Millennium development goal 5: situation analysis.
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Africa South of the Sahara↗
Biomedical subjects
S L Mills
Publications and source records attributed to S L Mills.
Youth tobacco use research in the USA: progress and challenges.
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Adolescent↗
Coupling from AII amacrine cells to ON cone bipolar cells is bidirectional.
The AII amacrine cell is a critical interneuron in the rod pathway of the mammalian retina. Rod signals pass into cone pathways by means of gap junctions between AII amacrine cells and ON cone bipolar cells. Filling AII amacrine cells with Neurobiotin produces labeling of cone bipolar cells by means of these gap junctions. However, tracer injections into bipolar cells do not produce labeling of the AII network (Vaney [1997] Invest Ophthalmol Vis Sci. 38:267-273), which suggests that the AII/bipolar gap junctions allow the passage of tracer in only one direction. This mechanism stands in contrast to physiological results, which indicate that light adapted signals can pass from ON cone bipolar cells into the AII network (Xin and Bloomfield [1999] Vis Neurosci. 16:653-665). Here, we report that a variety of ON and OFF bipolar cells are sometimes anomalously coupled to the A-type horizontal cell network. These relatively rare examples do not result from dye injection errors, but seem to represent minor developmental errors. However, this provides a method to obtain Neurobiotin-filled cone bipolar cells without the necessity of impaling them with a microelectrode. Under these conditions, Neurobiotin spreads from ON cone bipolar cells into neighboring AII amacrine cells. The dye-coupled AII amacrine cells, positively identified by double labeling with an antibody against calretinin, were centered around anomalously coupled ON bipolar cells. These results indicate that AII/bipolar cell gap junctions allow tracer coupling in both directions, consistent with previous physiological results. The previous failure to detect the passage of neuronal tracer from injected bipolar cells to AII amacrine cells may reflect electrode damage or perhaps the asymmetrical voltage sensitivity of a heterotypic gap junction.
Animals↗
Rod pathways in the mammalian retina use connexin 36.
Many neurons in the mammalian retina are coupled by means of gap junctions. Here, we show that, in rabbit retina, an antibody to connexin 36 heavily labels processes of AII amacrine cells, a critical interneuron in the rod pathway. Image analysis indicates that Cx36 is primarily located at dendritic crossings between overlapping AII amacrine cells. This finding suggests that Cx36 participates in homotypic gap junctions between pairs of AII amacrine cells. Cx36 was also found at AII/cone bipolar contacts, previously shown to be gap junction sites. This finding suggests that Cx36 participates at gap junctions that may be heterotypic. These results place an identified neuronal connexin in the context of a well-defined retinal circuit. The absence of Cx36 in many other neurons known to be coupled suggests the presence of additional unidentified connexins in mammalian neurons. Conversely, Cx36 labeling in other regions of the retina is not associated with AII amacrine cells, indicating some other cell types use Cx36.
Animals↗
A series of biotinylated tracers distinguishes three types of gap junction in retina.
Gap junctions serve many important roles in various tissues, but their abundance and diversity in neurons is only beginning to be understood. The tracer Neurobiotin has revealed many different networks interconnected by gap junctions in retina. We compared the relative permeabilities of five different retinal gap junctions by measuring their permeabilities to a series of structurally related tracers. When large tracers were injected, the staining of coupled cells fell off more rapidly in some networks than others relative to Neurobiotin controls. Three distinctly different permeability profiles were found, suggesting that multiple neuronal connexin types were present. The most permeant to large molecules were gap junctions from A-type horizontal cells. The permeability of gap junctions of two types of amacrine cell were not distinguishable from those from B-type horizontal cells. The lowest permeability was found for gap junctions between cone bipolar cells and the AII amacrine cells to which they are coupled. Because only a single neural connexin type has been identified in retina, our results suggest more types remain to be found. To determine whether the unitary permeability of channels is altered by channel modulators, we reduced permeability with octanol and a cAMP analog. Although net permeability was substantially diminished, the proportion by which it declined was constant across tracer size. This suggests that these agents act only to close channels rather than alter individual channel permeabilities. This tracer series can therefore be used to contrast permeability properties of gap junctions in intact circuits, even at the level of individual channels.
Animals↗
Hypnotic activity of melatonin.
