Health and science platform

28/01/2026

28/01/2026

🟣 Normal Newborn Skin Findings (First Days of Life)

These are physiologic neonatal skin changes seen in healthy newborns and require no treatment.

🟣 Vernix Caseosa

Definition:
→ Thick, white, cheesy material covering newborn skin at birth.

Composition:
→ Sebaceous secretions + desquamated epithelial cells.

Functions:
→ Acts as skin barrier
→ Prevents transepidermal water loss
→ Has antimicrobial properties
→ Provides lubrication during delivery

Clinical points:
→ Common in term babies
→ More abundant in preterm infants
→ Disappears spontaneously in few days

🟣 Lanugo

Definition:
→ Fine, soft, non-pigmented fetal hair.

Distribution:
→ Shoulders, back, forehead, ears.

Clinical points:
→ More prominent in premature infants
→ Normally sheds within first 2–4 weeks of life
→ No treatment required

🟣 Congenital Dermal Melanocytosis (Mongolian Spots)

Definition:
→ Blue-gray macular pigmentation due to dermal melanocyte entrapment.

Common sites:
→ Lumbosacral region
→ Buttocks

Characteristics:
→ Flat
→ Non-tender
→ Present at birth
→ Not raised

Epidemiology:
→ Common in Asian, African, Hispanic populations.

Course:
→ Gradually fades during early childhood.

Exam pearl:
→ Must be differentiated from bruising / child abuse.

🟣 Acrocyanosis

Definition:
→ Bluish discoloration of hands and feet with normal pink lips and tongue.

Cause:
→ Peripheral vasoconstriction due to immature neonatal circulation.

Timing:
→ First 24–48 hours after birth
→ May recur with cold exposure.

Important distinction:
→ Central cyanosis = lips/tongue blue → pathological
→ Acrocyanosis = peripheral only → physiologic

🟣 Physiologic Desquamation

Definition:
→ Peeling or scaling of newborn skin.

Sites:
→ Palms and soles commonly.

Cause:
→ Adaptation from amniotic fluid environment to dry air.

Timing:
→ Appears in first few days of life.

Course:
→ Resolves spontaneously within weeks.

06/01/2026

Harlequin Ichthyosis – A Rare and Challenging Congenital Disorder
Harlequin ichthyosis (HI) is the most severe form of autosomal recessive congenital ichthyosis, with an incidence of approximately 1 in 300,000 live births.

Genetic Basis
Caused by biallelic mutations in the ABCA12 gene, which impairs lipid transport in keratinocytes, leading to defective skin barrier formation.

Clinical Presentation at Birth
- Thick, rigid, plate-like hyperkeratotic skin with deep erythematous fissures (“harlequin” appearance)
- Severe ectropion (everted eyelids) and eclabium (everted lips)
- Restricted limb movement and joint contractures
- Flattened ears and nose
- High risk of: – Transcutaneous fluid and heat loss – Sepsis (due to barrier disruption) – Respiratory distress (chest restriction or aspiration)

Immediate Neonatal Management
Multidisciplinary care is essential:
- Humidified incubator to prevent dehydration
- Gentle mechanical debridement and frequent application of emollients
- Ophthalmic lubricants for ectropion protection
- Infection surveillance and early antibiotics if needed
- Nutritional support (high-calorie feeds)
- Oral retinoids (e.g., acitretin) often initiated early to promote shedding of hyperkeratotic plates

Long-Term Care
- Ongoing intensive emollient therapy
- Multidisciplinary follow-up (dermatology, ophthalmology, physiotherapy, psychology)
- Risk of recurrent infections, overheating, and growth issues

Prognosis
Historically fatal in the neonatal period, survival has dramatically improved with modern intensive care — many individuals now live into adulthood with good quality of life.

Key Nursing Role
Compassionate, meticulous skin care and family education are pivotal. Support parents through the initial shock and empower them for lifelong management.
Early diagnosis (possible via prenatal ultrasound or genetic testing) and prompt specialised care save lives.

# keybet medical biochemist

06/01/2026

❇️ Mechanisms of Vascular Occlusion & Ischemia

Reduced tissue perfusion can occur due to intraluminal obstruction, vessel wall pathology, or altered blood properties. The image illustrates 8 key mechanisms.

