Questions
5. A patient with chronic-stable angina begins taking metoprolol, and once blood levels reach the therapeutic...

5. A patient with chronic-stable angina begins taking metoprolol, and once blood levels reach the therapeutic range the frequency and severity of angina attacks and the need for sublingual nitroglycerin were reduced. Which of the following states the direct pharmacologic action by which the beta-blocker produced the desired effects? A. Decreased myocardial oxygen demand

B. Dilated coronary vasculature

C. Directly inhibited angiotensin II synthesis

D. Reduced total peripheral resistance

6. A patient with newly diagnosed essential hypertension starts treatment with a commonly used antihypertensive drug at a dose that is considered to be therapeutic for the vast majority of patients. Soon after starting therapy the patient experiences crushing chest discomfort. ECG changes show myocardial ischemia. Studies in the cardiac catheterization lab show episodes of coronary vasospasm, and it is likely the antihypertensive drug provoke the vasospasm. Which antihypertensive drug most likely caused the ischemia and the angina?

A. Atenolol

B. Diltiazem

C. Hydrochlorothiazide

D. Lozartan

7. A 28-year-old woman is receiving drug therapy for essential hypertension. She subsequently becomes pregnant. You realize that the drug she's been taking for her blood pressure can have serious, if not fatal, effects on the fetus. As a result, you stop the current antihypertensive drug and substitute it with another drug that is deemed to be equally effective in terms of her blood pressure, and safer for the fetus. Which of the following drugs was she most likely taking before she became pregnant?

A. Alpha-Methyldopa

B. Captopril

C. Furosemide

D. Labetalol E. Verapamil

8. The use of propranolol as an antiarrhythmic agent is contraindicated in patients with:

A. COPD

B. Asthma

C. Severe heart failure

D. A and C

E. All of the above

In: Biology

(biochem) refering to the paper "A safer poppy" by Jenny Rood. It was published in The...

(biochem)

refering to the paper

"A safer poppy" by Jenny Rood. It was published in The Scientist, January 2018, vol. 31, 1, page 61. You can access this journal/magazine, for free, at the

www.the-scientist.com

What makes opioid drugs "double-edged" swords? Can the two sides of opioid drugs be separated? Why is the effort worth working on it?

In what directions research on receptors is going trying to solve the crisis? Are there several strategies?

Discuss strategies for finding safer alternatives to opioids: from target point of view and/or mechanism point of view.

Are there safer pain killer commercially available?

Give a nut-shell statement about the research in this field at the present.

In: Biology

1. a) What are some unique (derived) characteristics of the Goblin Shark? b) Does the Goblin...

1.

a) What are some unique (derived) characteristics of the Goblin Shark?

b) Does the Goblin Shark lose any characteristics that other similar animals have?

In: Biology

why is a tissue specific transcription factor important for tissue specific responses to inductive signals?

why is a tissue specific transcription factor important for tissue specific responses to inductive signals?

In: Biology

what is the role of a dna response element in inductive signaling?

what is the role of a dna response element in inductive signaling?

In: Biology

what is the role of a signal activated transcription factor in the induction of cell fate?

what is the role of a signal activated transcription factor in the induction of cell fate?

In: Biology

Kindly write a one page summary of the content below including important details. Thank you. Abstract...

Kindly write a one page summary of the content below including important details. Thank you.

