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Biomedical subjects

M Gall

Publications and source records attributed to M Gall.

15 recordsLinked to original sources
PubMed2005

Water quality monitoring: a combined approach to investigate gradients of change in the Great Barrier Reef, Australia.

For the managers of a region as large as the Great Barrier Reef, it is a challenge to develop a cost effective monitoring program, with appropriate temporal and spatial resolution to detect changes in water quality. The current study compares water quality data (phytoplankton abundance and water clarity) from remote sensing with field sampling (continuous underway profiles of water quality and fixed site sampling) at different spatial scales in the Great Barrier Reef north of Mackay (20 degrees S). Five transects (20-30 km long) were conducted from clean oceanic water to the turbid waters adjacent to the mainland. The different data sources demonstrated high correlations when compared on a similar spatial scale (18 fixed sites). However, each data source also contributed unique information that could not be obtained by the other techniques. A combination of remote sensing, underway sampling and fixed stations will deliver the best spatial and temporal monitoring of water quality in the Great Barrier Reef.

Animals↗
PubMed2000

A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization.

Changes in iron supply to oceanic plankton are thought to have a significant effect on concentrations of atmospheric carbon dioxide by altering rates of carbon sequestration, a theory known as the 'iron hypothesis'. For this reason, it is important to understand the response of pelagic biota to increased iron supply. Here we report the results of a mesoscale iron fertilization experiment in the polar Southern Ocean, where the potential to sequester iron-elevated algal carbon is probably greatest. Increased iron supply led to elevated phytoplankton biomass and rates of photosynthesis in surface waters, causing a large drawdown of carbon dioxide and macronutrients, and elevated dimethyl sulphide levels after 13 days. This drawdown was mostly due to the proliferation of diatom stocks. But downward export of biogenic carbon was not increased. Moreover, satellite observations of this massive bloom 30 days later, suggest that a sufficient proportion of the added iron was retained in surface waters. Our findings demonstrate that iron supply controls phytoplankton growth and community composition during summer in these polar Southern Ocean waters, but the fate of algal carbon remains unknown and depends on the interplay between the processes controlling export, remineralisation and timescales of water mass subduction.

Atmosphere↗
PubMed1994

Implementing structure and control over unofficial inventories in a multispecialty group practice.

Materiel managers have been in control of most aspects of the supply chain except for the inventories of the end users, which account for 70 percent of the inventory supply dollars. When the Materials Manager at Lexington Clinic in Lexington, Kentucky, was approached by the Clinic's Chief Executive Officer to implement cost containment measures, the Materials Manager seized the opportunity to implement a six-step program aimed at controlling those supply dollars. Through requisition training, enforcing approval levels, limiting the number of requisitioners, and establishing par levels on floor inventories, the clinic's "unofficial" inventory supply dollars were reduced by 7 percent in the first 12 departments where the par levels were established. The program was hailed as a tremendous success and a positive experience for everyone, from nurses to warehouse clerks.

Cost Savings↗
PubMed1991

Molecular modeling of 5-HT3 receptor ligands.

Ligands of various chemical classes (e.g., indoles, indazoles, benzamides, carbazoles, and quinolines) have demonstrated high affinity for the 5-HT3 receptor in radiolabeled ligand-binding studies, and have shown 5-HT3 receptor antagonistic activity in functional assays which utilize the excitatory effects of 5-HT on enteric neurons and autonomic afferents. Several 5-HT3 antagonists are currently being evaluated for potential use in the treatment of migraine, schizophrenia, and anxiety, and a few have already demonstrated high efficacy as antiemetics in cancer chemotherapy. The purpose of this presentation is to highlight the significant structure-affinity relationships (SAFIR) and common geometrical features among 5-HT3 receptor ligands, and to describe the three-dimensional pharmacophore for the 5-HT3 recognition site derived from computational techniques. The chemical template containing the recognition elements (functional groups) for the 5-HT3 receptor are: an aromatic or heteroaromatic ring system, a coplanar carbonyl group, and a nitrogen center, interrelated by well-defined distances. Two "binding shapes" or "active shapes" for 5-HT3 ligands have been identified from detailed conformational analyses.

Animals↗
PubMed1991

Pregnancy-induced changes in the maximal physiological responses during swimming.

