Search PubMed⌕ Search

Biomedical subjects

R Green

Publications and source records attributed to R Green.

At least 217 records · Page 12Linked to original sources
PubMed1994

Transsexualism and the law.

Transsexuals pose dilemmas for the law in (a) defining a male or a female; (b) deciding what partners are legally acceptable for marriage; (c) assessing the best interests of children after divorce; (d) interpreting employment discrimination based on gender or handicap; (e) permitting public cross dressing; (f) reviewing third-party reimbursement for medical procedures that may be deemed cosmetic or experimental; (g) determining eligibility for sports competition; (h) meeting military needs; and (i) determining socially and medically acceptable treatment in prison. Leading law cases are reviewed in each area, with commentary on relevant research findings.

Civil Rights↗
PubMed1994

Waynoka wisdom.

Explore the source record for details and available documents.

Cardiology↗
PubMed1994

Washington State's unscientific approach to the problem of repeat sex offenders.

In 1990, Washington State enacted the Sexual Predator Act, allowing the civil commitment of sex offenders to a mental health facility for life if they are deemed to be sexual predators (repeat, hardcore offenders). They are released only upon proof that they are no longer a threat to others. This paper reviews the debate about this law and the recent literature on the treatment of sex offenders. We conclude that the Washington State law is unscientific, because the available treatments are not adequate to ensure future safety and because the law selects poor candidates for treatment. Finally, a comment is made about preventive detention effected by psychiatry, and an analogy made to the habitual drunk driver.

Commitment of Persons with Psychiatric Disorders↗
PubMed1994

Conformational lability of lipases observed in the absence of an oil-water interface: crystallographic studies of enzymes from the fungi Humicola lanuginosa and Rhizopus delemar.

Considerable controversy exists regarding the exact nature of the molecular mechanism of interfacial activation, a process by which most lipases achieve maximum catalytic activity upon adsorption to an oil water interface. X-ray crystallographic studies show that lipases contain buried active centers and that displacements of entire secondary structure elements, or "lids," take place when the enzymes assume active conformations [Derewenda, U., A. M. Brzozowski, D. M. Lawson, and Z. S. Derewenda. 1992. Biochemistry: 31: 1532-1541; van Tilbeurgh, H., M-P. Egloff, C. Martinez, N. Rugani, R. Verger, and C. Cambillau. 1993. Nature: 362: 814-820; Grochulski, P., L. Yunge, J. D. Schrag, F. Bouthillier, P. Smith, D. Harrison, B. Rubin, and M. Cygler. 1993. J. Biol. Chem. 268: 12843-12847]. A simple two-state model inferred from these results implies that the "closed" conformation is stable in an aqueous medium, rendering the active centers inaccessible to water soluble substrates. We now report that in crystals of the Humicola lanuginosa lipase the "lid" is significantly disordered irrespective of the ionic strength of the medium, while in a related enzyme from Rhizopus delemar, crystallized in the presence of a detergent, the two molecules that form the asymmetric unit show different "lid" conformations. These new results call into question the simplicity of the "enzyme theory" of interfacial activation.

Amino Acid Sequence↗
PubMed1994

Rapid HPLC determination of total homocysteine and other thiols in serum and plasma: sex differences and correlation with cobalamin and folate concentrations in healthy subjects.

High-performance liquid chromatography with fluorescence detection has been utilized for the rapid determination of total homocysteine, cysteine, and cysteinylglycine in human serum and plasma. Our earlier procedure (Anal Biochem 1989;178:208), which used monobromobimane to specifically derivatize thiols, has been extensively modified to allow for rapid processing of samples. As a result, > 80 samples a day can be assayed for total homocysteine, cysteine, and cysteinylglycine. The method is sensitive (lower limit of detection < or = 4 pmol in the assay) and precise (intra- and interassay CV for homocysteine, 3.31% and 4.85%, respectively). Mean total homocysteine concentrations in plasma and serum were significantly different, both from healthy male donors (9.26 and 12.30 mumol/L, respectively; P < 0.001) and healthy female donors (7.85 and 10.34 mumol/L, respectively; P < 0.001). The differences in total homocysteine between sexes were also significant (P = 0.002 for both plasma and serum). Similar differences were found for cysteine and cysteinylglycine. We found a significant inverse correlation between serum cobalamin and total homocysteine in men (P = 0.0102) and women (P = 0.0174). Serum folate also inversely correlated with total homocysteine in both sexes.

