomonas and rat liver branched-chain-oxoacid dehydrogenases. In particular, the region of the E1 alpha subunit of the mammalian branched-chain-oxoacid dehydrogenase which is phosphorylated, was found to be highly conserved in the Pseudomonas E1 alpha subunit. There was also considerable similarity between the E1 beta subunits of Pseudomonas branched-chain-oxoacid dehydrogenase and human pyruvate dehydrogenase.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1988

Comparison of the amino acid sequences of the transacylase components of branched chain oxoacid dehydrogenase of Pseudomonas putida, and the pyruvate and 2-oxoglutarate dehydrogenases of Escherichia coli.

The nucleotide sequence of bkdB, the structural gene for E2b, the transacylase component of branched-chain-oxoacid dehydrogenase of Pseudomonas putida has been determined and translated into its amino acid sequence. The start of bkdB was identified from the N-terminal sequence of E2b isolated from branched-chain-oxoacid dehydrogenase of the closely related species, P. aeruginosa. The reading frame was composed of 65.5% G + C with 82.3% of the codons ending in G or C. There was no intergenic space between bkdA2 and bkdB. No codons requiring minor tRNAs were utilized and the codon bias index indicated a preferential codon usage. The bkdB gene encoded 423 amino acids although the N-terminal methionine was absent from E2b prepared from P. aeruginosa. The relative molecular mass of the encoded protein was 45,134 (45,003 minus methionine) vs 47,000 obtained by SDS/polyacrylamide gel electrophoresis. There was a single lipoyl domain in E2b compared to three lipoyl domains in E2p, and one domain in E2o, the transacylases of pyruvate and 2-oxoglutarate dehydrogenases of Escherichia coli respectively. There was significant similarity between the lipoyl domain of E2b and of E2p and E2o as well as between the E1-E2 binding domains of E2b, E2p and E2o. There was no similarity between the E3 binding domain of E2b to E2p and E2o which may reflect the uniqueness of the E3 component of branched-chain-oxoacid dehydrogenase of P. putida. The conclusions drawn from these comparisons are that the transacylases of prokaryotic pyruvate, 2-oxoglutarate and branched-chain-oxoacid dehydrogenases descended from a common ancestral protein probably at about the same time.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1988

Contours of maxillary molars studied in Australian aboriginals.

Distances from the central pit to the perimeter of the crown of permanent upper molars were measured on standardized occlusal photographs of dental casts representing 210 male and 181 female Aboriginals from Yuendumu in the Northern Territory of Australia. In both males and females the first molar was the largest tooth but it showed least variability. Variabilities of the distances tended to be greater for radii constructed in the buccolingual direction than for the transverse mesiodistal radii. The most marked size reduction in the molar series from first to third related to the distolingual part of the crown, which was also the most variable region. Size differences between molars in the mesial contour radii were not marked. Sexual dimorphism was evident in most crown radii, being most marked for the second molar.

Australia↗
PubMed1988

Clinical, pathological, and neurochemical changes in dementia: a subgroup with preserved mental status and numerous neocortical plaques.

Postmortem examination was performed on 137 residents (average age 85.5 years) of a skilled nursing facility whose mental status, memory, and functional status had been evaluated during life. Seventy-eight percent were demented using conservative criteria; 55% had characteristic Alzheimer's disease. Choline acetyltransferase and somatostatin were significantly reduced in the brains of patients with Alzheimer's disease as compared with age-matched nursing home control subjects, although the degree of the reduction was less severe than found in subjects less than 80 years of age. Ten subjects whose functional and cognitive performance was in the upper quintile of the nursing home residents, as good as or better than the performance of the upper quintile of residents without brain pathology (control subjects), showed the pathological features of mild Alzheimer's disease, with many neocortical plaques. Plaque counts were 80% of those of demented patients with Alzheimer's disease. Choline acetyltransferase and somatostatin levels were intermediate between controls and demented patients with Alzheimer's disease. The unexpected findings in these subjects were higher brain weights and greater number of neurons (greater than 90 micron 2 in a cross-sectional area in cerebral cortex) as compared to age-matched nursing home control subjects. These people may have had incipient Alzheimer's disease but escaped loss of large neurons, or alternatively, started with larger brains and more large neurons and thus might be said to have had a greater reserve.

Aged↗
PubMed1988

Comparison of rate of annual change of mental status score in four independent studies of patients with Alzheimer's disease.

