Model Questions for Pharmacology

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Model Questions for Pharmaceutical Microbiology (Food Microbiology)

1. What are the sources of impurities in pharmaceutical products? 
2. Explain the “bio-assay” linking with it to the drug discovery process. 
3. Highlight about the spoilage of pharmaceutical raw materials. 
4. What is pharmacopoeia and monograph development? Highlight about it in the context of Nepal.
5. Mention some quality assurance and management practices for pharmaceutical products. 
6. Describe preservation methods of pharmaceutical products. 
7. What are the factors affecting microbial spoilage of pharmaceutical products? How the humidity is crucial for it? 
8. What are the biological indicators of sterilization? Explain any two of them. 
9. Explain some methods of testing for the presence of antibiotics in meat. 
10. Explain some in vitro assays that are useful in drug discovery. 


11. What are the routes of drug administration?
12. What is pharmacodynamics? Explain with paracetamol (acetaminophen).
13. What are the "potency and efficacy" of drug? Explain with examples.
14. What is therapeutic index? Explain and draw a graph for warfarin.
15. How can we select a molecule to be taken as a medicine? Explain some theoretical aspects.


16. What are the components of augmentin? Explain the mode of action of augmentin. 
17. What are the criteria to select the antibiotics as the drug of choice? 
18. Enlist some biological sources and the antibiotics extracted/isolated from them. 
19. What are super-bugs? “Overuse of antibiotics may create super-bugs.” Explain the statement.
20. Describe the MIC and MBC. Explain some methods of searching new antibacterials.

Tips to Prevent the Spread of Infectious Diseases

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Let's admit it, nobody wants to be sick. From the common cold to more serious strains of the flu, many infectious diseases run rampant through modern society. You cannot just stop all contact with the outside world in order to stay healthy, but there are many ways you can help lessen your odds of contracting an infectious disease. If you want to stay healthy even when surrounded by sick people, here are six ways you can help prevent contracting an infectious disease.

1. Wash Your Hands
One of the most important ways you can be proactive in preventing the spread of infectious diseases is by washing your hands. Everything you touch can contain disease causing microbes and the best way to avoid these microbes from causing illness is by washing your hands. To get the most out of hand washing, make sure you washing your hands vigorously for about 20 seconds. This should wash away all the unhealthy germs.

2. Stop Sharing
If you truly want to protect yourself from an infectious disease, refrain from sharing personal items like toothbrushes, makeup, towels and razor blades. Sharing these items can increase your chances of contracting an infectious disease.

3. Get Vaccinated
A wide variety of vaccinations can help you protect yourself from contracting infectious diseases. If you want to eliminate your chances of obtaining one of these horrible illnesses, stay up to date on your vaccinations and get a yearly flu shot.

4. Cook Safely
Many infectious diseases are caused by unsafe cooking habits. Before you cook, make sure you thoroughly wash your hands so to avoid contaminating the food your are cooking. Also, make sure foods like vegetables are washed properly so to clean away possibly bacteria.

5. Safe Sex
Though it is not common in Nepal, because of cultural and tradition. Many infectious diseases are spread through sexual contact, and that is why it is important to wear a condom each time your have sex. If you are in serious relationship, ask your partner about his or her sexual past and if necessary, have that person submit to std testing if you want to engage in sexual acts without the use of condoms.

6. Travel Cautiously
In a variety of countries, there are an abundance of diseases that are not necessarily seen in America. Before you travel abroad, make sure you are aware of the types of illnesses that are common to the country you will be visiting. Be sure to get the vaccinations needed for a health and safe vacation.

Fortunately, the risk of contracting an infectious disease can be minimized greatly if you follow the six above listed tips. In order to protect your health, always remember to wear a condom, be a cautious traveler, cook food properly, wash your hands, get vaccinated, and never share personal items. At that point, you can be certain that you will be doing all you can to help protect yourself from contracting an infectious disease.

This is guest post by Ian Watertown who writes about health, travel & more here.

Identification and Classification of Bacteria; Microscopy to MALDI; May be Useful for Therapy Strategy

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Bacterial diseases are responsible for the highest number of death than any other diseases. Although developed countries have been reducing the death cases of bacterial diseases, countries like Nepal is still striving against it. However, recent cases of Germany and Haiti where Escherichia coli and Vibrio cholerae had infected and killed many human beings, indicates a terrible situation may happen anywhere in the world. Many techniques have been being used to identify and get rid of bacterial diseases. In recent days, ribotyping and PCR are being used to identify bacterial strains as the gold standard method. MALDI could be the most efficient method in future days to identify such strains along with putative antibiotics sensitivity pattern. I had described the methods so far used (and future uses) in a seminar and attached here. This is not complete, if you are interested, mail me to get the slides.

