Author: Neelam Maurya

Moist heat during the process shown in the picture below kills all of the following microorganisms, EXCEPT?

A. Coxiella burnetii.

B. Brucella.

C. Salmonella.

D. Mycobacterium.

Correct Answer » A Explanation

Ans:A. Coxiella burnetii

The process shown in the picture above represents Pasteurization.

Pasteurization

• It is a process that kills microbes (mainly bacteria) in food and drink.

• It is used widely in the dairy industry and other food processing industries to achieve food preservation and food safety.

• Unlike sterilization, pasteurization is not intended to kill all microorganisms in the food.

• Instead, it aims to reduce the number of viable pathogens so they are unlikely to cause disease.Spores are not affected by pasteurization. Commercial-scale sterilization of food is not common because it adversely affects the taste and quality of the product.

• This is considered adequate for destroying almost all yeasts, molds, and common spoilage bacteria and also to ensure adequate destruction of common pathogenic, all non-sporing pathogens such as mycobacteria, brucellae and salmonellae but not Coxiella burnetii, which causes Q fever.

• Coxiella burnetii is relatively heat resistant and may survive the holder method.

• The temperature employed is either 630C for 30 minutes (the holder method) 720C for 15-20 seconds (the flash process) followed by cooling quickly to 130C or lower.

• The dairy industry routinely uses to test to determine whether products have been pasteurized: the phosphatase test (phosphatase is an enzyme naturally present in milk). If the product has been pasteurized, phosphatase will have been inactivated.

A. Steam under pressure.

B. Dry heat

C. Convection current in water molecules.

D. Tyndallisation.

Correct Answer » B Explanation

Ans:B. Dry heat.

The instrument shown in the picture above represents hot air oven.

Hot air ovens .

Sterilization

• It is the process of killing all microorganisms (bacterial, viral, and fungal) with the use of either physical or chemical agents.

1. Sterilization by heat:

Sterilization by Moist Heat

• Moist heat acts by denaturation and coagulation of protein, breakage of DNA strands, and loss of functional integrity of cell membrane.

• Sterilization at 100°C:Boiling/Steaming.

• Single exposure/Tydallization(Fractional Sterilization).

• Sterilization above 100°C: Autoclaving.

Sterilization by Dry Heat

• Mechanisms. (1) Protein denaturation, (2) Oxidative damage, (3) Toxic effect of elevated electrolyte (in absence of water).

• Dry heat at 160°C (holding temperature for one hour is required to kill the most resistant spores). The articles remain dry.

• Red heat,/Flaming/Sterilization by Hot Air

• Hot Air Oven (Sterilizer). It Is one of the most common method used for sterilization.

• Glass wares, swab sticks, all-glass syringes, powder and oily substances are sterilized in hot air oven. For sterilization, a temperature of 160°C is maintained (holding) for one hour. Spores are killed at this temperature. It leads to sterilization.

2. Chemical Sterilization:Ethylene Oxide,Nitrogen

• Dioxide,Ozone,Glutaraldehyde,Formaldehyde,Hydrogen peroxide,Peracetic acid.

3. Radiation Sterilization:Ionizing and non-ionising Radiation

Which type of Bacillus is used to test efficacy of sterilisation by an instrument shown below?

A. Bacillus anthracis.

B. Bacillus pumilis.

C. Bacillus stearothermophilus.

D. Coxiella burnetti.

Correct Answer » C Explanation

Ans:C. Bacillus stearothermophilus.

The instrument shown in the picture above is an autoclave.

Sterilization

• It is a process designed to kill all microbes.

• Autoclave uses moist heat for sterilization.

• Because we can’t actually test whether all microbes are killed during the sterilization process, the next best thing is to determine whether the process kills the most resistant microbe.

• Bacterial spores have been selected as the most resistant type of microbe, and provide the foundation for the process of sterilization.

• For various methods of sterilization following biological indicators are used :-

• For moist heat sterilization process, spores of suitable strains Bacillus stearothermophilus are commercially available as biological indicators and frequently employed.

• Other heat-resistant spore-forming microorganisms such as Clostridium sporogenes,Bacillus subtilis and Bacillus coagulans have also been used in the validation of moist heat sterilization processes.

