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Biomedical subjects

R Day

Publications and source records attributed to R Day.

At least 235 records · Page 13Linked to original sources
PubMed1987

Carbon fiber reinforced plastic (CFRP) plates versus stainless steel dynamic compression plates in the treatment of fractures of the tibiae in dogs.

In a series of 14 dogs, fractures of both tibiae were caused by a "bone-breaker" designed in the authors' department and observed to produce a consistent and realistic canine fracture. One tibia was plated with a carbon fiber reinforced plastic (CFRP) plate and the other with a dynamic compression (DC) plate. Roentgenographic examination demonstrated healing of the CFRP-plated tibiae with abundant callus, and almost total remodeling of the fracture callus between ten and 20 weeks. Biomechanical testing by three-point bending revealed little difference between the strength of union of the fractures at 12-16 weeks. At 20 weeks, although the numbers were too small for statistical confirmation, the CFRP-plated tibiae were consistently stronger than the DC-plated tibiae.

Animals↗
PubMed1986

Bombesin-like immunoreactivity in bovine adrenal medulla.

The presence of immunoreactive (ir)-bombesin in bovine adrenal medulla, isolated adrenal chromaffin cells and subcellular fractions of the adrenal medulla was demonstrated using a specific antibody to the synthetic peptide. High levels of ir-bombesin were detected in acid (HCl) extracts of the adrenal tissue (27 pmol/g) and isolated cells (0.35 pmol per 10(6) cells). Subpopulations of adrenal chromaffin cells were also obtained by centrifugation of the original cell preparation through a stepwise bovine serum albumin gradient (cell layers I, II and III). The highest concentration of ir-bombesin (0.77 pmol/10(6) cells) was found in a cell population (cell layer I) enriched in noradrenaline (adrenaline/noradrenaline ratio of 0.6). At the subcellular level, ir-bombesin was mainly concentrated in the secretory granules (0.61 pmol/mg protein) along with catecholamines (1097 nmol/mg protein), but a relatively high concentration of ir-bombesin (0.26 pmol/mg protein) was also found in the microsomal fraction. Isolation and high performance liquid chromatography (HPLC) analysis of adrenomedullary ir-bombesin revealed the presence of four molecular forms, one of them corresponding to gastrin releasing peptide (GRP), another one (major peak) eluting closely to synthetic neuromedin B and another one coeluting with GRP-(18-27). HPLC analysis of the molecular forms of ir-bombesin in the microsomes and secretory granules indicated that GRP- and neuromedin B-like materials can be generated between the two fractions.

Acetylcholine↗
PubMed1986

Early manifestations and first-contact incidence of schizophrenia in different cultures. A preliminary report on the initial evaluation phase of the WHO Collaborative Study on determinants of outcome of severe mental disorders.

In a context of a WHO collaborative study, 12 research centres in 10 countries monitored geographically defined populations over 2 years to identify individuals making a first-in-lifetime contact with any type of 'helping agency' because of symptoms of psychotic illness. A total of 1379 persons who met specified inclusion criteria for schizophrenia and other related non-affective disorders were examined extensively, using standardized instruments, on entry into the study and on two consecutive follow-ups at annual intervals. Patients in different cultures, meeting the ICD and CATEGO criteria for schizophrenia, were remarkably similar in their symptom profiles and 49% of them presented the central schizophrenic conditions as defined by CATEGO class S+. However, the 2-year pattern of course was considerably more favourable in patients in developing countries compared with patients in developed countries, and the difference could not be fully explained by the higher frequency of acute onsets among the former. Age- and sex-specific incidence rates and estimates of disease expectancy were determined for a 'broad' diagnostic group of schizophrenic illness and for CATEGO S+ cases. While the former showed significant differences among the centres, the differences in the rates for S+ cases were non-significant or marginal. The results provide strong support for the notion that schizophrenic illnesses occur with comparable frequency in different populations and support earlier findings that the prognosis is better in less industrialized societies.