Adult↗
PubMed1994

Classes of primitive murine megakaryocytic progenitor cells.

We describe high proliferative potential colony-forming cells-megakaryocyte (HPP-CFU-Mk) from mouse bone marrow preparations using known cytokine combinations. These primitive precursors, which generate at least 80 megakaryocytes per colony, were detected from bone marrow populations enriched for primitive cells, either following treatment with 5-fluorouracil (5-FU) or after enrichment from normal bone marrow using immunological procedures. HPP-CFU-Mk were most reproducibly grown in the presence of interleukin-1 (IL-1) plus IL-3 plus IL-6, and mostly grew as a single large aggregate, rarely forming multiple foci. Cell separation studies showed that the HPP-CFU-Mk have membrane properties that characterized these cells as being intermediate between high proliferative myeloid primitive progenitors (high proliferative colony-forming cells [HPP-CFC]) and committed megakaryocyte progenitors (CFU-Mk). The data show that HPP-CFU-Mk can be designated as primitive cells on the basis of their being spared in vivo after 5-FU treatment, their proliferative potential to produce megakaryocytes, and their cofractionation with a proportion of primitive myeloid progenitor cells.

Animals↗
PubMed1993

Synthesis of 2,4-disubstituted thiazoles and selenazoles as potential antitumor and antifilarial agents: 1. Methyl 4-(isothiocyanatomethyl)thiazole-2-carbamates, -selenazole-2- carbamates, and related derivatives.

Methyl 4-(isothiocyanatomethyl)thiazole-2-carbamate and methyl 4-(isothiocyanatomethyl)selenazole-2-carbamate have been prepared via chemical transformations involving 2-amino-4-(chloromethyl)thiazole (1) and 2-amino-4-(chloromethyl)selenazole (2), respectively, as starting materials. The homoanalog, methyl 4-(2-isothiocyanatoethyl)thiazole-2-carbamate, was prepared from (2-aminothiazol-4-yl)acetic acid. All compounds prepared were evaluated for their ability to inhibit leukemia L1210 cell proliferation. Methyl 4-(isothiocyanatomethyl)thiazole-2-carbamate (7) was the most active compound in this screen, inhibiting the growth of L1210 leukemic cells with an IC50 = 3.2 microM. Mitotic blocking appears to be its primary mechanism of cytotoxic activity. Compound 7 also was the only compound which demonstrated significant in vivo antifilarial activity against the adult worms of Acanthocheilonema viteae in experimentally infected jirds. This compound was inactive against Brugia pahangi at a dosage of 100 mg/kg x 5 days.

Animals↗
PubMed1993

Synthesis of 2,4-disubstituted thiazoles and selenazoles as potential antifilarial and antitumor agents. 2. 2-Arylamido and 2-alkylamido derivatives of 2-amino-4-(isothiocyanatomethyl)thiazole and 2-amino-4-(isothiocyanatomethyl)selenazole.

The synthesis of a series of 2-arylamido and 2-alkylamido derivatives of 2-amino-4-(isothiocyanatomethyl)thiazole and 2-amino-4-(isothiocyanatomethyl)selenazole is described. In vitro antiproliferative evaluations were carried out using L1210 cells. The 2-(alkylamido)thiazole derivatives were moderately antiproliferative, with IC50's of 4-8 microM. A significant increase in activity was obtained for the arylamido derivatives, with IC50's of 0.2-1 microM. The results obtained for the selenazoles were similar to those for the thiazoles. 2-Benzamido-4-(isothiocyanatomethyl)-thiazole (19) was found to be a potent inhibitor of GMP synthetase. None of the compounds prepared in this study demonstrated antifilarial activity.

