Identification of Other Biological Fluids: Vaginal Secretions, Menstrual Blood, Sweat, and Vomit

What methods can be used ton identify vaginal secretions?

Microscopic examination, biochemical assays, microbial analysis, molecular techniques, and spectroscopic methods

Microscopic examination of vaginal secretions

identification of glycogenated epithelial cells

Squamous mucosa

Stratified squamous epithelium

Submucosa

Connective tissue and capillaries

Muscularis

Smooth muscle

Basal layer

Proliferative basal cells

Intermediate layer

Flattened cells with compressed nuclei

Superficial layer

Fully differentiated, glycogenated cells

glycogenated cells

maintain vaginal health (most commonly collected)

Lugol's Iodine Staining

Iodine reacts with glycogen to form a dark brown complex

Periodic Acid-Schiff (PAS) Method

Stains the cytoplasm of the cell magenta and the nuclei purple

Dane's Staining

Stains vaginal cells bright orange with an orange nuclei (skin cells: red/orange; buccal cells: orange-pink with a red nuclei)

Microbial Analysis

identification of Lactobacillus in vaginal fluid (L. iners, L. crispatus, L. gasseri, and L.jensenii)

Lactobacillus

maintains a low pH and restricts pathogenic growth in vagina

What is the limitation of using Lactobacillus to identify vaginal secretions?

Overlaps with microbiota in urine and semen (there are still some that are unique to men and women)

Tissue-Specific Gene Expression

detection of vaginal-specific mRNAs and miRNAs (confirmatory)

Menstruation

Periodic discharge of blood and endometrial lining from the uterus

What are the three layers of the uterus?

1. perimetrium
2. myometrium
3. endometrium

Uterine Cycle

The cyclic changes in the endometrium (uterine lining)

Functionalis

The top layer of the endometrium that is shed during menstruation

Basalis

The bottom layer of the endometrium that remains intact during menstruation and regenerates the functionalis

What are the three phases of menstruation?

1. Menstrual phase (shedding of functionalis)
2. Proliferative phase (regeneration of functionalis and spiral arteries)
3. Secretory phase (further development and coiling of spiral arteries)

Uterine Endometrial Hemostasis

Occurs after the shedding of the endometrium.
- Platelets form plugs at the injury site, and the coagulation cascade produces thrombin.
- Fibrin forms clots, leading to cessation of bleeding.
- Balance between clot formation and dissolution ensures tissue removal and infection prevention.

What methods are used to identify menstrual blood?

D-dimer assay, Lactate Dehydrogenase (LDH) assay, and RNA-based assays

D-dimer assay for menstrual blood

Differentiates mensural blood from peripheral blood by the formation of a degradation product from fibrinolysis

How is the degradation product from D-dimer assay is visualized/identified?

ELISA, aggulation, and immunochromatographic assays

Lactate Dehydrogenase (LDH) Assay

Identifies the types of LDH (enzyme involved in glycolysis) found in mensural blood through electrophoresis

What types of LDH are common in mentsrual blood?

LDH4 and LDH5 (LDH1, LDH2, and LDH3 are common in peripheral blood)

Matrix metalloproteinase (MMP) genes

produce the enzyme that breaks down tissue during menstruation by degrading the extracellular matrix

Eccrine Glands

Sweat glands found all over the body that regulate body temperature.

When do eccrine glands produce watery sweat?

During exercise and when the body is hot.

Apocrine Glands

Sweat gland located ONLY on the underarms and genitalia

When do apocrine glands produce sweat?

produce oily, odorous sweat due to emotional stress

What is sweat composed of?

Water, minerals, lactate, urea, and some other substances

What assays can be used to identify sweat?

Elemental analysis & Raman spectroscopy (not sweat-specific) and ELISA (dermcidin - specific biomarker in sweat)

vomiting

Involves the contraction of the diaphragm and stomach that forces the contents of the stomach upward

What is the composition of vomit?

Gastric fluid (acidic stomach contents) and stomach fluid (hydrochloric acid, mucus, enzymes, and hormones)

What assay can be used to identify vomit?

pepsin-proteolytic assay

What does the Pepsin-Proteolytic Assay detect?

Pepsin activity

How is pepsin activity detected in the Pepsin-Proteolytic Assay?

Fibrin blue breaks down in the presence of pepsin, forming a blue ring

Is the blue ring formed in the Pepsin-Proteolytic Assay human-specific?

No, it is vomit-specific