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Biomedical subjects

L M Hall

Publications and source records attributed to L M Hall.

At least 145 records · Page 8Linked to original sources
PubMed1979

Unsymmetrical C-substituted ethylenediamine platinum coordination complexes: synthesis and activity against mouse leukemia L1210.

A series of new unsymmetrical C-substituted ethylenediamines was prepared. The substituents included branched chain alkyl, cycloalkyl, and phenyl groups. Twenty-eight new platinum compounds were prepared from these diamines and were tested for activity against leukemia L1210. The cycloalkyl substituted ethylenediamines produced especially active compounds. The phenyl-substituted analogs were generally low in activity. The activity of the complexes was compared to aqueous solubility, organic solubility, and amphipathic character. There was good indication that antitumor activity increased as aqueous solubility and hydrophilic character of the molecules increased.

Animals↗
PubMed1979

Distribution of binding sites for 125I-labeled alpha-bungarotoxin in normal and deafferented antennal lobes of Manduca sexta.

125I-Labeled alpha-bungarotoxin has been used to determine the distribution of putative acetylcholine receptors in normal and chronically deafferented antennal lobes in the brain of the moth Manduca sexta. Toxin-binding sites are confined to synaptic regions in deafferented lobes. These findings suggest that receptors can develop in the insect central nervous system independently of normal synaptic influences.

Afferent Pathways↗
PubMed1976

Correlation of guanosine triphosphate cyclohydrolase activity and the synthesis of pterins in Drosophila melanogaster.

The enzyme guanosine triphosphate cyclohydrolase (GTP cyclohydrolase), which in bacteria is known to be the first enzyme in the biosynthetic pathway for the synthesis of pteridines, has been discovered in extracts of Drosophila melanogaster. Most of the enzyme (80%) is located in the head of the adult fly. An analysis of enzyme activity during development in Drosophila has revealed the presence of a relatively small peak of activity at pupariation and a much larger peak that appears at about the time of eclosion. Enzyme activity declines radidly as the fly ages. Analysis for the production of the typical pteridine pigments of Drosophila have indicated that the small peak of GTP cyclohydrolase activity evident at pupariation coincides with the appearance of isoxanthopterin, sepiapterin, and pterin, and the larger peak at eclosion roughly corresponds to the accumulation of drospterin as well as to the appearence in larger amounts of pterin and sepiaterin. These observations strongly suggest that in Drosophila, like bacteria, GTP cyclohydrolase is involved in the biosynthesis of pteridines. Analyses of a variety of zeste mutants of Drosophila melanogaster have shown that these mutants all contain GTP cyclohydrolase equal approximately to the amount found in the wild-type fly. These observations do not support the suggestions made by Rasmusson et al. (1973) that zeste is the strucural locus for GTP cyclohydrolase.

Aminohydrolases↗
PubMed1975

Serum chemistry templates of disease in liver, pancreas, and gallbladder.

On routine hospital admission, 23,714 patients received a 28-test serum metabolic profile. The 33 most common diseases (4,132 patients) of liver, pancreas, and gallbladder (LPG) had unique chemical templates averaging 15 significant serum deviations. Each LPG disease differed from all others by elevations of both leucine-aminopeptidase (LAP) and alkaline phosphatase (AP) levels. LAP level was low or normal and serum glutamic oxaloacetic transaminase (SGOT) and AP levels were elevated in 43 non-LPG diseases. Patients with acute and chronic pancreatitis had elevated amylase levels. The four nonmalignant diseases of the gallbladder were associated with normal levels of amylase and lactic dehydrogenase (LDH); except for silent cholelithiasis, each showed elevated total bilirubin (BIL) levels. Patients with solitary or scattered lesions of the liver had normal bilirubin levels (2,115 patients), and those with diffuse interstitial or parencymal disease had elevated BIL levels. Cancer patients had elevated LDH and alpha1 globulin (A1G) levels, but low albumin levels. The importance of comprehensive liver profiles in the treatment of psychoses is emphasized by significant liver damage in a number of these patients. A1G was normal and LDH was elevated in patients having mononucleosis, hepatitis, lupus erythematosus, alcoholism, and alcoholic cirrhosis.

Alkaline Phosphatase↗
PubMedDate not supplied

Two types of mutants affecting voltage-sensitive sodium channels in Drosophila melanogaster.