Animals↗
PubMed1993

Pre-Golgi degradation of yeast prepro-alpha-factor expressed in a mammalian cell. Influence of cell type-specific oligosaccharide processing on intracellular fate.

We demonstrate that expression of yeast prepro-alpha-factor in GH3 rat pituitary cells results in its degradation in an endoplasmic reticulum (ER) or early Golgi compartment, suggesting that this wild-type prohormone is recognized as abnormal or misfolded in the context of a mammalian ER. In GH3 cells, as in yeast, the nascent polypeptide is efficiently targeted to the ER, where it undergoes cleavage of its amino-terminal signal peptide and core glycosylation to form glycosylated pro-alpha-factor (gp alpha f). Subsequently, however, this species disappears from cells with a half-time of 25-30 min (including a 10-20-min lag), and no alpha-factor- or proregion-derived products can be detected. Localization of the degradative process to the ER is suggested by its occurrence in the presence of brefeldin A or chloroquine and by the endoglycosidase H susceptibility of the substrate. We present evidence that Asn-linked oligosaccharide processing, which differs in extent between yeast and mammalian cells, may be an important factor in determining degradation in this heterologous circumstance. When GH3 cells are treated with deoxymannojirimycin, an inhibitor of ER alpha-mannosidases, gp alpha f is essentially stable, suggesting that trimming of core oligosaccharides below Man8 (a process that does not occur in yeast) strongly promotes proteolysis. Inhibition of ER glucosidase activity by treatment with deoxynojirimycin, by contrast, considerably accelerates the disappearance of gp alpha f (t1/2 = 8-10 min). These data indicate that cell type-specific post-translational modifications of a secretory glycoprotein can substantially modify its recognition by the mammalian ER degradative apparatus.

1-Deoxynojirimycin↗
PubMed1993

Does fish oil benefit stone formers?

The possibility that dietary fish oil supplementation may benefit patients with hypercalciuric urolithiasis by decreasing calcium excretion and enhancing protective mechanisms has been studied in rats and humans. In experiments on rats in metabolic cages, fish oil inhibited experimental nephrocalcinosis induced by intraperitoneal calcium gluconate. There were no significant changes in urinary biochemistry. In a clinical study on 18 hypercalciuric recurrent stone patients fish oil significantly decreased urinary calcium excretion. This effect was accompanied by decreases in the excretion of magnesium and citrate. Oxalate excretion and urinary fibrinolytic activity were unchanged. Overall, fish oil had a limited impact on the risk profile for recurrent urolithiasis.

Adult↗
PubMed1993

Dose-response effects of adrenergic and cholinergic stimulation on atrial natriuretic peptide secretion from beating isolated guinea-pig atria.

1. The possible role of autonomic neurotransmitters in atrial natriuretic peptide secretion was investigated using spontaneously beating guinea-pig atria in vitro. Dose responses were determined for adrenaline, noradrenaline and acetylcholine and the selective alpha- and beta-adrenoceptor agonists phenylephrine and isoprenaline, respectively. Adrenoceptor effects were further studied using the selective alpha- and beta-adrenoceptor antagonists prazosin and propranolol, respectively, in conjunction with maximal adrenaline challenge. Results for rate and force of contraction and atrial natriuretic peptide secretion are expressed as a ratio (mean +/- SEM) of a 15 min treatment period (stage 2) to a corresponding pretreatment period (stage 1). 2. Adrenaline and noradrenaline caused dose-dependent increases in the rate and force of contraction and in atrial natriuretic peptide secretion with a peak secretory response at 2 x 10(-6) mol/l of 1.54 +/- 0.08 (P < 0.01) and 1.34 +/- 0.08 (P < 0.01) for adrenaline and noradrenaline, respectively. Acetylcholine decreased the rate and force of contraction, and ANP secretion was reduced to 0.47 +/- 0.06 at 3 x 10(-5) mol/l (P < 0.01). Isoprenaline increased the rate and force of contraction and atrial natriuretic peptide secretion with a peak secretory response of 1.52 +/- 0.22 at 2 x 10(-6) mol/l (P < 0.01). Phenylephrine increased the force but had no effect on the rate of contraction, and stimulated atrial natriuretic peptide secretion to 1.13 +/- 0.09 at 2 x 10(-5) mol/l (P < 0.05). After both alpha- and beta-adrenoceptor blockade, adrenaline was still able to significantly stimulate atrial natriuretic peptide secretion and positive inotropy.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1993

