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Biomedical subjects

E Heath

Publications and source records attributed to E Heath.

At least 19 recordsLinked to original sources
PubMed2006

Trace-level determination of pharmaceutical residues by LC-MS/MS in natural and treated waters. A pilot-survey study.

A pilot-survey study was performed by collecting samples (influent and effluent wastewaters, rivers and tap waters) from different locations in Europe (Spain, Belgium, Germany and Slovenia). A solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry method was applied for the determination of pharmaceuticals (ibuprofen, naproxen, ketoprofen, diclofenac and clofibric acid). Method detection limits and method quantification limits were at the parts-per-trillion level (7.5-75 ng/L). The recovery rates of the SPE from deionized water and effluent wastewater samples spiked at 100- and 1,000-ng/L levels ranged from 87 to 95%. Identification criteria in compliance with the EU regulation for confirmatory methods of organic residues were applied. A detailed study of signal suppression evaluation for analysis of pharmaceutical residues in effluent wastewaters is presented.

Chromatography, Liquid↗
PubMed2005

IMRT head and neck treatment planning with a commercially available Monte Carlo based planning system.

The PEREGRINE Monte Carlo dose-calculation system (North American Scientific, Cranberry Township, PA) is the first commercially available Monte Carlo dose-calculation code intended specifically for intensity modulated radiotherapy (IMRT) treatment planning and quality assurance. In order to assess the impact of Monte Carlo based dose calculations for IMRT clinical cases, dose distributions for 11 head and neck patients were evaluated using both PEREGRINE and the CORVUS (North American Scientific, Cranberry Township, PA) finite size pencil beam (FSPB) algorithm with equivalent path-length (EPL) inhomogeneity correction. For the target volumes, PEREGRINE calculations predict, on average, a less than 2% difference in the calculated mean and maximum doses to the gross tumour volume (GTV) and clinical target volume (CTV). An average 16% +/- 4% and 12% +/- 2% reduction in the volume covered by the prescription isodose line was observed for the GTV and CTV, respectively. Overall, no significant differences were noted in the doses to the mandible and spinal cord. For the parotid glands, PEREGRINE predicted a 6% +/- 1% increase in the volume of tissue receiving a dose greater than 25 Gy and an increase of 4% +/- 1% in the mean dose. Similar results were noted for the brainstem where PEREGRINE predicted a 6% +/- 2% increase in the mean dose. The observed differences between the PEREGRINE and CORVUS calculated dose distributions are attributed to secondary electron fluence perturbations, which are not modelled by the EPL correction, issues of organ outlining, particularly in the vicinity of air cavities, and differences in dose reporting (dose to water versus dose to tissue type).

Algorithms↗
PubMed2000

Endosonographic assessment of multimodality therapy predicts survival of esophageal carcinoma patients.

BACKGROUND: Standard endosonographic (EUS) staging criteria are unreliable for staging esophageal carcinoma after neoadjuvant therapy; however, measurement of tumor size reduction can identify patients who have achieved a pathologic response. In the current study the authors prospectively compared survival between patients classified as responders and those classified as nonresponders by EUS. METHODS: The maximal transverse cross-sectional area of the tumor was measured before and after neoadjuvant therapy in patients who were candidates for multimodality treatment. Response was defined as a > or = 50% reduction in tumor area. RESULTS: A total of 59 patients at 2 centers were followed for a median of 19 months. EUS assessed response in 34 patients (58%). Overall, responders had a median survival of 17.6 months compared with 14.5 months for nonresponders (P < 0.005). Survival was significantly longer in responders compared with nonresponders in the patient subgroup who underwent surgical resection (19.7 months vs. 14.6 months; P < 0. 005), the patient subgroup with adenocarcinoma (21.4 months vs. 10.8 months; P < 0.005), and the patient subgroup initially classified as having T3N1 disease (17.6 months vs. 14.1 months; P < 0.05). Survival was not found to differ significantly between responders and nonresponders in the subgroup of patients with squamous cell carcinoma. EUS response was the only clinical variable that was associated with survival time in a multivariate analysis (relative hazard = 0.27; P < 0.005). CONCLUSIONS: Patients with esophageal carcinoma who respond to neoadjuvant treatment as identified by EUS measurement of reduction in tumor size have a significantly better prognosis than nonresponders.

Adenocarcinoma↗
PubMed1997

Assessment of health risks due to hazardous air pollutant emissions from electric utilities.

Hazardous air pollutant (HAP) emissions from electric utilities were evaluated. Cancer risks, as well as noncancer effects, due to inhalation exposure were assessed for 67 HAPs. Also, cancer risks due to multipathway exposure to radionuclide emissions were assessed. In addition, an assessment of the fate of mercury (Hg) through various environmental media was included. Results suggest arsenic, chromium, and nickel are the HAPs that present the highest cancer risk due to inhalation exposure. For noncancer effects due to inhalation exposure, hydrogen chloride appears to present the greatest potential concern. The risks due to multipathway exposure to radionuclides are estimated to be of similar magnitude to the risks posed by inhalation of arsenic and nickel. Mercury is of potential concern for multipathway exposures because it persists in the environmental and bioaccumulates in the aquatic food web. The study suggests there is a plausible link between Hg emissions from utilities and the Hg found in soil, water, and freshwater fish.