Abstract Representing the 60 trillion cells that build a human body, a sperm and an egg meet, recognize each other, and fuse to form a new generation of life. The factors involved in this important membrane fusion event, fertilization, have been sought for a long time. Recently, CD9 on the egg membrane was found to be essential for fusion [1], but sperm-related fusion factors remain unknown. Here, by using a fusion-inhibiting monoclonal antibody [2] and gene cloning, we identify a mouse sperm fusion related antigen and show that the antigen is a novel immunoglobulin superfamily protein. We have termed the gene Izumo and produced a genedisrupted mouse line. Izumo −/− mice were healthy but males were sterile. They produced normal-looking sperm that bound to and penetrated the zona pellucida but were incapable of fusing with eggs. Human sperm also contain Izumo and addition of the antibody against human Izumo left the sperm unable to fuse with zonafree hamster eggs. Identification of Izumo To identify factors involved in sperm–egg fusion, we used a monoclonal antibody, OBF13, against mouse sperm that specifically inhibits the fusion process [2]. The antigen was identified by separation of the crude extracts from mouse sperm by two-dimensional gel electrophoresis and subsequent immunoblotting with the monoclonal antibody. We named the antigen ‘Izumo’ after a Japanese shrine dedicated to marriage. The identified spot was analyzed by liquid chromatography tandem mass spectrometry (LC–MS/MS), and ten peptides that were 100% identical to a part of the sequence listed in the RIKEN full-length database were found. The registered DNA sequence was confirmed by sequencing after polymerase chain reaction with reverse transcription (RT–PCR) with total RNA prepared from the testis. A human homologue was found as an unverified gene in the NCBI database. The gene encodes a novel immunoglobulin superfamily (IgSF), type I membrane protein with an extracellular immunoglobulin-like domain that contains one putative glycosylation site (Fig. 1a). Mouse Izumo was shown to be a testis (sperm)-specific 56.4-kDa antigen by western blotting with a polyclonal antibody raised against recombinant mouse Izumo (Fig. 1b). Izumo was also detectable as a 37.2-kDa protein by western blotting of human sperm with anti-human Izumo antibody (Fig. 1c). Izumo was not detectable on the surface of fresh sperm. Coinciding with the fact that mammalian sperm are incapable of fertilizing eggs when ejaculated and that fertilization occurs only after an exocytotic process called the acrosome reaction, both mouse and human Izumo became detectable on sperm surface only after the acrosome reaction (Fig. 1d, e). This would probably be because Izumo is not localized on plasma membrane of fresh spermatozoa but is hidden under plasma membrane and accessible after the acrosome reaction, as occurs with CD46 on mouse sperm [3]. Figure 1 Identification and characterization of Izumo. a, Izumo is a typical type I membrane glycoprotein with one immunoglobulin-like domain and a putative N-glycoside link motif (Asn 204). b, Izumo was detected exclusively in testis and sperm by western blotting. The tissues examined are, from left to right: brain, heart, thymus, spleen, lung, liver, muscle, kidney, ovary, testis and sperm. The arrowhead indicates mouse Izumo protein. c, Western blotting analysis of human Izumo protein from human sperm. The arrow indicates human Izumo protein. d, Immunostaining of Izumo in sperm from an acrosin-promoter-driven transgenic mouse line that has enhanced green fluorescent protein in the acrosome. Izumo was not detected in fresh sperm with intact acrosomes expressing EGFP (indicated by green arrows), but was revealed on acrosome-reacted (non-green fluorescent) sperm (stained red, shown by white arrowheads), when stained with the polyclonal antibody against mouse Izumo. e, Human sperm were also stained with polyclonal anti-human Izumo antibody (red). Acrosome-reacted human sperm (stained green with anti-CD46 antibody) were reactive to the antibody against human Izumo but the same antibody did not react to acrosome-intact (CD46-negative) sperm. Scale bar, 10 mm. 40 ANNUAL REPORT OF OSAKA UNIVERSITY—Academic Achievement—2004-2005 Establishment of Izumo-deficient mice To address the physiological role of Izumo in vivo we generated Izumo-deficient mice by homologous recombination. An Izumo targeting construct was designed to replace exons 2–10 with a neomycin-resistant gene (neor ). Both the targeting event in D3 embryonic stem cells and the germline transmission of targeted genes were confirmed by Southern blot analysis. In the homozygous mutant mice, the full-length messenger RNA and the Izumo protein were not detected. Because the disruption of a gene can cause a concomitant increase or decrease in some related genes, we examined CD46, sp56, CD55, CD147, and ADAM2, which were reported to be involved in sperm–egg interactions. We could not find a significant change in these protein levels in sperm after the deletion of Izumo gene. The fecundity of Izumo-deficient males Izumo −/−mutant mice were healthy and showed no overt developmental abnormalities. Izumo -/- females demonstrated normal fecundity. Izumo +/− males also showed normal fertilizing ability. However, Izumo −/− males were sterile despite normal mating behaviour and ejaculation, with normal vaginal plug formations. After observation of 28 plugs, nine pairs of Izumo −/− male and wild-type females were kept for another 4 months but no pregnancies were observed. In at least four different cases of gene knockouts that resulted in male sterility attributed to impaired zonabinding ability, the sperm also failed to migrate into the oviduct. However, disruption of Izumo did not cause any defect in sperm migration into the oviduct (data not shown, and there was no reduction of sperm motility in Izumo −/− sperm motility was measured 120 min after incubation by computer-aided sperm analysis (CASA; mean; s.e.m.=81.7±7.7% in Izumo +/− sperm and 77±8.9% in Izumo −/− sperm)). The sterile nature of Izumo −/− sperm was shown in the in vitro fertilization system (Fig. 2a). The impaired fertilization step undoubtedly followed zona penetration because sperm penetrated the zona pellucida and accumulated in the perivitelline space of the eggs (Fig. 2b). Fusion ability in Izumo-deficient sperm Syngamy can be considered to occur to two stages: binding of the sperm plasma membrane to that of the egg, and actual membrane fusion. Izumo −/− sperm were capable of binding to the plasma membranes of eggs whose zona pellucida had been mechanically removed [4] (Fig. 2c). In this system, the Izumo +/− sperm incubated for 2 and 6 h fused to eggs in approximate ratios of 4.5 and 6 sperm per egg, respectively, but no Izumo −/− sperm fused with eggs (Fig. 2c). Sperm can not fuse with eggs unless the former have undergone the acrosome reaction. To verify the acrosomal status of Izumo −/− sperm, we stained the sperm accumulated in perivitelline spaces with the MN9 monoclonal antibody, which immunoreacts only to the equatorial