Influence of polar route schedules on the duty and rest patterns of aircrew.

The duty and rest periods of aircrew operating the polar route from London via Anchorage were recorded during five schedules which involved 1-, 2- or 3-day sojourns in Japan. Sleep throughout each schedule was fragmented, with naps before duty and short sleeps after arrival at a new location. Sleep disturbance rather than cumulative sleep loss appeared to be the overriding problem, and the shorter schedules had the most marked disturbances in sleep during the trip and during the immediate recovery period. Electroencephalographic studies are necessary to confirm these observations, and information on circadian rhythmicity is needed to define the circumstances which lead to persistence of sleep disturbance on return to Europe.

Adult↗
PubMed1993

Serum transferrin receptor level is not altered in invasive adenocarcinoma of the breast.

The transferrin receptor is expressed on the surface of rapidly dividing cells that require iron as a co-factor for essential redox reactions and deoxyribonucleotide synthesis. Transferrin receptors are expressed on the surface of breast carcinoma cells but not on benign breast tumor cells. In this study, the authors investigated whether transferrin receptor concentrations in the serum were elevated in patients with invasive adenocarcinoma of the breast. The transferrin receptor was isolated and purified from human placenta by affinity chromatography. The serum transferrin receptor concentration was determined using an enzyme-linked immunosorbent assay in 19 patients with invasive breast adenocarcinoma, 12 of whom had involvement of axillary lymph nodes. These results were compared with those from 16 normal age-matched female controls. In the invasive breast cancer group, the range of transferrin receptor concentrations was 2.60-7.34 mg/L (mean, 4.44 mg/L) compared with 2.85-8.80 mg/L (mean, 5.49 mg/L) in the control group. Nine patients with in situ adenocarcinoma of the breast had transferrin receptor concentrations of 3.68-6.66 mg/L (mean, 4.94 mg/L). For both the invasive carcinoma group and the in situ group, the means were not significantly different from those of the control group (P = 0.06 and 0.32, respectively). It was concluded that the differential expression of transferrin receptor on the surface of malignant tumor cells in adenocarcinoma of the breast was not reflected by changes in circulating transferrin receptor concentrations.

Adenocarcinoma↗
PubMed1993

Regulation of fluid secretion and intracellular messengers in isolated rat pancreatic ducts by acetylcholine.

1. We have studied the effects of acetylcholine (ACh) on fluid secretion and intracellular messengers in interlobular ducts isolated from the rat pancreas and maintained in short-term tissue culture. 2. Ductal fluid secretion was measured using micropuncture techniques. Intracellular free calcium ([Ca2+]i) and cyclic AMP concentrations were measured in single ducts using fura-2 microspectrofluorimetry and radioimmunoassay techniques respectively. Changes in the levels of these intracellular messengers were correlated with fluid secretion. 3. ACh stimulated ductal fluid secretion. The dose required for a half-maximal response was about 0.4 microM and maximal secretion was achieved with 10 microM ACh. These effects of ACh were blocked by atropine and by removal of extracellular Ca2+. 4. ACh was about four orders of magnitude less potent as an activator of ductal fluid transport than the hormone secretin; however, the maximal rates of fluid secretion evoked by these two agonists were similar. 5. ACh caused a dose-dependent rise in duct cell [Ca2+]i, but had no effect on cyclic AMP. In contrast, secretin increased duct cell cyclic AMP, but had no effect on [Ca2+]i. 6. The [Ca2+]i response evoked by ACh resulted from both mobilization of intracellular Ca2+ stores and influx of Ca2+ from the extracellular space. 7. The Ca2+ ionophore, ionomycin, mimicked the effect of ACh on ductal [Ca2+]i and fluid secretion. 8. We conclude that ACh stimulates fluid secretion from rat pancreatic duct cells by activating a 'Ca2+ pathway' which is distinct from the well documented 'cyclic AMP pathway' utilized by secretin.