Voltage-sensitive sodium channels have a key role in the genesis of propagated action potentials. Mutations that affect these channels might be used like specific pharmacological agents in studies of channel structure and regulation. We have found that mutations which cause a reversible, temperature-induced paralysis in the fruit fly Drosophila melanogaster often affect the voltage-sensitive sodium channel. Using 3H-saxitoxin binding to membrane preparations, we have now identified two types of presumptive sodium channel mutants. One mutation, seizurets-2 (seits-2), appears to alter saxitoxin-binding sites structurally. The second, no-action-potential (napts) (refs 5, 6), reduces the number of saxitoxin-binding sites, but appears not to alter the receptor structure.

Animals↗
PubMedDate not supplied

QSAR modeling based on structure-information for properties of interest in human health.

The development of QSAR models based on topological structure description is presented for problems in human health. These models are based on the structure-information approach to quantitative biological modeling and prediction, in contrast to the mechanism-based approach. The structure-information approach is outlined, starting with basic structure information developed from the chemical graph (connection table). Information explicit in the connection table (element identity and skeletal connections) leads to significant (implicit) structure information that is useful for establishing sound models of a wide range of properties of interest in drug design. Valence state definition leads to relationships for valence state electronegativity and atom/group molar volume. Based on these important aspects of molecules, together with skeletal branching patterns, both the electrotopological state (E-state) and molecular connectivity (chi indices) structure descriptors are developed and described. A summary of four QSAR models indicates the wide range of applicability of these structure descriptors and the predictive quality of QSAR models based on them: aqueous solubility (5535 chemically diverse compounds, 938 in external validation), percent oral absorption (%OA, 417 therapeutic drugs, 195 drugs in external validation testing), AMES mutagenicity (2963 compounds including 290 therapeutic drugs, 400 in external validation), fish toxicity (92 substituted phenols, anilines and substituted aromatics). These models are established independent of explicit three-dimensional (3-D) structure information and are directly interpretable in terms of the implicit structure information useful to the drug design process.

Animals↗
PubMedDate not supplied

Developing a nursing management practice atlas: Part 1, Methodological approaches to ensure data consistency.

Challenges associated with the use of secondary data sources for benchmarking in nursing administration research are identified. A methodological approach for ensuring data consistency is presented in part one of this two-part series. Part two (September 2000) will provide an analysis of the nursing management data, based on a set of nursing and financial resource benchmarking variables identified by the senior nurse executives of these sites. Initial findings show evidence of data consistency across similar hospitals.

Abstracting and Indexing↗
PubMedDate not supplied

Redesigning nursing work in long-term care environments.

The authors present a highly statistically oriented argument for examining work attitudes and activities among three groups of caregivers [RNs, RPNs, and HCAs] working in long-term care. The investigators used both work sampling, written surveys, and interviews with a sample of 46 caregivers in a large university-affiliated LTC facility in Toronto, Canada. While RNs stated their strong affinity for direct patient care activities, they perform the lowest percentage of direct care, chiefly due to their accountability for planning and coordinating the care provided by others. The HCAs who provided the bulk of direct patient care "valued it the least," apparently finding little gratification with this aspect of their role. This study suggests that there is a need to examine and clarify work roles and perceptions for all caregivers as part of any work redesign process. A higher level of RN involvement in direct patient care activities, along with "attention to enhancing the importance" of these activities for staff employed in the HCA role, could be beneficial.

Adult↗
PubMedDate not supplied

Coordination complexes of platinum as antitumor agents.

Rosenberg and VanCamp first reported the bacteriostatic and antitumor properties of certain platinum coordination compounds. This pioneering work has led to the synthesis and testing of a large number of related platinum products and the clinical use of cis-dichlorodiammineplatinum (II). This drug has proven very efficacious against a wide variety of mouse tumors when employed as the sole chemotherapeutic agent and has also been combined successfully with other antitumor agents, such as cyclophosphamide and cytosine arabinsoide. Unfortunately, cis-dichlorodiammineplatinum (II) has a low therapeutic index with renal toxicity being the principal limitation of its use. This has prompted the synthesis and testing of many related platinum compounds, of which cis-dichlorobiscyclopentylamine-platinum (II) and the "platinum blues" appear most promising. Experience in the synthesis, purification, and testing of such products will be discussed together with identification of outstanding unsolved problems in this area.

Animals↗