segment of acrosomereacted sperm [5]. The staining indicated that the Izumo −/− sperm had undergone the acrosome reaction (Fig. 2b) but failed to fuse with eggs. Development of eggs after intracytoplasmic sperm injection (ICSI) with Izumo-deficient sperm Because no offspring were fathered by Izumo −/− male mice, it was unclear whether the defect was limited to fusion or extended to later developmental stages. To address this question, we used ICSI to insert Izumo −/− sperm directly into the cytoplasm of wild-type eggs and bypass the fusion step. Eggs injected with Izumo −/− sperm were successfully activated and the fertilized eggs were transplanted into the oviducts of pseudopregnant females. The eggs implanted normally and the resulting embryos developed appropriately to term with rates similar to those of heterozygous mice. Human Izumo is also involved in sperm-egg fusion Sperm–egg fusion is known to be less species-specific than sperm–zona interaction. For example, human sperm can not penetrate the hamster zona pellucida but they can fuse with zona-free hamster eggs, and this system (zona-free hamster-egg sperm penetration test) has been used for the assessment of human sperm fertility. We first examined the contribution of mouse Izumo in a zona-free hamster-egg sperm penetration assay. As indicated in Fig. 3a, the mouse Izumo was essential not only in the homologous fusion system but also for heterologous fusion with hamster eggs. Similarly, when the anti-human Izumo polyclonal antibody was added to the incubation mixture, no fusion was observed, whereas the sperm treated with control IgG fused with eggs at an average of 5.9±0.7 sperm per egg. The total numbers of eggs observed were 23 and 29, respectively (n=3). These results indicated that human Izumo is involved in the fertilization process in human sperm (Fig. 3b). Rescued fertility of Izumo-deficient male by transgene The phenotypes of gene knockout mice are not always related Figure 2 Male infertility caused by Izumo disruption. a, In vitro fertilization of sperm from Izumo +/−and Izumo −/−mice. Unlike Izumo +/−, the eggs inseminated with Izumo −/− sperm had many sperm on their zona pellucida, owing to the failure of sperm–egg fusion that probably leads to the absence of zona-reaction to lessen the sperm-binding ability of the zona pellucida. b,Upper panel, accumulation of many sperm in the perivitelline space of the eggs recovered from the females mated with Izumo −/− males. Lower panel, sperm in perivitelline space labelled with acrosome reacted, spermspecific monoclonal antibody MN9. c, Fused sperm stained by Hoechst 33342 preloaded into the egg. The arrowheads show the fused sperm. to the disrupted genes but are sometimes caused by disruption of a neighbouring gene. To examine whether the phenotype was directly derived from the lack of Izumo on sperm, we performed a rescue experiment by crossing Izumo −/− mice with transgenic mouse lines generated to express Izumo by using the testis-specific calmegin promoter [6]. The sterile phenotype was rescued with the transgenically expressed Izumo on mouse sperm (Fig. 4). Discussion In the search for sperm surface proteins that function in sperm–egg plasma-membrane binding and fusion, various candidates such as DE, CD46, equatorin, Sperad and SAMP32 have been reported. ADAM family proteins are given the most attention for their possession of a putative fusion peptide (ADAM1) and disintegrin domain (ADAM2 and ADAM3). None of the mice possessing disrupted ADAM1a, ADAM2 and ADAM3 show a significant defect in the ability to fuse with eggs [7-9], but do show an impairment of sperm–zona binding ability. Similarly, CD46 disruption does not diminish fusion [3]. In contrast, CD9 on the egg surface is essential for the fusing ability of eggs [1] and some indications for the involvement of the binding of integrins to CD9 are postulated in reference to sperm–egg fusion. However, the disruptions of the most probable candidate integrin α6β1 cause no major influence on the fusing ability of eggs. Thus, for several years, postulated fertilization mechanisms were repeatedly changed as a result of gene disruption experiments. This suggests that the essential nature of the candidate gene must be judged after observing the phenotype of the gene-disrupted mice. In this context, Izumo is the first sperm membrane protein shown to be essential for fusion. It is not yet known whether sperm Izumo interacts with egg CD9, as occurs with placental IgSF protein PSG17; neither do we know why the localization of Izumo after acrosome reaction is not limited to the 41 Osaka University 100 Papers : 10 Selected Papers ANNUAL REPORT OF OSAKA UNIVERSITY—Academic Achievement—2004-2005 Figure 4 Transgene to express mouse Izumo under the control of calmegin promoter. a, The locations of primers A to E were indicated in this figure. b, lane 1; Izumo +/− mouse with intrinsic Izumo, lane 2 and 3; Izumo −/− mouse with transgenically expressed Izumo and Izumo His-tag, respectively. c, Litter size obtained by mating male mice with C57BL/6 wild-type mice. The group numbers are equal to those shown in b. The numbers in parentheses indicate the numbers of matings. References 1. Miyado, K. et al., Requirement of CD9 on the egg plasma membrane for fertilization. Science, 287, 321-4 (2000). 2. Okabe, M. et al., Capacitation-related changes in antigen distribution on mouse sperm heads and its relation to fertilization rate in vitro. J Reprod Immunol, 11, 91-100 (1987). 3. Inoue, N. et al., Disruption of mouse CD46 causes an accelerated spontaneous acrosome reaction in sperm. Mol Cell Biol, 23, 2614-22 (2003). 4. Yamagata, K. et al., Sperm from the calmegin-deficient mouse have normal abilities for binding and fusion to the egg plasma membrane. Dev Biol, 250, 348-57 (2002). 5. Manandhar, G. & Toshimori, K., Exposure of sperm head equatorin after acrosome reaction and its fate after fertilization in mice. Biol Reprod, 65, 1425-36 (2001). 6. Ikawa, M. et al., Calmegin is required for fertilin alpha/beta heterodimerization and sperm fertility. Dev Biol, 240, 254-61 (2001). 7. Cho, C. et al., Fertilization defects in sperm from mice lacking fertilin beta. Science, 281, 1857-9 (1998). 8. Nishimura, H., Cho, C., Branciforte, D. R., Myles, D. G. & Primakoff, P., Analysis of loss of adhesive function in sperm lacking cyritestin or fertilin beta. Dev Biol, 233, 204-13 (2001). 9. Nishimura, H., Kim, E., Nakanishi, T. & Baba, T., Possible Function of the ADAM1a/ADAM2 Fertilin Complex in the Appearance of ADAM3 on the Sperm Surface. J Biol Chem, 279, 34957-62 (2004). equatorial segment where fusion initially takes place. All we can say now is that continued study of this protein’s function will undoubtedly lead to a fuller understanding of the cell–cell fusion process in fertilization and perhaps in other somatic systems such as muscle cells or trophoblasts. The finding not only provides insight into the enigmatic fusion mechanism but also promises benefits in the clinical treatment of infertility and the potential development of new contraceptive strategies