The effect of pregnancy on peak O2 uptake (VO2 peak) during tethered swimming was evaluated in 10 women during their 25th and 35th wk of pregnancy, as well as 9-11 wk postpartum. The swim results were compared with cycle ergometry results obtained at similar times. The results indicated that exercise-induced maximal heart rates remained the same and were similar for the swim and cycle trials, approximately 184 +/- 4 beats/min. Cycling VO2 peak was not affected by pregnancy, averaging 1.94 +/- 0.11 l/min. Postpartum swim VO2 peak was similar to the cycle results; however, during pregnancy it was significantly lower than cycling VO2 peak (P less than 0.05; postpartum, 1.78 +/- 0.14 l/min; 25th wk, 1.64 +/- 0.12; 35th wk, 1.48 +/- 0.11). Hemoglobin concentrations and hematocrits were lower during pregnancy; however, changes in plasma volume (based on hematocrit and hemoglobin) were found to be significantly greater during cycling than during swimming and also greater during pregnancy for both modes of exercise. It was concluded that, unlike cycling, the VO2 peak of pregnant women during swimming is reduced. This reduction in VO2 peak was associated with a decreased peak ventilation (r = 0.864) but was not correlated to exercise-induced hemoconcentration (r = -0.29). Furthermore, pregnancy results in a greater-than-normal exercise-induced hemoconcentration, which may be related to pregnancy-induced changes in capillary dynamics.

Adult↗
PubMed1990

Fetal umbilical artery Doppler response to graded maternal aerobic exercise and subsequent maternal mean arterial blood pressure: predictive value for pregnancy-induced hypertension.

Predictive tests for the identification of women at high risk of the development of preeclampsia are critical to allow the most appropriate preventive measures. Preeclampsia is a vasospastic condition of pregnancy characterized by early and enhanced vascular reactivity to endogenous pressor agents. Exercise tolerance testing with cycle ergometry to induce hemodynamic response measured with duplex Doppler A/B ratio of the umbilical artery could unmask latent vascular pressor hypersensitivity. Our prospective cohort study was designed to test the efficacy of the American College of Obstetricians and Gynecologists exercise in pregnancy guidelines for the low-risk athletic, physically active, or sedentary patient. The pattern of fetal response to material exercise testing at 28 weeks' gestation was compared with subsequent maternal mean arterial blood pressure and the development of pregnancy-induced hypertension and preeclampsia. Doppler A/B ratio during the recovery period was assessed as below baseline (18) or elevated above resting baseline values (12). Third-trimester blood pressure pattern was assessed to be elevated in 11 patients, 10 of whom had elevated recovery A/B ratios. The Fisher exact test results were (p = 0.00002) positive predictive value, 83%; negative predictive value, 94%; sensitivity, 91%; and specificity, 89%. Preeclampsia developed in four patients; all had elevated recovery A/B ratios. Fisher exact test results were (p = 0.01806) positive predictive value, 33%; negative predictive value, 100%; sensitivity, 100%; and specificity, 69%.

Blood Pressure↗
PubMed1988

Arylformamidines with antinociceptive properties.

A series of formamidines structurally related to clonidine were synthesized and investigated as potential nonopiate analgesics. Several of these compounds showed potent analgesic activity (ED50 on HCl writhing less than 1.0 mg/kg) with low potential for hypotensive effects. A qualitative description of the structure-activity relationship of this series reveals that the 2,4- and 2,6-dimethylphenyl compounds are more potent analgesics than are the corresponding dichlorophenyl compounds.

Analgesia↗
PubMed1988

Health counseling for adolescents: what they want, what they get, and who gives it.

To determine the extent of health counseling received by college freshmen from their primary health care providers, 362 students answered questions regarding 15 health topics. Internists provided more counseling than pediatricians and family/general practitioners about smoking and alcohol use, more than pediatricians about drug use and heart disease prevention, and more than family/general practitioners about weight control and nutrition. Pediatricians exceeded family/general practitioners in counseling about weight control and nutrition but did not exceed internists in any areas. For 11 of 15 topics, more than 75% of students reported receiving no counseling. Women were counseled for stress and contraception more frequently than men. Overall, topics most often discussed by physicians were exercise, nutrition, and breast self-examination. The topics most frequently requested by students were exercise, stress (women), depression, weight control (women) and sexually transmitted diseases (men). These data suggest that adolescents receive little health counseling from personal physicians, especially regarding topics leading to great morbidity and mortality for this age group. Pediatricians, especially, must increase the extent of counseling if they are to meet the American Academy of Pediatrics' goal of providing care to adolescents and young adults.