A. Thrombosis

→ Definition: Formation of a blood clot in situ within a vessel.
→ Pathophysiology: Endothelial injury + stasis + hypercoagulability (Virchow triad).
→ Effect: Progressive luminal narrowing or complete occlusion.
→ Examples:
→ Myocardial infarction (coronary thrombosis)
→ Ischemic stroke (carotid or cerebral artery thrombosis)
→ Deep vein thrombosis

B. Embolism

→ Definition: Occlusion of a vessel by material formed elsewhere and transported by blood.
→ Types:
→ Thromboembolus (most common)
→ Fat embolus
→ Air embolus
→ Septic embolus
→ Effect: Sudden vessel blockage → acute ischemia.
→ Examples:
→ Pulmonary embolism
→ Cardioembolic stroke (atrial fibrillation)

C. Vasospasm

→ Definition: Transient, reversible constriction of vascular smooth muscle.
→ Mechanism: Increased calcium influx or endothelial dysfunction.
→ Effect: Reduced blood flow without structural blockage.
→ Examples:
→ Prinzmetal (variant) angina
→ Cerebral vasospasm after subarachnoid hemorrhage
→ Raynaud phenomenon

D. Atheroma (Atherosclerosis)

→ Definition: Lipid-rich plaque formation in the intima of arteries.
→ Components:
→ Lipid core
→ Fibrous cap
→ Inflammatory cells
→ Effect: Chronic luminal narrowing and reduced perfusion; plaque rupture may trigger thrombosis.
→ Common sites:
→ Coronary arteries
→ Carotid bifurcation
→ Circle of Willis

E. External Compression

→ Definition: Vessel narrowing due to pressure from outside the vessel.
→ Causes:
→ Tumors
→ Hematomas
→ Abscesses
→ Edema
→ Effect: Reduced or obstructed blood flow.
→ Examples:
→ Compartment syndrome
→ Tumor-related vascular compression

F. Vasculitis

→ Definition: Inflammation of blood vessel walls.
→ Mechanism: Immune-mediated endothelial injury → wall thickening, thrombosis, or aneurysm.
→ Effect: Lumin

31/12/2025

Common headache Types:

Stress Headache (Tension-type) → Pain forms a tight band around the forehead and back of the head
→ Dull, aching sensation
→ Often triggered by stress, poor posture, or fatigue

Migraine → Intense, throbbing pain on one side of the head
→ Often associated with nausea, sensitivity to light/sound
→ Can have visual auras before the headache starts

Hypertension Headache → Pain usually at the back of the head or neck
→ Often pulsating and occurs during high blood pressure spikes
→ May worsen with physical activity

Cluster Headache → Severe pain around one eye
→ Occurs in clusters (repeated over weeks/months)
→ May cause tearing, nasal congestion on the same side

Sinus Headache → Pain and pressure around the forehead, cheeks, and nose
→ Often worsens with movement or bending down
→ Usually accompanied by sinus infection symptoms (e.g., nasal congestion)

Post-Traumatic Headache → Develops after a head injury
→ Pain can be localized or widespread
→ May be accompanied by dizziness or memory issues

TMJ Headache → Pain near the temples or jaw joint
→ Associated with jaw clenching, grinding, or TMJ disorder
→ Can radiate to ear or neck

Exertion Headache → Triggered by physical activity (exercise, coughing, s*x)
→ Throbbing pain often at the front or sides of the head
→ Usually short-lasting but intense

Thunderclap Headache → Sudden, severe headache that reaches peak intensity within seconds
→ Medical emergency—can indicate bleeding in the brain or aneurysm
→ Requires immediate medical attention

31/12/2025

31/12/2025

🧬 Amino Acids: Essential & Non-Essential Explained

Amino acids are the building blocks of proteins, crucial for growth, metabolism, tissue repair, immunity, and brain function. This visual map highlights essential amino acids (obtained from diet) and non-essential amino acids (synthesized by the body) along with their key biological roles—perfect for quick revision and concept clarity.

29/12/2025

ECM Remodelling in the Metastatic Cascade👇

✅Intravasation and survival in circulation
At the primary tumour site, intense angiogenesis and high matrix metalloproteinase (MMP) activity disrupt normal vascular architecture. This leaky and disorganized vasculature allows tumour cells to intravasate and enter the bloodstream.

Once in circulation, tumour cells become circulating tumour cells (CTCs). Some CTCs secrete or associate with extracellular matrix (ECM) components, which can shield them from immune recognition and enhance their survival under shear stress.

✅Interactions with neutrophils and NETs
CTCs do not travel alone in the circulation. They can form matrix-like interactions with neutrophil extracellular traps (NETs) and NETotic neutrophils.