OBJECTIVE: To establish the effect of melatonin upon nocturnal and evening sleep. METHODS: Experiment I: The effect of melatonin (0.1, 0.5, 1.0, 5.0, and 10 mg), ingested at 23:30, was studied on nocturnal sleep (23:30-07:30) and core body temperature in 8 healthy volunteers. Performance was measured 8.5 h post-ingestion. On completion of the experiment dim light melatonin onsets (DLMO) were determined. Experiment II: The effect of melatonin (0.5, 1.0, 5.0, and 10 mg), ingested at 18:00, was studied on evening sleep (18:00-24:00) and core body temperature in 6 healthy volunteers. Performance was measured 6.5 h post-ingestion. Each experiment was placebo-controlled and double-blind with a cross-over design with temazepam (20 mg) as an active control. RESULTS: Experiment I: Melatonin (5 mg) reduced the duration of stage 3 in the first 100 min of sleep. Melatonin (0.1 mg) reduced body temperature 6.5 to 7 h post-ingestion. Temazepam increased stage 2, reduced wakefulness and stage 1, and increased the latency to REM sleep. Temazepam reduced body temperature 4.5 to 6.5 h post-ingestion. There were no changes in performance compared with placebo. DLMO occurred between 20:40 and 23:15. Experiment II: Melatonin (all doses) increased total sleep time (TST), sleep efficiency index (SEI) and stage 2, and reduced wakefulness. Temazepam increased TST, SEI, stage 2 and slow-wave sleep, and reduced wakefulness. There were no changes in body temperature or performance compared with placebo. CONCLUSION: Melatonin given at 23:30 has no significant clinical effect on nocturnal sleep in healthy individuals. Hypnotic activity of melatonin when given in the early evening (presumably in the absence of endogenous melatonin) is similar to 20 mg temazepam.
Adult↗
Antihistamines and aircrew: usefulness of fexofenadine.
INTRODUCTION: The aim of this study was to establish whether fexofenadine hydrochloride, an antihistamine, modulates daytime sleepiness or performance. METHODS: The effects of fexofenadine (120, 180, and 240 mg) on digit symbol substitution, tracking, and vigilance tasks, and on objective (multiple sleep latency test) and subjective sleepiness, were studied in six healthy volunteers (two males, four females, aged 20-34 [mean 26.5] yr) from 1 h pre-ingestion to 8 h post-ingestion. The study was placebo-controlled and double-blind with a six-way cross-over design. The centrally acting antihistamine, promethazine (10 mg), was used as an active control to confirm the sensitivity of the experimental procedures. RESULTS: There were no changes in performance or sleepiness with any dose of fexofenadine at any time, compared with placebo. Promethazine, compared with both placebo and fexofenadine, impaired performance on the digit symbol substitution task (2.5 h post-ingestion), vigilance task (2.5-5h post-ingestion) and tracking task (2.5-3.5 h post-ingestion), increased objective sleepiness (1.5-2.5 h post-ingestion) and subjective sleepiness (1.5-8h post-ingestion). CONCLUSION: Consideration may be given to the clinical use of currently licensed doses of fexofenadine (120-180 mg) by individuals involved in skilled activity. Fexofenadine may be potentially useful for aircrew.
Adult↗
Antibody to calretinin stains AII amacrine cells in the rabbit retina: double-label and confocal analyses.
The AII or rod amacrine cell is a critical interneuron in the rod pathway of mammalian retinae. In this report, it is shown that commercially available antibodies to the calcium binding protein calretinin may be used to label the population of AII amacrine cells selectively. Calretinin-positive amacrine cells had the morphological attributes of AII amacrine cells. Double-labeling procedures showed that calretinin-positive somata were surrounded by dopaminergic varicosities and that calretinin-positive dendrites enclosed rod bipolar terminals, both as previously described for AII amacrine cells. By analyzing the surrounding kernel for each labeled pixel in the rod bipolar image, it is shown here that AII processes are adjacent to rod bipolar terminals at a level that far exceeds the random overlap present in images in which one label was rotated out of phase. Such a spatial relationship is indicative of synaptic connections, as well described for rod bipolar input to AII amacrine cells. AII amacrine cells also were double-labeled for calretinin and parvalbumin; however, a scattergram analysis of red versus green intensity showed that the parvalbumin antibody stained additional unidentified amacrine cells. In conclusion, at the appropriate dilution, calretinin antibodies are a useful marker for AII amacrine cells in the rabbit retina.
3,3'-Diaminobenzidine↗
AII amacrine cells limit scotopic acuity in central macaque retina: A confocal analysis of calretinin labeling.