Adolescent↗
PubMed1978

Novel anxiolytic agents derived from alpha-amino-alpha-phenyl-o-tolyl-4H-triazoles and -imidazoles.

Several new alpha-amino-alpha-phenyl-o-tolytriazoles and -imidazoles have been prepared in one step by means of a novel reductive rearrangement of the corresponding benzodiazepines with hydrazine hydrate. These new triazoles were found to have moderate sedative and muscle relaxing activity in mice (i.e., these compounds depressed the traction and dish reflexes at higher doses than did diazepam) but were very potent antagonists of the clonic convulsions induced in mice by the administration of pentylenetetrazole. Furthermore, they antagonized the lethality induced by thiosemicarbazide. While these new compounds were very active in mice, most were inactive in rats. These results are discussed with reference to the metabolism of compound 13.

Animals↗
PubMed1978

Pharmacology of some metabolites of triazolam, alprazolam, and diazepam prepared by a simple, one-step oxidation of benzodiazepines.

A simple, one-step chemical oxidation of triazolam (7) to its 4-hydroxy analogue, 7a, has been developed and applied to other triazolo- and imidazobenzodiazepines. The reaction may be used to convert diazepam to temazepam. 4-Hydroxytriazolo[4,3-a][1,4]benzodiazepines have low central nervous system sedative and anticonvulsant activity in sharp contrast to metabolites of diazepam which remain active. While 10, an alpha-hydroxy metabolite of triazolam, retains much of the activity of 7, 10a, and alpha,4-dihydroxy metabolite of triazolam, is 250 times less potent than 7 on the nicotine-antagonism assay and over 300 times less potent on the traction assay.

Animals↗
PubMed1978

[On the use of computer tomography (CT) in clinical psychiatry (author's transl)].

220 hospitalized psychiatric patients were examined by computerized tomography (CT) mostly to exclude organic brain dammage. A third of the material proved to be within the normal range, when also slight cortical and subcortical atrophies are considered to be abnormal. Pronounced cerebral atrophy was found in 26.8% of the cases, 5% revealed other significant lesions. CT is a very promissing help in distinguishing vascular from purely degenerative processes. Chronic alcoholism showed an amount of 67% cortical atrophies of all degrees. Endogenic psychoses on the other side failed to demonstrate characteristic results. Many of possible unspecific pathogenetic factors seem to play an important role in this and other disease processes. CT as an almost non-invasive method may be repeated in dubious cases.

Adult↗
PubMed1976

Synthesis and pharmacology of novel anxiolytic agents derived from 2-[(dialkylamino)methyl-4H-triazol-4-yl] benzophenones and related heterocyclic benzophenones.

A series of novel [(dialkylamino)methyl-4H-1,2,4-triazol-4-yl]benzophenones and related compounds has been prepared via total synthesis from substituted aminodiphenylmethanes or by hydrolysis and subsequent methylation of triazolobenzodiazepines. These new triazole compounds were found to have potent sedative and muscle relaxing activity in mice (i.e., these compounds depressed the traction and dish reflexes). In addition, the title compounds antagonized the clonic convulsions induced in mice by the administration of pentylenetratrazole (Metrazol, 85 mg/kg), with ED50's varying from 2.0 to 23.0 mg/kg, and the lethality induced by thiosemicarbazide, with ED50's varying from 0.02 to 9.0 mg/kg. In several biological tests, the potency of seven new benzophenone derivatives approached or exceed that of diazepam (35a) or its glycylaminobenzophenone analogue 36.

Animals↗
PubMed1976

Conversion of N-alkylaminobenzophenones to benzodiazepines in vivo.

The results of this study suggest that 5-chloro-2-[3-methyl-5-(dimethylamino)methyltriazol-4-yl]benzophenone can undergo N-dealkylation and ring closure in vivo to form the corresponding benzodiazepine. The in vivo conversion was found to occur in mice, rats, and monkeys. A variety of substituted aminobenzophenone compounds were also able to undergo these conversions. The conversions to benzodiazepines were confirmed by a comparison of retention times on a gas chromatograph as well as through the use of a GC-mass spectrometer. The results obtained did not prove that the N-alkylaminobenzophenones were devoid of activity, but they do suggest that their observed pharmacological activity may be due to the formation of the corresponding benzodiazepines.

Animals↗