Please wait for few seconds in case of slow internet.

नायक राजेश हमाल र सुक्ष्मजीवहरु

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कलाकार / नायक राजेश हमाललाई महानायक बनाएर लेखेका टिपोट को थुप्रो लागिसकेछ । निसन्देह, यो हाँस्य प्रायोजनको लागि मात्र लेखिएको हो । तर, भर्खर-भर्खर Microbiology पढ्न सुरु गर्नेहरुको लागि Bacteria/Virus को characterहरु सम्झिन सजिलो हुन सक्छ ।

1. राजेश दाइलाई त माईक्रोस्कोप नै नचाहिने रहेछ ब्याक्टेरिया हेर्न को लागि ....
2. राजेश दाइ सानो हुँदां Staphylococcus र Streptococcus को गुच्चा खेल्नुहुन्थ्यो रे ।
3. राजेश दाइ सानो हुँदां Escherichia coli र  Vibrio cholera को डण्डीबियो  खेल्नुहुन्थ्यो रे ।  एकदिन, E. coli डण्डीले V. cholera गुलीलाई अलि जोडले हिर्काउनुभएछ, त्यसैले आजसम्म पनि V. cholera बाङ्गोको बाङ्गै छ । 
4. HIV त राजेश दाइसँग डराएर पो रहेछ, CD4 T-cell भित्र लुकि-लुकी बस्ने । 
5. राजेश दाइको लामो कपाल देखेर पो Salmonella typhi पनि peritrichous (झुसे) भएको रहेछ ।
6. २०५१ सालमा नेपालमा ठुलो खडेरी परेको थियो, किन भनेर बुझ्दै जांदा त राजेश दाइले Agaricus biospora (mushroom) को छाता बनाएर ओढ्नु भएको रहेछ ।
7. राजेश दाइले एउटा भुस्याहा कुकुरलाई गोली हान्नु भएछ, गोली लाग्यो, घाऊ-रगत देखिएन, तर पानी देखी डराउने मात्र भएछ, १४ दिनपछी बल्ल कुकुर मरेछ । यसपल्ट त राजेश दाइपनि अचम्म पर्नुभएछ । (Bullet shaped Rhabdovirus).
8. राजेश दाइको 'देउता' चलचित्र हेरेपछि Proteus त एकै ठाउँमा बस्न नसक्ने चकचके भएछ । (Swarming motility of Proteus spp.)

बांकी यता     http://www.facebook.com/hamalrajesh
                http://xnepali.net/np/240
बिष्णु प्र. मरासिनी

Epidemics of Diarrhea due to Escherichia coli (Shiga toxin producing enterohemorrhagic) in Europe

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Recently, enterohemorrhagic Escherichia coli (EHEC) strain has infected over 3,500 and kills over 40 people in the Europe and most of them are German [1]. Initially, it was blamed to salad and vegetables and the farmers for the cause of transmission, as concluded by case-control study. But the causative bacterial strain, EHEC O104:H4 has not been found in any of these salad and vegetables samples. Then authorities realize farmers were not culpable. Then they withdraw the blame with apology and announce the compensation for farmers. Now suspecting on bean, sprout, and agricultural practice [2].

EHEC O104:H4 is a type of E. coli classified on the basis of somatic O-antigen (over 170 different type: 1-170), and flagellar H-antigen (over 50 different types: 1-50). In E. coli, there are different chemical structure and functional group comprising lipopolysaccharide of plasma membrane (O-antigen), polysaccharide of  capsule (K-antigen) and flagella (H-antigen). Combining of these different antigens there could be thousands of different types of E. coli. The infective EHEC O104:H4 is new to Europe but this strain was reported from Korea in 2006 [3]. Does this means this strain is shipped from Korea? Certainly not, or needs exigent research.

Every organism has the tendency to adapt the environment with necessary genotype reshuffle or addition, and phenotypic variation, suitable to survive, as Darwinism. Bacterial strains also, always tend to increase virulence and pathogenicity by adapted gene transfer and mutation. In latent type of infection, plasmid and/or gene transferred from virulent strain to non-virulent may get proliferated for several months without symptom and unknown to health professional. This may be the one of the possible reason for outbreak in Europe, which is still under research to find the source of infection. So, the organism whose reservoir is the environment, they proliferated when the environmental condition becomes optimum, as said by Rita Colwell [6].