Air Pollutants↗
PubMed1996

Relatives' perceptions of role change, social support and stress after traumatic brain injury.

There is general agreement between researchers and clinicians alike that relatives of people with head injuries experience heightened stress as a result of the injury and its consequences. In the present study a single structured interview, including both verbally administered and written response questionnaires, was completed by 18 parents and 11 partners. Measures included the Daily Hassles and Uplifts Scale, the Arizona Social Support Interview Schedule and questions regarding role change and health problems. The combined parents and partners group indicated that they experienced moderate levels of stress and role change. A relatively small proportion of participants reported experiencing health problems. Partners indicated a slightly higher degree of stress and a greater degree of role change than parents, and a larger proportion of partners indicated the presence of health problems. Qualitative differences between the two groups were found in terms of sources of stress. There was little quantitative or qualitative difference between the two groups in sources, utilization of and satisfaction with social support. Positive correlations were found between stress and role change and stress and health problems.

Activities of Daily Living↗
PubMed1992

Are children who steal different from those who are aggressive?

Data on 2181 children referred to a child psychiatry service were analyzed to determine if there were specific correlates for aggressive behavior and for stealing behavior. Compared with stealers, aggressive children tended to be younger and more immature males, and to come from stressed families with a history of mental illness. These findings support the notion that there are biological and reactive components to aggression.

Adolescent↗
PubMed1988

The structure of the epididymis of the giant rat (Cricetomys gambianus, Waterhouse): histological, histochemical and microstereological studies.

The structure of the ductus epididymidis of the African giant rat (Cricetomys gambianus, Waterhouse) was studied by means of histological (paraffin and plastic-embedded tissues) and histochemical techniques. Five distinct zones (I-V) were detected along the epididymal duct on the basis of epithelial height and cytological composition and structure. The so-called apical cells, which have been observed in some species of animals, were not seen in the initial segment of the duct. Clear or light cells were present in the epithelium of the terminal segment, thus making the giant rat the third species in which this cell has been found, after the laboratory rat and the hamster. A large number of intra-epithelial lymphocytes and macrophage-like cells was commonly observed in the epithelium throughout the duct; the latter were strongly PAS-positive while the former tended to increase in number caudally. A microstereological study of the epididymis showed that Zones I (initial segment) and II contained a significantly (P less than 0.001) higher proportion of epithelium and a relatively greater (P less than 0.001) proportion of blood vessels in the interductal connective tissue than the more caudal segments of the epididymis which possessed a significantly (P less than 0.01) higher proportion of interductal connective tissue.

Acid Phosphatase↗
PubMed1988

Effects of prostaglandin F2 alpha on degranulation of bovine luteal cells on days 4 and 12 of the estrous cycle.

Corpora lutea were collected from 18 beef heifers on day 4 or 12 of the estrous cycle, 1 hour after prostaglandin (PG) F2 alpha or saline (control) treatment. Five heifers also were treated with PGF2 alpha on day 4, but their corpora lutea were not collected until day 12. The relative percentage of cytoplasm occupied by granules decreased only in large luteal cells (LLC) in heifers given PGF2 alpha on day 12, compared with the percentage in controls. Small luteal cells (SLC) were not as affected. The luteal concentration of progesterone was similarly decreased only in heifers given PGF2 alpha on day 12. Treatment of heifers with PGF2 alpha on day 4 had no marked effect on progesterone values or on the relative percentage of cytoplasm occupied by granules in LLC or SLC. Seemingly, LLC were more responsive to PGF2 alpha than were SLC, and PGF2 alpha treatment of beef heifers at day 4 did not markedly impair luteal function.

Animals↗
PubMed1986

Disposition of the manchette and related events in the feline spermatid.

The manchette is a transient microtubular organelle previously considered to "disappear" prior to formation of the definitive midpiece of the spermatozoon. Goodrowe and Heath (1984) have suggested, however, that in stallions the final disposition of the microtubules of the manchette is into the residual cytoplasm. In the present study, spermiogenesis was examined by transmission electron microscopy of testicular samples from eight cats. Feline spermatids also had a manchette of cylindrical shape, largely located in a cytoplasmic collar peripheral to the presumptive midpiece. The parallel microtubules of the manchette were interconnected by arms. Some of these arms were still present after rupture of the manchette cylinder and movement of the microtubules into the residual cytoplasm. On displacement of the manchette microtubules, mitochondria, spherical in shape and peripherally located, moved centrally to elongate and encircle the flagellum to form the definitive midpiece.