Longitudinal studies of subjects with autopsy-proven Alzheimer's disease in one skilled nursing home and of clinically diagnosed cases (NINCDS/ADRDA criteria) in three community cohorts are compared with regard to the annual rate of change in the error score of the Blessed information-memory-concentration test (IMC) in which the maximum number of errors possible is 33. The four cohorts differed significantly from each other in regard to age, education, sex, and the degree of dementia as measured by the initial IMC score. Subjects spanned the age range of 52 to 96 years and had 2 to 20 years of education. The rate of change in error score per year was similar whether the initial error score was 0 to 7, 8 to 15, or 16 to 23; however, the rate was reduced when the initial error score was 24 or above, due to a ceiling effect of the test. Among subjects with initial IMC scores less than 24, the annual rate of change varied considerably. However, the mean annual rate of change, 4.4 errors (SD +/- 3.6, SEM +/- 0.3) per year, was independent of residence in a nursing home, location of the study site, and of the patient's sex or education. Of particular importance was the finding that the rate of change in mental test score was independent of age. It can be concluded that the rate of cognitive deterioration in patients with Alzheimer's disease is quite variable among individuals and is independent of the patient's age and whether the patient resides in the community or in a nursing home.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Principal component analysis of intercusp distances on the lower first molars of three human populations.

The distances between the five main cusps of lower first molars were measured on moiré photographs of casts obtained from Japanese, Dutch and Australian Aboriginal children. Principal component analysis of the intercusp distances, log transformed and standardized so that average tooth size was held constant, revealed three sources of shape variation in cusp topography. All populations were similar for scores on component 1 which was concerned with variations in the position of the hypoconulid. The Dutch had lowest scores on component 2 indicating small buccolingual distances compared with mesiodistal, whereas the Australian Aboriginals had the lowest mean score on component 3, expressing the distances between metaconid, entoconid and hypoconulid.

Asian People↗
PubMed1988

The effects of four drug regimens on sister chromatid exchange frequency in patients with lymphomas.

Patients undergoing first-line chemotherapy after diagnosis of lymphoma have considerable DNA damage in their peripheral blood lymphocytes, using sister chromatid exchange (SCE) frequency as a sensitive indicator. Different drug regimens produce different patterns of changes in SCE frequency. These may be related to their potential to induce second malignancies.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Missense Mutation in the Chlamydomonas Chloroplast Gene that Encodes the Rubisco Large Subunit.

The 69-12Q mutant of Chlamydomonas reinhardtii lacks ribulose-1,5-bisphosphate carboxylase activity, but retains holoenzyme protein. It results from a mutation in the chloroplast large-subunit gene that causes an isoleucine-for-threonine substitution at amino-acid residue 173. Considering that lysine-175 is involved in catalysis, it appears that mutations cluster at the active site.

Journal Article↗
PubMed1988

Chronic recurrent multifocal osteomyelitis.

Chronic recurrent multifocal osteomyelitis is a recognized condition that usually affects children and adolescents. It generally has a self-limited course, causing significant symptoms but leaving few, if any, residual changes in most cases. The authors undertook a retrospective review of the radiographs and medical records of 11 patients with chronic recurrent multifocal osteomyelitis. They found that not all patients have complete resolution of disease, and a small minority may be left with residual bone changes. Chronic recurrent multifocal osteomyelitis was originally reported in Switzerland; most reported cases are from Europe and Scandinavia. The disease is being recognized with increasing frequency in North America.

Child↗
PubMed1988

Prostaglandin E2 is an inhibitor of adenylate cyclase in rabbit proximal tubule.

Prostaglandin E1 and E2 (PGE) antagonize the phosphaturic effect of parathyroid hormone (PTH), but do not alter the phosphaturia evoked by adenosine 3',5'-cyclic monophosphate (cAMP) analogues. These findings support the idea that PGE interfere with activation of adenylate cyclase in the renal proximal tubule. We tested this hypothesis in the rabbit renal proximal straight tubule (PST). In the PST, adenylate cyclase was activated by PTH (Km = 10(-9) M PTH), but not by PGE2, which attenuated the activation of adenylate cyclase by PTH. The inhibition by PGE2 of PTH action was prevented by pertussis toxin, which deactivates the regulatory aggregate, Ni. In the PST, PGE2 also attenuated the activation of adenylate cyclase by cholera toxin. The inhibitory effect of PGE2 was selective; PGE2 did not inhibit activation of adenylate cyclase in glomeruli, but it inhibited the enzyme in proximal convoluted tubules (PCT) and PST. We conclude that PGE2 inhibits adenylate cyclase in rabbit proximal tubule. We propose that this action may, in part, regulate transport function in vivo.

Adenylate Cyclase Toxin↗
PubMed1988

Feline plague in New Mexico: risk factors and transmission to humans.

The epidemiologic features of 60 cases of feline plague from 1977-1985 in New Mexico are reviewed. The most frequent clinical presentation was lethargy, anorexia, fever, and enlarged lymph nodes or abscesses. A history of hunting rodents was reported in 75 per cent of all cases. Five human plague cases were associated with five feline cases. Recommendations are presented for prevention of plague infection and transmission to humans, including restraining cats from roaming and hunting by neutering and keeping them indoors, treating them for fleas, and seeking medical care for febrile illnesses, especially when accompanied by enlarged lymph nodes.

Animals↗