In: Biology

Write a paragraph commenting on the amount of pressure applied by the cytoplasm and cell membrane...

Write a paragraph commenting on the amount of pressure applied by the cytoplasm and cell membrane against the cell wall under, Turgid state and a state of plasmolysis in an Elodea cell(s) ( the state of plasmolysis is caused by introduction of salt water(

In: Biology

IN YOUR OWN WORDS, describe the role(s) the following play in DNA replication: 1. Nucleotide 2....

IN YOUR OWN WORDS, describe the role(s) the following play in DNA replication:

1. Nucleotide

2. DNA polymerase

3. Helicase

4. Ligase

In: Biology

describe two ecological impacts ( one beneficial and one detrimental) of fungi

describe two ecological impacts ( one beneficial and one detrimental) of fungi

In: Biology

1. Describe the significance of phase 4 in the process of new drug approval. What is...

1. Describe the significance of phase 4 in the process of new drug approval. What is a goal of postmarketing surveillance (PMS) in a new drug approval process?

In: Biology

4. Describe the most commonly used herbs for the increase in immune response and for the...

4. Describe the most commonly used herbs for the increase in immune response and for the treatment of depression. Why labeling an herbal supplement as "natural" does not mean it is safe or without any harmful effects?

In: Biology

Explain the reason why an edible vaccine for HBV does not look likely to be produced...

Explain the reason why an edible vaccine for HBV does not look likely to be produced and the attempt to produce an edible vaccine for HBV is acting as a test case for other edible vaccones. What does the HBV outcome mean for the future of edible vaccines in general?

In: Biology

If a donor unit contains anti-D which was somehow missed by the antibody screen, would this...

If a donor unit contains anti-D which was somehow missed by the antibody screen, would this be detected by the major crossmatch if the recipient is Rh positive? Why or why not?

In: Biology

Describe and contrast the different mechanisms by which sperm are transported to the egg in ferns...

Describe and contrast the different mechanisms by which sperm are transported to the egg in ferns and in pine trees. Please be as much clear as you can.

In: Biology