Acetylcholine↗
PubMed1993

Pathology of renal dysplasia and bladder aplasia-hypoplasia in a flock of sheep.

Congenital renal disease was detected in a flock of sheep in the English Midlands over 2 successive years (1982 and 1983). A Suffolk ram was removed from the flock and test mated to unrelated Suffolk ewes in another flock; 14 of the resulting 43 lambs born in 1984 had an identical congenital renal disease. Kidneys were examined microscopically from 60 clinically affected neonatal lambs. Kidneys from 7 of the 60 clinically affected neonatal lambs (1, 1983; 6, 1984) were examined ultrastructurally and compared with kidneys from 3 healthy unrelated neonatal lambs. Most affected lambs examined (52/60) had bilaterally small kidneys (< or = 2 g) with fine intracortical cysts and distinct cortical and medullary zones. Kidneys were either grossly normal (3/60 lambs) or multicystic and of normal size to markedly enlarged (5/60 lambs). The bladder was absent or vestigial in most lambs. Microscopically, poorly differentiated ("primitive") tubules were present in renal cortex and medulla. Proximal convoluted tubules, where present, were formed by epithelial cells with distinctive round weakly autofluorescent intracytoplasmic inclusions with the ultrastructural appearance of atypical lysosomes. Loops of Henle, distal convoluted tubules, and juxtaglomerular-peripolar cell complexes were largely absent. Glomerular changes were minimal. Cystic dilatation of nephrons was restricted to proximal convoluted tubules lined by vacuolated epithelium. This distinctive congenital renal dysplasia of sheep was most likely inherited as a dominant trait with complete penetrance.

Animals↗
PubMed1993

G-CSF primed peripheral blood progenitor cells in autologous bone marrow transplantation: parameters affecting bone marrow engraftment.

G-CSF and GM-CSF enhance the rate of neutrophil engraftment in autologous bone marrow transplantation (ABMT) without significantly affecting platelet engraftment. Peripheral blood progenitor cells (PBPC) may enhance rates of engraftment of both neutrophils and platelets. We treated 49 patients undergoing ABMT with a course of G-CSF to obtain PBPC and infused these cells post-transplant with G-CSF in an attempt to determine factors which might correlate with enhanced BM engraftment. Forty-nine patients with Hodgkin's disease, non-Hodgkin's lymphoma or breast cancer undergoing unpurged ABMT were studied. G-CSF priming consisted of an outpatient 8 day course of 5 micrograms/kg/day followed by three leukaphereses (on day 5, 7 and 8) to collect PBPC. Patients then received a chemotherapeutic BMT preparative regimen followed by an infusion of PBPC, autologous BM and the reinstitution of G-CSF (16 micrograms/kg/day). BM engraftment was rapid. The median time to achieve 0.5 x 10(9)/l neutrophils was 10 days compared with a historical BMT control patient population receiving the same preparative regimens of 19 days (p = 0.001). Time to achieve a platelet count of 20 x 10(9)/l was 16 days compared with a historical control of 22 days (p = 0.001). Neutrophil engraftment occurred in all patients by day +14. Marrow engraftment correlated with the total number of CD34+ cells infused as well as the total number of mononuclear cells infused but not the total number of CD34+/CD33- cells infused. The amount of total blood volume pheresed significantly correlated with yield of total mononuclear cells. Prior exposure to radiation therapy negatively correlated with progenitor cell yield.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