Vibrio, Escherichia has the environmental reservoir unlike smallpox and polio virus. So they are always prone to infect mammal once environmental condition become favourable. E. coli is even more dangerous as it is opportunistic pathogen and can acquire antibiotic resistance as well as virulence.

In my study (in NAST), some strains of E. coli were found to be resistant against all commonly used antibiotics (courtesy: Nabaraj Dahal, Pankaj Baral, and Sanjiv Neupane). This shows it is the dreadful strain having most flexibility in genetic variation among bacterial kingdom. However, the innovation and more research on antibiotics may enervates its massive proliferation.

Multi-drug resistant E. coli reconfirmed on M-endo agar.

Antibiotics sensitive E. coli (ATCC 25922) reconfirmed on M-endo agar.

Even in the Europe, the bacterial strain can invade people where living standard is high as well as good sanitation, well managed health system. Also, Nepal had faced problem of diarrhoeal epidemics and hundreds of people died in remote area, two years ago. But it was different scenario, poor people were lack of medicine and ORS.
Few months ago, an unprecedented outbreak of cholera in Haiti was the reason to blame Nepalese peacekeeping soldier. But neither stool nor rectal swab nor antibody test of these soldiers showed positive result of V. cholera (or was not investigated). Even no one could be verified as carrier. And probably, the sample of drinking water, seawater and sewage from different source was not analysed properly to make a conclusion. Only the co-incidence was the bacterial strain found there resembled with the South Asian strain, which is not only confined in Nepal but also other South Asian countries like Bangladesh, India, Pakistan etc.

References:

1. European Centre for Disease Prevention and Control,  Stockholm, Sweden, 22 June 2011, 11:00
2. Editorials, 16 June, 2011, Nature, Vol. 474, 251
3. Woo Kyun Bae, et al., Jun 2006, Yonsei Medical Journal, Vol. 47(3), 437-439
4. Marian Turner,  9 June, 2011, Nature, Vol. 474, 137
5. Kai Kupferschmidt, 10 June 2011, Science, Vol. 332, 1249-1250
6. Martin Enserink, 5 November 2010, Science, Vol. 330, 738-739

Cholera in Haiti and Association to South Asia and Scientific Study to Reduce Recurrence

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In the fall of last year, unprecedented outbreaks and epidemics of cholera in Haiti agitated locals, news media, health workers. There has been a long debate about these epidemics. The situation has been highlighted by famous science journals and has come to my attention.

Although the cholera outbreak had been diminishing, and the overall fatality rate was down to 2 % from earlier 9%, and 4,550 deaths and 231,070 cases were reported, still there were few cases, as United Nations, Geneva said at the beginning of February. The serotype of the causative agent, Vibrio cholerae, has been identified that resembles with South Asian strain. The mortality rate of untreated cholera is 50-60% (one of the highest mortality rates).

Transmission
Vibrio cholerae is transmitted to humans via the fecal-oral route via water or food. The reservoir of the organism is suspected of the aquatic environment. In its extreme manifestation, cholera is one of the most rapidly fatal illnesses known.

Clinical Symptoms
Cholera begins with the sudden onset of massive diarrhea, excretion of protein-free fluid and associated electrolytes, bicarbonates, and ions within a day or two. This loss of fluid leads to dehydration, anuria, acidosis, and shock. The watery diarrhea is speckled with flakes of mucus and epithelial cells ("rice-water stool") and contains enormous numbers of vibrios. The loss of potassium ions may result in cardiac complications and circulatory failure.

(Technical Terms Starts)
"Vibrio cholerae , Morphology and Culture
It is a Gram-negative non-sporing, non-capsulated, curved rod, motile, monotrichous (single polar flagellum), oxidase-positive (distinguished from enteric), glucose fermenter, non-lactose fermenter bacterium. Widely used enrichment mediums for this bacterium are; alkaline peptone water (APW), Cary-Blair transport medium, etc. And the common selective media for the isolation are; alkaline bile salt agar (BSA) medium (colonies are very similar to those on nutrient agar), Monsur's gelatin Tauro cholate trypticase tellurite agar (GTTA) medium (small translucent colonies with a grayish-black center), Thiosulpbate citrate bile salt (TCBS) agar medium (yellow nucleated colonies), polymyxin-mannose-tellurite (PMT) agar medium (differentiate between V. cholerae O1 from V. cholerae non-O1 based on mannose-fermentation), etc.