A. Atrial repolarization

B. Atrial depolarization

C. Ventricular repolarization

D. Ventricular depolarization

Correct Answer » D Explanation

D i.e. Ventricular depolarization

• QRS complex (wave) reflects ventricular depolarization.

• QT interval (or period of electrical systole of ventricles) is closely correlated with the mean action potential duration of ventricular myocytes.

• Contraction of ventricles lasts from the beginning of Q wave (or R wave, if Q wave is absent) to the end of T wave: an interval k/a QT interval.

Normal Electrocardiogram (ECG):

P wave:

• P wave reflects atrial depolarization before atrial contraction begins.

• QRS complex (wave) reflects ventricular depolarization before contraction.

• In other words, QRS complex is caused by potentials generated when the depolarization wave spreads through the ventricles, but before ventricular contraction begins.

• Therefore, both P waves and QRS complex are depolarization waves.

T wave:

• T wave represents ventricular repolarization.

• It is caused by potentials generated as the ventricles recover from the state of depolarization.

• This process normally occurs 0.25- 0.35 seconds after depolarization in ventricular muscles.

• T wave is also k/a repolarization wave.

Other important points:

• Current flows from one part of ventricle to another part (and therefore to the surface of body) to produce ECG only when the muscles is partly polarized and partly depolarized.

• No ECG is recorded when the ventricular muscle is either completely polarized or completely depolarized.

• Depolarization must spread through the muscle before contraction of muscle can occur.

• So the P wave occurs at the beginning of contraction of atria and the QRS complex occurs at the beginning of contraction of ventricles.

• The ventricles remain contracted until after repolarization has occurred i.e. until after end of T wave.

• Atria repolarize about 0.15 to 0.20 seconds after termination of P wave i.e. approximately during QRS complex.

• Therefore atrial repolarization wave (atrial T wave) is usually masked by much larger QRS complex (of ventricular depolarization).

• Ventricular repolarization begins about 0.20 seconds after the beginning of depolarization (QRS complex) in some fibers and takes as long as 0.35 seconds in others.

• Thus, ventricular repolarization (T wave) is prolonged process extending over 0.15 second, but the voltage of T wave is lesser than the voltage of QRS complex, partly b/o its prolonged length.

P-Q or PR interval:

• The time between the beginning of P wave and the beginning of QRS complexis called PR interval (when Q wave is absent) or more precisely P­Q interval.

• It is a measure of the time from the onset of atrial activation (ie beginning of electrical excitation of atria) to the onset of ventricular activation (or excitation).

• The PR interval measures the time between the atrial and ventricular depolarization, including the physiological delay imposed by cells in AV junction area.

• PR interval is normally 0.16 second (0.12 – 0.20 second).

• It shortens as the heart rate increases.

QT interval:

• Period of electrical systole of ventricles) is closely correlated with the mean action potential duration of ventricular myocytes.

• Contraction of ventricles lasts from the beginning of Q wave (or R wave, if Q wave is absent) to the end of T wave: an interval k/a QT interval.

• Normally QT interval is 0.4 second, but is inversely related with the heart rate because the duration of myocardial cell action potential varies inversely with the heart rate.

• A heart rate related (corrected) QT interval (QTc) can be calculated as QT,[1—Z – R and normally is 0.44 second.

A. Pityriasis Versicolor

B. Pityriasis Alba

C. Vitiligo

D. Tinea Facei

Correct Answer » B Explanation

Ans:B. Pityriasis Alba.

PITYRIASIS ALBA

• Pityriasis alba appears as poorly marginated, light patches on pigmented skin .

• Sometimes there is fine superficial scaling – hence the term pityriasis.

• Many patients are children with atopic dermatitis elsewhere.

• Other provokers of pityriasis alba are bites, sunburn (even among the dark-skinned), mechanical irritation from scrubbing, or other forms of eczematous dermatitis.

Diagnosis:

• A workup, as follows, may be undertaken to exclude other causes of hypopigmentation:
  Wood’s light examination: May help in determining the presence of vitiligo, which will glow more brightly and have edges with sharper demarcation

• Potassium hydroxide (KOH) stain of a skin scraping: Will be positive if the patient has tinea versicolor (also called pityriasis versicolor), tinea faciei, or tinea corporis

• Skin biopsy: Not usually necessary or particularly helpful in establishing a diagnosis of pityriasis alba but may be indicated if a diagnosis of mycosis fungoides (cutaneous T-cell lymphoma) is a significant possibility.