These interactions are mediated by integrins expressed on both CTCs and neutrophils. NET–CTC binding promotes CTC survival, clustering, and arrest within the vasculature, increasing the likelihood of metastatic seeding.

✅Endothelial ECM remodelling and extravasation
At distant organs, endothelial cells actively participate in ECM remodelling. They deposit and assemble fibrillar fibronectin on the endothelial surface, which promotes adhesion of CTCs to the vessel wall.

Elevated MMP activity further increases vascular permeability. This leaky vasculature facilitates CTC extravasation into the surrounding tissue, marking a critical step in metastatic colonization.

✅Formation of the pre-metastatic niche
Primary tumours release a wide range of factors into the circulation, including growth factors, MMPs, lysyl oxidase (LOX), ECM proteins such as fibronectin, and tumour-derived exosomes.

These signals act at distant organs to establish a pre-metastatic niche. This niche primes the local tissue environment to become permissive for incoming tumour cells even before their arrival.

✅Stromal activation and ECM deposition
Within the pre-metastatic niche, stromal cells respond to tumour-derived factors and become activated.

28/12/2025

❇️ Common Facial Skin Conditions:

🩺 Acne Vulgaris
→ Chronic inflammatory disease of pilosebaceous units
→ Presence of comedones, papules, and pustules on forehead and central face
→ Common in oily skin areas due to increased sebum and follicular blockage

🩺 Rosacea
→ Chronic inflammatory facial disorder
→ Central facial erythema involving nose and medial cheeks
→ Associated flushing and inflammatory papules
→ Absence of comedones helps differentiate from acne

🩺 Seborrheic Dermatitis
→ Inflammatory condition linked to Malassezia yeast
→ Erythema with greasy yellowish scales
→ Commonly affects eyebrows, nasolabial folds, and hairline

🩺 Atopic Dermatitis (Eczema)
→ Chronic pruritic inflammatory skin disease
→ Dry, erythematous patches around periorbital area and cheeks
→ Skin barrier dysfunction plays a key role

🩺 Contact Dermatitis
→ Type IV delayed hypersensitivity reaction
→ Localized erythema, scaling, and irritation
→ Seen on cheek area corresponding to cosmetic or topical exposure

🩺 Melasma
→ Acquired hyperpigmentation disorder
→ Symmetric brown macules on cheeks and upper lip region
→ Triggered by UV exposure, hormones, or pregnancy

🩺 Psoriasis (Facial Involvement)
→ Immune-mediated inflammatory disorder
→ Well-demarcated erythematous plaque near hairline
→ May show fine scaling on facial margins

🩺 Herpes Simplex Infection
→ Viral infection caused by HSV-1
→ Grouped vesicles on erythematous base near lips
→ Lesions may rupture and crust

🩺 Tinea Faciei
→ Superficial dermatophyte fungal infection of the face
→ Annular erythematous plaque with raised scaly border
→ Central clearing is characteristic

🩺 Post-Inflammatory Hyperpigmentation (PIH)
→ Residual hyperpigmentation following inflammation or injury
→ Appears as dark macules on cheeks and forehead
→ More common in darker skin tones

🩺 Lentigines
→ Benign hyperpigmented macules
→ Caused by chronic sun exposure
→ Common on cheeks and sun-exposed facial areas

🩺 Actinic Keratosis
→ Premalignan

28/12/2025

Biochemist Kary Mullis, discovered the polymerase chain reaction (PCR) while driving a route well known to him at night.

His thoughts wandered, the pieces of a puzzle he had been thinking about fell into place and the rest is history.

Mullis was awarded the chemistry prize for his invention of the PCR method in which a small amount of DNA can be copied in large quantities over a short time.

By applying heat, the DNA molecule's two strands are separated and the DNA building blocks that have been added are bonded to each strand. With the help of the enzyme DNA polymerase, new DNA chains are formed and the process can then be repeated. PCR has been of major importance in both medical research and forensic science.

Read more about how Mullis discovered PCR: https://bit.ly/2F53qwS

28/12/2025

🧬 Endoplasmic Reticulum (ER): Structure, Types & Key Functions

The endoplasmic reticulum (ER) is an essential intracellular membrane network involved in protein and lipid synthesis. Rough ER (RER) supports protein production and secretion, while Smooth ER (SER) plays a key role in lipid synthesis, detoxification, and calcium storage—together ensuring efficient cellular metabolism and transport.