We have used calretinin antibodies to label selectively the mosaic of AII amacrine cells in the macaque retina. Confocal analysis of double-labeled material indicated that AII dendrites spiral down around descending rod bipolar axons before enveloping the synaptic terminals. Processes from a previously observed dopaminergic plexus in the inner nuclear layer were observed to contact the somata of calretinin-positive AII somata. Intracellular neurobiotin injection revealed that AII amacrine cells are tracer coupled to other AII amacrine cells and to some unidentified cone bipolar cells. An analysis of the retinal distribution of macaque AII amacrine cells, including an area in and around the fovea, showed a peak density of approximately 5,000 cells/mm(2) at an eccentricity of 1.5 mm. Staining of AII amacrine cells in central retina with antibodies to calretinin was confirmed by confocal microscopy. These results indicate that calretinin antibodies can be used to label the AII amacrine cell population selectively and that primate AII amacrine cells share many of the features of previously described mammalian AII amacrine cells. The peak AII cell density closely matched the peak sampling rate of scotopic visual acuity. Calculations suggest that, in central macaque retina, where midget ganglion cells are more numerous, AII amacrine cells form the limit of scotopic visual acuity (Wässle et al. [1995] J. Comp. Neurol. 361:537-551). As the ganglion cell density falls rapidly away from the fovea, there is a cross-over point at around 15 degrees eccentricity that matches the inflection point in a psychophysically derived plot of scotopic visual acuity versus eccentricity (Lennie and Fairchild [1994] Vision Res. 34:477-482). The correspondence between the anatomic and psychophysical data supports our interpretation that the anatomic sampling rate of AII amacrine cells limits central scotopic acuity.
Animals↗
Enhanced visualization of parathyroid tissue by infusion of a visible dye conjugated to an antiparathyroid antibody.
BACKGROUND: The antiparathyroid antibody BB5-G1 conjugated to cibacron blue, a blue dye, was intravenously infused to enhance parathyroid visualization. Previously, we demonstrated selective staining of human parathyroid implants in athymic nude mice after infusion of the conjugate. METHODS: Mice possessing implanted parathyroid tissue were randomized into the following: group I, infused with cibacron blue alone; group II, infused with the antibody/dye conjugate; and group III, infused with radiolabeled BB5-G1 alone. Implants were surgically explored. Three blinded observers ranked parathyroid visualization in the operative fields, and corresponding histologic sections were computer analyzed. RESULTS: Group II implants were easily visualized; groups I and III showed no staining. Group III showed high gamma counts. Subjective rankings and computer rankings correlated well (p < .05). Group II showed a higher mean staining intensity of 27.45 picogram protein product (PPP)/cell compared with 7.76 PPP/cell of group I (p = .002). CONCLUSION: Cibacron blue/BB5-G1 consistently enhances visualization of implanted parathyroid tissue.
Animals↗
Stability of monoclonal antibodies, Lym-1 and ChL6, and 2IT-BAD-Lym-1 immunoconjugate with ultra freezer storage.
UNLABELLED: Use of a single lot of monoclonal antibody (MoAb) or immunoconjugate for clinical studies provides efficiency of scale and consistent characteristics for MoAb-based pharmaceuticals. Lym-1, an anti-lymphoma mouse IgG2 alpha chimeric L6 (ChL6), an anti-adenocarcinoma mouse IgG2 alpha-human IgG1 chimera, and the immunoconjugate 2IT-BAD-Lym-1 were examined for stability following storage. METHODS: Lym-1, ChL6, and 2IT-BAD-Lym-1 were aliquotted with filtration and stored at -70 degrees C for up to 8.5 years. 2IT-BAD-Lym-1 stored for 6.3 years (lot A) was compared to freshly prepared 2IT-BAD-Lym-1 (lot B). MoAbs were thawed and examined yearly by gel filtration high performance liquid chromatography (HPLC), polyacrylamide gel electrophoresis (PAGE), cellulose acetate electrophoresis (CAE), and Scatchard analysis of antigen binding. 2IT-BAD-Lym-1 was evaluated by HPLC, CAE, and radioimmunoassay. To assure the in vivo significance of the in vitro studies, 2IT-BAD-Lym-1 lots A and B were labeled with 111In and their pharmacokinetics in BALB/c mice were compared. RESULTS: Lym-1 demonstrated stability over 8.5 years, providing the following ranges of data over the interval: 98-100% chemical purity (HPLC), 96-100% monomeric fraction (CAE), 8.18-8.46 antigen binding pKa (Scatchard). Similar results were obtained for ChL6 for 7.4 years. HPLC and PAGE of Lym-1 and ChL6 have not changed from original manufacturer specifications, and both MoAbs remain sterile and apyrogenic. No significant differences between 2IT-BAD-Lym-1 lots A and B were observed by in vitro evaluation or pharmacokinetics in mice. CONCLUSIONS: Lym-1, ChL6, and 2IT-BAD-Lym-1 as manufactured and stored for 8.5, 7.4, and 6.3 years, respectively, demonstrated retention of structural and functional integrity.