Adolescent↗
PubMed1985

Stereoselective disposition of ibuprofen enantiomers in man.

This study has examined the stereoselective disposition of the enantiomers of ibuprofen in four healthy male subjects following separate administration of racemic ibuprofen (800 mg) and of each enantiomer (400 mg). A mean of 63 +/- 6% of an administered dose of R(-) ibuprofen was stereospecifically inverted to the S(+) enantiomer. There were no measurable inversion of the S(+) to R(-) ibuprofen. The kinetics of the individual enantiomers were altered by concurrent administration of the respective optical antipode. It is likely that this change reflects an interaction between the enantiomers at plasma protein binding sites. It was found that formation of ester glucuronide conjugates stereoselectively favoured the S(+) enantiomer. The data have demonstrated that the pharmacokinetics of ibuprofen and other alpha-methylarylacetic acids cannot be interpreted adequately without studying the pharmacokinetics of the individual enantiomers.

Adult↗
PubMed1985

Pulmonary bombesin in experimentally induced asbestosis in rats.

The pulmonary levels of immunoreactive bombesin in normal rat lungs and rat lungs exposed to asbestos were determined. Experimental asbestosis was induced in rats by a single intratracheal injection of 5 mg or 10 mg UICC standard Canadian Chrysotile B while sham-operated control rats received only the saline carrier. At 1, 3, 6, and 9 months following instillation, 5 animals of each group were sacrificed and the lungs removed. A section was kept for morphologic analysis, while the remaining portion was submitted to acid extraction and later measured for bombesin content by radioimmunoassay (RIA). The Chrysotile B-exposed tissues displayed the characteristic features typical of the fibrotic state associated with asbestosis one month following exposure and thereafter. The pulmonary bombesinlike immunoreactivity ranged from 4.5-7.5 pmoles/g tissue in normal rat lung, and these levels remained unchanged at 1 and 3 months after asbestos exposure. However at 6 and 9 months, significant increases ranging between 2 and 2.5 fold were observed. The initial increases in bombesin levels occurred at a later time (6 months) than those already observed for vasoactive intestinal peptide (VIP) (3 months). However, VIP levels plateaued at 9 months, while those of bombesin were still increasing. High-pressure liquid chromatography (HPLC) coupled with RIA demonstrates the presence of two bombesin-immunoreactive peaks in normal rat lung, the major one coeluting with the mammalian bombesinlike peptide gastrin-releasing peptide (GRP) and the other one being presumably a C-terminal portion of GRP. These data indicate that immunoreactive bombesin and VIP are selectively increased at different times following asbestos instillation and that these changes occur after the onset of fibrosis and the appearance of well-defined fibrotic lesions.

Animals↗
PubMed1985

Effect of prolonged renal dysfunction on intravascular and extravascular pulmonary fluid volumes during left atrial hypertension.

To examine the development of pulmonary edema during experimental renal dysfunction, left atrial pressure was altered in 14 mongrel dogs divided into two groups. Group 1 was composed of seven control animals, and Group 2 was composed of seven animals with surgically induced renal failure (1 week of bilateral ureteral ligation). Data were obtained at two levels of matched transmural pulmonary vascular pressure (defined as mean left atrial pressure less serum protein osmotic pressure). In the animals with renal dysfunction, extravascular lung water (EVLW) (thermal-green dye technique) was higher at moderately (-1 to -2 mm Hg) and severely elevated (11 to 12 mm Hg) vascular driving pressures (11.5 +/- 1.2 cc/kg vs 10.6 +/- 0.8 cc/kg and 14.8 +/- 1.3 cc/kg vs 13.0 +/- 1.9 cc/kg, respectively, both P less than 0.05 vs control). Because protein osmotic pressure was lower in the renal failure group (15.0 +/- 1.8 mm Hg vs 18.4 +/- 1.4 mm Hg, P less than 0.05), greater accumulations of extravascular lung water occurred at lower levels of left atrial pressure (14.2 +/- 1.4 mm Hg vs 17.1 +/- 1.2 mm Hg, P less than 0.05; 26.8 +/- 2.6 mm Hg vs 29.5 +/- 2.3 mm Hg, P less than 0.01). In addition, when the ratio of EVLW/PBV (pulmonary blood volume) was examined in both groups at each stage of the experiment, the ratio was greater in the Group 2 animals at each elevated pressure, suggesting increased permeability with renal dysfunction. In conclusion, pulmonary edema formation occurs at lower left atrial pressures in the setting of sustained renal dysfunction, this phenomenon can be partially explained by lower protein osmotic pressure though altered pulmonary microvascular permeability may contribute to edema formation.