Animals↗
PubMed1985

Ultrastructural categorization of human sperm cryopreserved in glycerol and in TESTCY.

The motility of human sperm after thawing and the ultrastructural integrity of their acrosomal region was evaluated in 5 semen donors after utilizing 2 cyproprotective extenders--glycerol and TESTCY. Sperm motility in the fresh control semen fraction (65.5% +/- 6.1) was significantly (P less than 0.05) better than the immediate post-thaw motility in both cyprotected fractions (38.8% +/- 2.0 for glycerol and 31.0% +/- 2.9 for TESTCY), and there was no significant difference between the two cyprotective treatments. The overall % of normal intact sperm heads was significantly less than in controls (P less than 0.05) following cypropreservation in glycerol, but values for sperm stored in TESTCY were not significantly different from controls or glycerol. However, when expressed as % change from controls values, sperm preservation was significantly better (P less than 0.05) in TESTCY than in glycerol. TESTCY is considered a better cryoprotective agent for human sperm.

Buffers↗
PubMed1985

Microtubular mass defect of spermatozoa in the stallion.

A microtubular mass (MM) defect was found in the spermatozoa of 7 Standardbred stallions; 3 stallions were sons of the same sire. Two of these 3 stallions and 2 other stallions (for a total of 4 out of the 7 stallions) were considered subfertile when the defect was first observed. Fertility improved with time, either during the first breeding season or when a given stallion was used less frequently; however, the MM defect persisted, consisting of tortuous arrays of small abnormal microtubules visible only by transmission electron microscopy. The MM probably contained the protein tubulin as indicated by immunofluorescence. Microtubules of the MM were different from normal microtubules in being highly coiled, rather than straight, without interconnecting bridges or arms and had a 20% smaller cross-sectional diameter than did normal microtubules. Synthesis of the MM may occur near areas of the nuclear membranes normally associated with the manchette of the developing spermatid.

Animals↗
PubMed1984

Disposition of the manchette in the normal equine spermatid.

Bielanski and Kaczmarski (1979) reported the presence of microtubules in the neck region of mature stallion spermatozoa. It was hypothesized that these microtubules are derived from the manchette (a microtubular organelle present during spermiogenesis). In order to test this hypothesis, testes from 15 mature stallions were collected, perfused with 2% phosphate-buffered glutaraldehyde, and prepared for transmission electron microscopy. Spermatozoa from the caudae epididymides of each stallion were prepared in a similar manner. Spermiogenesis was observed in general, and the presence of a microtubular manchette was established in this species, juxtapositioned posterior to the nuclear ring and extending distally into the cytoplasmic collar which surrounds the prospective midpiece. Interlocking arms between the microtubules of the manchette were observed in transverse sections at all levels within the cytoplasmic collar before, during, and after caudal migration of the nuclear ring. Consequent to caudal migration of the nuclear ring and the annulus, as well as adluminal movement of the spermatid, the cytoplasmic collar was transformed into the residual cytoplasm. Within the residual cytoplasm, the manchette remained as a microtubular organelle which undergoes degeneration. The mature spermatozoa from the caudae epididymides of these stallions lacked the microtubules reported by Bielanski and Kaczmarski. The occurrence of such microtubules in the neck region of stallion spermatozoa is probably an abnormality.

Animals↗
PubMed1983

Effects of prostaglandins on the bovine corpus luteum: granules, lipid inclusions and progesterone secretion.

Corpora lutea collected at 15, 30 and 60 min after prostaglandin F2 alpha (PGF2 alpha) treatment were compared to control corpora lutea at 60 min after saline treatment. There were decreases (P less than 0.05) in the relative percentages of cytoplasm occupied by granules in large luteal cells (LLC) by 30 min and in small luteal cells (SLC) by 60 min. Differences were not observed among the groups for lipid inclusions. Luteal progesterone was decreased at all post-PGF2 alpha treatment times when compared to 60-min controls (P less than 0.05). PGF2 alpha was then compared with prostaglandin F1 alpha (PGF1 alpha), prostaglandin E1 (PGE1), and 17-phenyl-18,19,20-trinor-prostaglandin F2 alpha (17-phenyl-PGF2 alpha) in 60-min trials with plasma progesterone and luteinizing hormone (LH) determined every 5 min. LH was not affected by these treatments. Like PGF2 alpha, 17-phenyl-PGF2 alpha induced a greater loss of granules from LLC then SLC. 17-phenyl-PGF2 alpha also induced an increase in the lipid content of LLC. Treatments with PGF2 alpha and 17-phenyl-PGF2 alpha were associated with decreased concentrations of luteal progesterone but PGF1 alpha and PGE1 were without effect on this variable. In contrast to PGF1 alpha, PGE1 increased both luteal progesterone and the area occupied by cytoplasmic granules. The latter effect was greater in LLC than SLC.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