Animals↗
'Treatment mills' under the Federal Trade Commission Act.
This paper is based on a presentation made by the author at the meeting of the American Urological Association's Society for the Study of Impotence on April 12, 1997. The author addresses the general applicability of the Federal Trade Commission Act to advertising by so-called impotence 'treatment mills,' focusing in particular on the Federal Trade Commission's case in the matter of Genetus Alexandria, Inc. et al.
Advertising↗
Low-dose, fractionated radioimmunotherapy for B-cell malignancies using 131I-Lym-1 antibody.
PURPOSE: This trial was conducted to assess the toxicity and efficacy of 131I-Lym-1 in patients with either malignant B-cell non-Hodgkin's lymphoma (NHL) or chronic lymphocytic leukemia (CLL) using low-dose, fractionated radioimmunotherapy (RIT). MATERIALS AND METHODS: Thirty adult patients who had advanced B-cell malignancies (25 NHL and 5 CLL) had progressed despite standard therapy; 12 patients entered the trial with Karnofsky performance status (KPS) of equal to or greater than 60. Patients were treated with a series of intravenous doses of 131I-Lym-1 with a goal of reaching a cumulative dose in each patient of at least 300 mCi. All patients were Lym-1 reactive. Clinical responses and immediate toxicity were evaluable in all 30 patients and delayed toxicity in 26. RESULTS: Toxicity to Lym-1 antibody occurred with 28% of the 176 doses and was transient. Human antimouse antibodies (HAMA) were generated in 30% after a mean of 4 doses, but interrupted therapy in only 10% of the patients. Thrombocytopenia was dose-limiting; there were no deaths due to toxicity. Tumor regression occurred in 25 (83%) of the patients and was great enough, and durable enough, in 17 (57%) to qualify them as responders; 13 NHL patients and 4 CLL patients. Advanced disease often interrupted therapy prematurely. However, 18 patients received at least 180 mCi of 131I-Lym-1; 17 (94%) of these responded to the therapy. CONCLUSION: Although advanced disease often interrupted therapy prematurely, the results from 131I-Lym-1 therapy are clearly promising and warrant additional trials.
Adult↗
Cancer coverage and tobacco advertising in African-American women's popular magazines.
Mass circulating magazines offer an opportunity to inform large segments of the population about preventive health behaviors relevant for cancer control. We collected information about the number and type of cancer articles from January 1987 through December 1994 in Jet, Ebony and Essence magazines. These magazines each have a principal readership of African-American women and a paid circulation of 1,000,000 or more annually. Cancer articles were counted if the content was gender neutral or specifically targeted for women. There were 84 articles on cancer including 6 on lung cancer and 3 on other tobacco-related cancers. Nine additional references to lung cancer were mentioned under the general cancer category, but lung cancer was not the primary focus of the articles. There were 24 articles on breast cancer and 9 on cervical cancer over the 8 year period. Most of the articles (> 70%) were short fillers of less than one page in length. A prevention focus was included in 42.2%, 75.0%, and 71.0% of the cancer articles in Jet, Ebony, and Essence respectively. Of the 649 health articles, 116 were on cardiovascular disease. In contrast, there were 1,477 tobacco advertisements over the 8 years. The number of cancer articles was not significantly associated with the number of tobacco advertisements. Because tobacco-related cancers are entirely preventable and contribute to the significant cancer burden, the lack of coverage of tobacco-related cancers is a missed opportunity for health promotion among African-American females.
Adult↗
A calbindin-immunoreactive cone bipolar cell type in the rabbit retina.
We have studied the distribution of the calcium-binding protein calbindin in the adult rabbit retina by using a commercially available antibody and immunocytochemical methods. The most heavily labeled cells are A-type horizontal cells, but B-type horizontal cells are also lightly labeled by this antibody. Among the horizontal cells, there is a mosaic of small, well-labeled somata, which we have identified as a subset of ON cone bipolar cells. In addition, some wide-field amacrine cells and a few large ganglion cells are also labeled for calbindin. The calbindin bipolar cells form a regular mosaic with a peak density of approximately 1,700 cells/mm2, falling to 550 cells/mm2 in the periphery. They account for about one-twelfth of cone bipolar cells, and they are narrowly stratified deep in sublamina 4 of the inner plexiform layer immediately above the rod bipolar terminals. Double-label experiments using an antibody to protein kinase C (PKC) indicate that the calbindin bipolar cells are completely distinct from the population of rod bipolar cells. Rod bipolar cells outnumber the calbindin cone bipolar cells by a factor of four to five. Further double-label experiments show that the calbindin bipolar cells are also labeled for recoverin. The calbindin bipolar cells are well coupled to AII amacrine cells, and they account for roughly 23% of the AII coupled bipolar cells. This suggests that there are three to four additional ON cone bipolar cell types that are coupled to AII amacrine cells. The calbindin cone bipolar cell described in this paper shares many characteristics with a reconstructed cone bipolar cell that forms the most gap junctions with AII amacrine cells (Strettoi et al. [1994] J. Comp. Neurol. 347:139-149). We conclude that these different methodologies provide complementary descriptions of the same cone bipolar cell type. The calbindin antibody defines a subset of cone bipolar cells in the rabbit retina. The cells in this subset are almost certainly the deepest of the cone bipolar cells. The tight stratification of the calbindin cone bipolar cell suggests that the inner plexiform layer is stratified according to depth, with narrow functional divisions within the broad partition of sublamina b, where ON signals are processed. The strength of coupling between the calbindin cone bipolar cells and AII amacrine cells suggests this pathway plays a major role under scotopic conditions.