Animals↗
PubMed1984

Dynorphin and enkephalins in adrenal paraneurones. Opiates in the adrenal medulla.

Immunoreactive dynorphin (ir-Dyn), immunoreactive leucine-enkephalin (ir-Leu-Enk) and various other neuropeptides were measured in acid extracts of bovine adrenal medulla and isolated adrenal chromaffin cells. Their respective levels ranged as follows: Leu-Enk greater than Dyn greater than bombesin greater than vasoactive intestinal peptide (VIP) greater than neurotensin greater than substance P. Comparisons of the total catecholamine levels with the levels of Leu-Enk in both extracts gave ratios in the same order of magnitude (2600, tissue extract and 5000, cell extract). However, the catecholamine/Dyn ratio in the tissue extract (138 000) was much higher than that found in the cell extract (20 180), suggesting a possible selective degradation of Dyn in tissue extract as compared with cell extract or an induction of Dyn biosynthesis in cells which have been isolated from their natural microenvironment. Immunofluorescence staining of isolated chromaffin cell sections revealed the presence of ir-Dyn in 5 to 10% of the total cell population. To localize ir-Dyn in regard to Leu-Enk and catecholamines, adrenal chromaffin cells were separated into three populations (I, II, and III) on a stepwise bovine serum albumin (BSA) gradient. Relative high levels of ir-Dyn were measured in cell layer I (4 pmol/10(6) cells), a cell population enriched in noradrenaline. However, ir-Leu-Enk was more concentrated in cell layers II and III (5.3 and 8.3 pmol/10(6) cells), two populations enriched in adrenaline. Isolation and high pressure liquid chromatography (HPLC) analysis of adrenomedullary Dyn indicated the presence of at least five molecular forms corresponding to Dyn-(1-11), Dyn-(1-12), Dyn-(1-13), Ala-containing-Dyn-(1-13) and a nonidentified molecule eluting closely to Dyn-(1-13). These data indicate that adrenal ir-Dyn and ir-Leu-Enk have distinct cellular distributions. In addition, the identification of Dyn fragments in bovine adrenal medulla indicates that these short peptides may be considered as natural active forms of Dyn.

Adrenal Medulla↗
PubMed1984

Chemotherapy for metastatic non-small cell bronchogenic carcinoma: cyclophosphamide, doxorubicin, and etoposide versus mitomycin and vinblastine (EST 2575, generation IV).

Between March and December 1979, the Eastern Cooperative Oncology Group (ECOG) compared the CAVP16 (cyclophosphamide, doxorubicin, and etoposide) and MV (mitomycin and vinblastine) regimens in 200 patients with metastatic non-small cell bronchogenic carcinoma. Most patients were ambulatory (ECOG performance status, 0, 1; 75%) and had not received prior radiation therapy (76%). The CAVP16 regimen resulted in one complete and 13 partial responses (14%) and the mitomycin and vinblastine regimen resulted in two complete and 11 partial responses (13%). These results did not differ significantly (P = 0.45) nor did the results for median survival, 18 weeks for each regimen. Good performance status and prior surgical resection were positive predictors of improved survival. Toxicity was significant with eight drug-related deaths, six due to leukopenia and infection and one each due to renal failure and interstitial pneumonitis. CAVP16 resulted in significantly more serious and life-threatening toxicity (P less than 0.0001). Neither regimen is recommended for further study.