• In vitiligo, the spots are much whiter, much more sharply marginated and always without scaling.

• Pityriasis versicolor is also more sharply marginated and is usually scaly. Sarcoidosis and leprosy should also be kept in mind.

Treatment:

• No treatment is required and the patches in time will settle.The redness, scale and itch if present may be managed with simple emollients and sometimes hydrocortisone, a weak steroid, is also used.

A. Mainstay of treatment is PUVA

B. May be associated with hypo/hyperthyroidism

C. Melanocytes are absent

D. All of the above

Correct Answer » D Explanation

Ans:D. All of the above.

Vitiligo is shown in the image.

VITILIGO

Vitiligo is a focal failure of pigmentation d/t genetically predisposed destruction of melanocytes by immunological mechanism. So a patch of vitiligo shows marked absence of melanocytes & melanin in epidermis .

Vitiligo is associated with the following autoimmune diseases :-

• Alopecia areata

• Diabetes mellitus

• Hyperthyroidism

• Hypothyroidism

• Pernicious anemia

• Addison disease

• Multiple endocrinopathy syndrome

Long standing vitiligo with leucotrichia (depigmented hair), acrofacial lesions and lesion on resistant area are indicators of poor prognosis for therapy.

Treatment includes topical steroidse (for localized,

In which condition,the following type of nail abnormality is seen?

A. Psoriasis

B. Eczema

C. Thyrotoxicosis

D. All of the above.

Correct Answer » D Explanation

Ans:D. All of the above.

Onycholysis

Onycholysis is distal separation of the nail plate from the underlying nail bed . It is associated with the following:

• Idiopathic

• Trauma, excessive manicuring

• Infection: especially fungal

• Skin disease: psoriasis, contact dermatitis,eczema

• Impaired peripheral circulation e.g. Raynaud’s

• Systemic disease: hyper- and hypothyroidism, reactive arthritis, porphyria cutanea tarda

• Sometimes a reaction to detergents (e.g. washing dishes with bare hands, using detergent-based shampoos or soaps).

• Patients with hepatocellular dysfunction may develop hair-thinning or hair loss and nail changes such as clubbing, leukonychia (whitening), or onycholysis, affecting the nails of the hands and feet.

In which condition,the following type of nail abnormality is seen?

A. Psoriasis

B. Lichen Planus

C. Alopecia Areata

D. All of the above

Correct Answer » D Explanation

Ans:D. All of the above.

Pitting of the nail is seen in the image.

PITTING OF THE NAILS

Nail pitting — small punctate depressions — are caused by nail matrix inflammation, which can be the result of:

• Psoriasis (random appearance of pits) .

• Alopecia areata (geometric rippled grid) ;

• Eczema; and

• Lichen planus.

In which condition,the following type of nail abnormality is seen?

A. Lichen Planus

B. Lichen Planus

C. Eczema

D. Acne Vulgaris

Correct Answer » A Explanation

Ans:A. Lichen Planus.

Onychorrhexis is the presence of longitudinal striations or ridges .. It can simply be a sign of advanced age but it can also occur with the following:

• Rheumatoid arthritis;

• Peripheral vascular disease;

• Lichen planus; and

• Darier’s disease (striations are red/white).

Central ridges can be caused by:

• Iron deficiency;

• Folic acid deficiency; and

• Protein deficiency.

In which condition,the following type of nail abnormality is seen?

A. Iron Deficiency Anemia

B. Sickle Cell Anemia

C. Megaloblastic Anemia

D. All of the above

Correct Answer » A Explanation

Ans:A. Iron Deficiency Anemia.

Koilonychia is shown in the image.

KOILONYCHIA

• Koilonychia , also known as spoon nails,a nail disease that can be a sign of hypochromic anemia, especially iron-deficiency anemia” .

• It refers to abnormally thin nails which have lost their convexity, becoming flat or even concave in shape.

• In a sense, koilonychia is the opposite of nail clubbing. In early stages nails may be brittle and chip or break easily.

• Koilonychia is associated with Plummer-Vinson syndrome and iron deficiency anemia.

It is also seen in:

• Diabetes mellitus;

• Protein deficiency, especially in sulfur-containing amino acids (cysteine or methionine);

• Exposure to petroleum-based solvents;

• Systemic lupus erythematosus; and