Animals↗
Parathyroid visualization with cibacron blue/BB5-G1.
BB5-G1 is a murine monoclonal antibody with proven affinity for human parathyroid tissue. The authors conjugated BB5-G1 to cibacron blue, a water-soluble dye, in an attempt to enhance intraoperative parathyroid visualization. Athymic nude mice possessing intramuscularly implanted human parathyroid tissue were infused with the conjugate, then surgically explored. Intraoperative findings were video-captured, then analyzed by three independent observers and by computer, generating subjective and objective data quantifying parathyroid visualization. Parathyroid tissue implants were stained and were easily visualized. The implants in the test mice displayed higher computer-generated color intensity ratings (mean, 10.25 units) compared to control mice (mean, 6.10 units) (p<0.5). Histologic sections confirmed the presence of dye and antibody within parathyroid tissue. This represents the first study to use such a conjugate to selectively enhance parathyroid visualization.
Animals↗
Differential properties of two gap junctional pathways made by AII amacrine cells.
The retina is sensitive to light stimuli varying over more than 12 log units in intensity. It accomplishes this, in part, by switching between rod-dominated circuits designed for maximum utilization of scarce photons and cone circuits designed for greater acuity. Rod signals are integrated into the cone pathways through AII amacrine cells, which are connected by gap junctions both to other AII amacrine cells and to cone bipolar cells. To determine the relative permeabilities of the two junctional pathways, we have measured the distribution of biotinylated tracers across this heterologous cell assembly after injecting a single AII amacrine cell. We found that neurobiotin (relative molecular mass, 286) passed easily through both types of gap junctions, but that biotin-X cadaverine (relative molecular mass, 442) passed through AII/bipolar cell gap junctions poorly compared to AII/AII gap junctions. Thus, the AII/bipolar cell channel has a lower permeability to large molecules than does the AII/AII amacrine cell channel. The two pathways are also regulated differently. Dopamine and cyclic AMP agonists, known to diminish AII-AII coupling, did not change the relative labelling intensity of AII to bipolar cells. However, nitric oxide and cGMP agonists selectively reduced labelling in bipolar cells relative to AII amacrine cells, perhaps by acting at the bipolar side of this gap junction. This suggests that increased cGMP controls the network switching between rod and cone pathways associated with light adaptation.
Amines↗
Generation of polyclonal catalytic antibodies against cocaine using transition state analogs of cocaine conjugated to diphtheria toxoid.
Six novel transition state analogs (TSAs) of cocaine (10-14 and 17) and one non-cocaine, p-aminophenylphosphonyl ester of cyclohexanol (19), were synthesized and characterized by 1H- and 13C-NMR and FAB-MS. (1R)-ecgonine methyl ester or cyclohexanol were subjected to phenylphosphonylation in the presence of dicyclohexyl carbodiimde (DCC) and 4-N,N-dimethyl aminopyridine (4-DMAP). TSA-IV (10), however, was synthesized from norcocaine which was protected with dibromoethane to yield 4 before acid hydrolysis, esterification and phenylphosphonylation were carried out. TSA-III (11) TSA-I (12) and (19), using various length spacer arms, were coupled with the immunogenic protein, diphtheria toxoid (DT). The TSAs coupled with DT were used to immunize mice and after appropriate boosts their sera were tested for the presence and titer of anti-TSA polyclonal antibodies using ELISA. Preliminary results show that the mice immunized with these TSAs produced high titers of polyclonal catalytic antibodies, except for (19), with the ability to hydrolyze the substrate 125I-4'-iodococaine in an in vitro assay, even in the presence of noncatalytic anti-TSA antibodies.
4-Aminopyridine↗