Aged↗
PubMed1983

Asbestos-related increase in pulmonary levels of vasoactive intestinal peptide (VIP).

Vasoactive intestinal peptide (VIP), leucine-enkephalin (Leu-Enk), dynorphin (Dyn), neurotensin (NT) and substance P (SP) were measured by radioimmunoassay in lung and bronchoalveolar lavage (BAL) fluids of sham operated control rats and rats exposed to asbestos (5 and 10 mg, single intratracheal injections) for 3 and 6 months. Among these peptides, VIP, Leu-Enk and Dyn were the most abundant with 6 to 25 pmoles per g of lung tissue as compared with 0.95 to 1.2 pmoles per g for the other neuropeptides. In the presence of asbestos, VIP levels were selectively increased up to 2.7 times in lung tissue and 4.3 times in BAL fluids. On high pressure liquid chromatography (HPLC), the immunoreactive VIP coeluted with synthetic VIP. It is concluded that this selective increase may be involved in the pathogenesis of asbestos-related diseases. Exposure to asbestos causes chronic inflammatory reactions in the lung which may lead to fibrosis (1) and increase the incidence of pleuropulmonary cancers (2). Little is known concerning the biochemical changes responsible for the deleterious effects of asbestos on pulmonary functions. Previous studies have documented the vast complexity and diversity of lung biochemistry including its ability to metabolize lipids, inactivate certain enzymes and produce physiologically active amines (3-6). Recently, the lung has been recognized as an important source of peptidergic substances. VIP and SP were reported to be localized in nerve terminals of the main airways and in axons of the parasympathetic conducts (7-11). Other neuropeptides including bombesin (12, 13), calcitonin (13, 14) and Leu-Enk (13) were also detected in the lung. However, these latter peptides were mainly confined to diffuse granule-containing cells also known as APUD cells (amine precursor uptake and decarboxylation cells) (15). The role of these neuropeptides in normal lung function and in pulmonary diseases is unknown. However, it has recently been demonstrated that APUD cells proliferate in the rat lung following asbestos inhalation (16) and lung exposure to carcinogens (17, 18). In addition, Moody et al. (19) and Sorenson et al. (20) have observed high levels of bombesin in human cell lines derived from small-cell lung carcinoma. It was then of particular interest to verify if lung exposure to asbestos can induce some changes in the levels of various neuropeptides. In the present study, we report that VIP is significantly increased in the lungs and BAL fluids of rats exposed to asbestos while no significant change in the levels of Leu-Enk, Dyn, NT and SP is observed.

Animals↗
PubMed1983

Distinct distribution of immunoreactive dynorphin and leucine enkephalin in various populations of isolated adrenal cromaffin cells.

The distribution of immunoreactive-dynorphin (ir-Dyn) in isolated subpopulations of bovine adrenal chromaffin cells was examined and compared with that of adrenaline (A), noradrenaline (NA) and ir-Leucine-Enkephalin (ir-Leu-Enk). Using a stepwise bovine serum albumin (BSA) gradient, various populations of catecholamine-storing cells were separated and designated as cell layers I, II and III. Cell layer I contained more NA than A; cell layer II contained slightly more A than NA whereas cell layer III was highly enriched in A. The original cell preparation contained 2.9 times more ir-Leu-Enk than ir-Dyn (4.7 and 1.6 pmoles per 10(6) cells, respectively). After separation of the cells on BSA gradient, ir-Dyn was mainly detected in cell layer I (4.0 pmoles/10(6) cells) whereas ir-Leu-Enk was concentrated in cell layer III (8.3 pmoles/10(6) cells). Both peptides were secreted in response to acetylcholine (5 x 10(-5) M), but the amount secreted was in accordance with the cell content in each peptide. After subcellular fractionation of the adrenal medulla, the neuropeptides were found in close association with catecholamines in the secretory granules. These results indicate that bovine adrenal chromaffin cells can be isolated according to their specific content in A, NA and opioid peptides and are consistent with the hypothesis of distinct biosynthetic pathways for Dyn and the Enk.