Disease Mechanism
V. cholerae start to produce the toxic proteins (cholera toxin, CTX / CT) only after reaching the intestine. It is an oligomeric complex made up of six subunits: one (A subunit), and five (B subunit). The B subunits bind to GM1 gangliosides on the intestinal epithelium cells. So the protein enters the cell via receptor-mediated endocytosis. Then the A1 subunit becomes free and binds with ADP-ribosylation factor 6 (Arf6), which permanently ribosylate the Gs alpha subunit of the heterotrimeric G protein. This results in constitutive cAMP production and pumps out Cl⁻, HCO₃−, etc., into the lumen of the small intestine which prevents sodium ions from entering the cell, and these ions create a salt-water environment, which through osmosis can pull up to 6 L of water per day through the intestinal cells, creating the massive amounts of diarrhea, and rapid dehydration.  Virulent strains of V. cholerae is due to temperate bacteriophage called CTXf or CTXφ. V. cholerae is well adapted and can, economically, produce different proteins in the different environments e.g., in the intestine, TcpP/TcpH proteins, which, together with the ToxR/ToxS proteins, activate the expression of the ToxT regulatory protein. ToxT then directly activates expression of cholera toxins, and allowing the bacteria to colonize the intestine."(Technical Terms Finished)

Risk Factors
For cholera, anybody can be at risk, i.e., there is no correlation between the vulnerability of infection and age, gender, malnutrition status, etc. It is one of the dangerous infectious diseases that can kill healthy people quickly. After the onset of symptoms, a victim may die within 4 hours to few days if no treatment is provided. However, people whose stomach is making fewer amounts of gastric acid than normal or recently had stomach surgery, or taking drugs that inhibit gastric acid production or a person of blood type O, are at higher risk. In Peru, virtually all indigenous people have blood type O and were at higher risk.

In Nepal, May-July is the main season of cholera outbreaks.

Treatment of Cholera
Treatment involves the rapid intravenous replacement of the lost fluid and ions. Following this replacement, the administration of the isotonic maintenance solution should continue until diarrhea ceases. With this simple treatment, the mortality rate of cholera can be reduced ten-fold. A few antibiotics (e.g. tetracyclines) may shorten the duration of diarrhea and reduce fluid loss.
A few years ago, I got a chance to study V. cholerae, 01, El Tor, Ogawa biotype, while I was in NAST (former RONAST), the strain was kindly provided by Mr. Nabaraj Dahal, Patan Hospital. It was not so dangerous in terms of antibiotics resistance as compared to other strains, I investigated, such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, etc., which were almost all commonly used antibiotics resistant. Diarrhea due to enteropathogenic E. coli is more complicated than cholera, in therapy.
The problem with the management of cholera is the consumption of unhygienic food and contaminated water. Contamination problem is mainly during both dry and rainy seasons. This is significantly enhanced due to drinking water pipe, which remains together with a sewage pipe, and in some places, drinking water pipe remains inside sewage Hume pipe.
In Haiti, cholera had proliferated due to floods. Certainly, floods not only contaminate drinking water but also destroy human's habitat and obstacle the disease treatment strategy. The flood made a connection between seawater and drinking water and the possibility of flow of V. cholerae from seawater to drinking water.
There are many places in Nepal where people rely on the river, stream for drinking water, so they are always at risk of these kinds of diarrhoeal diseases. Two years ago, the death of more than 200 people due to the epidemics of diarrhea (one of the simple/neglected diseases), in the rural area of Nepal indicates inaccessibility of modern medicine, and in fact, they still have to rely on medicinal plants and rituals.

Make pure water

Water purifier operated by bicycle

Recently, Singapore based water company, Glowtec has discovered a water purifying filter system, which can filter Decaliters of pure water within a minute (800 liter/hr). This can be operated by chain and the paddle of bicycle, and it can be transported anywhere as it is simple and light. It has been found very effective and significantly reduced the incidence of waterborne diseases in the flood-affected area of Pakistan, Myanmar, Yemen, Taiwan, the Philippines, and Vietnam. Vaccination is a good option to avoid cholera epidemics. Nepal, and probably all developing countries can't afford the cost and also, V. cholerae has a high mutation rate and new vaccination antigen and strategy needed within a short period for full coverage. People should keep re-hydration solutions like Jeevanjal, and should be immediately available in each home.