Animals↗
PubMed1983

Purification and identification of multiple forms of dynorphin in human placenta.

Immunoreactive dynorphin (ir-Dyn) and opiate-like peptides (OLP) were measured in acid (HC1) extracts of human placenta by the use of an antibody to synthetic Dyn-(1-13) and of the displacement of [3H]-naloxone binding to rat brain homogenates, respectively. The placenta contained 57.6 pmoles per g of ir-Dyn and 134.4 pmoles per g of naloxone binding equivalents. After passage of the extract through cartridges of Sep Pak C18, half of the OLP was eluted with ir-Dyn at 35% acetonitrile (ACN), the rest being eluted at 60% ACN. Both fractions obtained from Sep Pak were chromatographed separately on Sephadex G-50, the OLP of the 35% ACN fraction coeluting with the ir-Dyn speak and that of the 60% ACN fraction being eluted at the same volume as synthetic beta-endorphin. Conversely, the fraction of OLP coeluting with synthetic leucine-enkephalin (Leu-Enk) in these two chromatographies was minimal. The Dyn-immunoreactive material was further purified by high pressure liquid chromatography on reverse phase micro-Bondapak C18 columns to give three distinct peaks corresponding to synthetic Dyn-(1-11), Dyn-(1-13) and Dyn-(1-12), respectively. Our results indicate that the human placenta contains several forms of ir-Dyn which account for about half of its endogenous OLP.

Animals↗
PubMed1983

A randomized phase II study of m-AMSA (NSC 249992) and neocarzinostatin (NSC 157365) in non-small cell bronchogenic carcinoma. An Eastern Cooperative Group Study.

Eighty-nine patients with advanced non-small cell bronchogenic carcinoma were treated with either m-AMSA 120 mg/m2 intravenously every 3 weeks or neocarzinostatin 2.0 mg/m2 intravenously daily X 5 every 4 weeks. There were no responses in 40 evaluable patients who received m-AMSA and three partial responses (7.5%) in 40 patients who received neocarzinostatin. Two patients receiving m-AMSA had drug-related deaths. For m-AMSA the major toxicities were hematologic, while for neocarzinostatin the major toxicities were hematologic, gastrointestinal, and fever. We conclude that m-AMSA is inactive while neocarzinostatin has minimal activity in non-small cell bronchogenic carcinoma.

Aged↗
PubMed1983

Newborn care in family practice.

Official guidelines regarding the training of family practice residents in newborn medicine have been meager and general. Guidelines have traditionally focused on defining the requisite duration rather than the content of nursery rotations. A competency-based curriculum in newborn medicine is needed that defines requisite knowledge, skills, and attitudes; defines the appropriate role for the family physician in managing newborn problems; reflects the actual newborn experience of family physicians; is incorporated into residency training on a daily basis; and can be utilized in documenting resident competency in newborn health care. This paper describes the development, content, and daily implementation of a newborn curriculum that addresses these issues.

Family Practice↗
PubMed1982

Treatment of hemodialysis-related porphyria cutanea tarda with plasma exchange.

A patient with hemodialysis-related porphyria cutanea tarda was treated with plasma exchange. A rapid clinical response occurred coincidentally with a significant fall in the plasma porphyrin level. The level fell further over the following few months without additional therapeutic intervention, whereafter a slow rise occurred without recurrence of skin disease. We suggest that this form of treatment may be ideal for the patient with porphyria cutanea tarda and chronic renal failure in whom no alternative therapy is available for the cutaneous problem.

Adult↗