Acknowledgment: I thank Dr. Joachim Schindler for reviewing and some suggestions.
Picture : Quantum geoservices

References:

1. Martin Enserink, Science, 330, 5 November 2010, p. 738-739, Haiti’s Outbreak is Latest in Cholera’s New Global Assault
2. Martin Enserink, Science, 331, 28 January 2011, p. 388-389, Despite Sensitivities, Scientists Seek to Solve Haiti’s Cholera Riddle
3. Declan Butler, Nature, 468, p. 483-484 (2010), Cholera tightens grip on Haiti
4. David Cyranoski, Nature, 469, p. 273-274 (2011), Cholera vaccine plan splits experts
5. Kalpit P., Asianews, 2009 July 23, Epidemic hits western Nepal, More than 200 dead.
6. Katherine Harmon, ScientificAmerican, 25 October 2010, Why Is Cholera Spreading in Haiti Now?  
7. Debora MacKenzie, NewScientist, 15 November 2010, Haiti faces years of cholera
8. Debora MacKenzie, NewScientist, 07 December 2010, Haiti: Epidemics of denial must end
9. Debora MacKenzie, NewScientist, 10 December 2010, Haitian cholera strain could dominate the Americas

My Interest in Isolation and Identification of Escherichia coli from Urine Sample

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The greenish shining colony in M-endo Agar distinguish E. coli from other Coliforms that help to separate E. coli from other bacteria present in stool and urine sample. Also, this method and media can be used to check contamination after antibacterial assay of E. coli. This method saved my time to identify by various sub-culture test.

Isolation and Identification of Salmonella spp. from Clinical/Food Sample

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               The red colonies with black centers and media turn red (phenol red as indicator) in Xylose lysine deoxycholate (XLD) agar media distinguish Salmonella spp. from other coliforms that help to separate from other bacteria present in clinical blood/stool and food sample. Also, this method and media can be used to check contamination after antibacterial assay of Salmonella spp.

               Salmonellae can metabolize thiosulfate and produce hydrogen sulfide, hence black centers seen in colony but Shigellae can't and remains pink colony. Other coliforms are seen as yellow/orange colonies.
                Thus I separated Salmonella spp. very quickly from rest of the organisms.

 

microscope

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U.S. scientists are using a new form of scanning microscopy to simultaneously study physical and electronic profiles of metal nanostructures.

Researchers at the National Institute of Standards and Technology and University of Colorado-Boulder say the new instrument — the scanning photoionization microscope — is expected to be particularly useful for analyzing the make-up and properties of nanoscale electronics and nanoparticles.

The scientists said the instrument combines the high spatial resolution of optical microscopy with the high sensitivity to subtle electrical activity made possible by detecting the low-energy electrons emitted by a material as it is illuminated with laser pulses.

The technique potentially could be used to make pictures of both electronic and physical patterns in devices such as nanostructured transistors or electrode sensors, or to identify chemicals or even elements in such structures.

“You make images by virtue of how readily electrons are photoejected from a material,” said NIST fellow David Nesbitt, leader of the research group. “The method is in its infancy, but nevertheless it really does have the power to provide a new set of eyes for looking at nanostructured metals and semiconductors.”

The instrument is described in the journal Chemical Physics.

Copyright 2006 by United Press International. All Rights Reserved.

How shigella causes dysentery

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French scientists say they believe they’ve discovered how shigella bacteria survive in the gut to be able to cause dysentery.
Laurence Arbibe and colleagues at the Pasteur Institute in Paris found a protein produced by shigella is injected into host cells and blocks production of immune signals required for preventing the infection.
Shigella affects millions of people worldwide, killing hundreds of thousands annually.
The researchers studied Shigella flexneri infection of human colon cells to understand the bacterial factors required to initiate disease. Shigella bacteria are known to inject up to 20 proteins into intestinal cells for the purpose of promoting infection and for dampening immune responses.
They found one of the injected proteins, OpsF, could prevent gut cells from switching on genes involved in immune responses. As a consequence, Shigella flexneri avoids being killed by their host’s immune cells and is able to spread throughout the gut.
The scientists say their study highlights the precision with which pathogens such as shigella can dramatically alter host cells. It also suggests blocking OspF may provide a target for treating bacterial dysentery.
The study is reported in the January issue of the journal Nature Immunology.