#pathologists

Virtual Pathologist

Image identification by machine learning models is a major application of artificial intelligence (AI). And, with ever-improving capabilities, the use of these models for medical diagnostics and research is becoming more commonplace. Doctors analysing X-rays and mammograms, for instance, are already being assisted by AI technology, and models trained to identify signs of disease in tissue sections are also being developed to help histopathologists. The models are trained with microscope images annotated by humans – the image, for example, shows a section of rat testis with signs of tubule atrophy (pale blue shapes) with other coloured shapes indicating normal tubules and structures. Once trained, the models are tasked with categorising unannotated datasets. The latest iteration of this technology was able to identify disease in testis, ovary, prostate and kidney samples with exceptional speed and high accuracy – in some cases finding signs of disease that even trained human pathologists had missed.

Written by Ruth Williams

Image from work by Colin Greeley and colleagues

Center for Reproductive Biology, School of Biological Sciences and the School of Electrical Engineering and Computer Science Washington State University, Pullman, WA, USA

Image originally published with a Creative Commons Attribution – NonCommercial – NoDerivs (CC BY-NC-ND 4.0)

Published in Scientific Reports, November 2024

🏈 Super ‘Bowel’ Sunday LVII💩

This football-shaped egg is the spawn of the female whip worm Trichuris trichiura.

They can be found in water contaminated by feces or in delicious half-time hotdogs 🌭 handled by unsanitary fingers. Once ingested it makes its way into your intestines and after about 3 months will hatch into a worm.

Once mature, the worm burrows her head and mouth parts into the delicate and comfortable mucosa of your intestines to feed. It is here that she will trigger an inflammatory response and causes bouts of abdominal pain with plenty of (sometimes bloody) diarrhea. A disease called trichuriasis.

While she is feeding she dangles her vulva into the lumen of your intestine and has sex with as many nearby male worms as possible.

Our little parasite now becomes a momma and starts firing out somewhere between 2,000-10,000 of these little eggs…

Per day!

This life of feeding and egg-laying, if left untreated, can last for the lifespan of a roundworm which can be around 5 years… that’s a very busy worm and lots of eggs.

All those eggs get flushed out of your body with your bloody diarrhea and, depending on where you live, ‘touchdown’ in the local water supply or back on that hotdog ready to be ingested once again and the whole process starts over.

me: uhhhhhhhhhhhhh I don’t think so but. I’m really not very good at identifying that yet so there probably is, I’m not sure

🍪🥚 Cookie Monster Ovary 🥚🍪

Today's ihearthisto is brought to you by the letter O for Oocyte!

i♡histo

This is image shows a high magnification view of a slice through an ovary.

You are looking at four tiny primordial follicles (the cookies above Cookie Monster's head) located in the outer cortex of the ovary. Each of these follicles contains a single dormant, immature egg (a primary oocyte) that is halted in the the first phase of meiosis (prophase I). Eventually these follicles will be recruited to enter the maturation cycle that, against all the odds, could see them develop into an embryo.

Cookie monster himself is a larger multilaminar primary follicle (the cookie in his mouth is the nucleus of the oocyte within the follicle). This type of follicle has already been recruited and it's follicular cells are dividing and differentiating. The oocyte within it though is still halted in prophase I of meiosis.

🐱 Kitty Liver 🐱

Check meowt!

I'm a purrfect hepatic vein surrounded by hepatic lobules!

i♡histo

This is a hematoxylin and eosin stained slice through a liver that was injected with carbon/ink prior to fixation.

The liver is compose of numerous roughly hexagonal shaped lobules. Each lobule has a venule at its center (the central vein; top right) and a series of hepatic triads at its periphery. A triad is a collection of three structures - in this case branches of the hepatic artery, hepatic portal vein and hepatic duct.

Blood in the hepatic artery (oxygenated) and hepatic portal vein (rich in nutrients absorbed from the intestines) travels in sinusoids (the many narrow white spaces in this image) towards the central vein of each lobule. On its way through the sinusoids the blood is processed by the the many hepatocytes that line this region (the pink cells). Within the sinusoids reside many liver macrophages (Kupffer cells) that phagocytose debris traveling through sinusoids. Normally these cells are invisible in standard H&E preparations but recall that this tissue was injected with ink! The ink was phagocytosed by the macrophages filling their cytoplasm with carbon so that they are now visible as black cells in the sinusoids.

Once the blood enters the central vein of each hepatic lobule they drain into the hepatic veins (kitty!) until the blood reaches the inferior venal cava.

In this way all blood, rich in raw nutrients and toxins absorbed from the GI tract is processed by the liver before it enters the systemic circulation!

⭐ Patrick Star in a Sperm Tube 🍒

My favorite Patrick in honor of #stpaddysday☘️ 

Some say that Patrick Star and the male reproductive tract are fairly similar... but if you look closely there's actually a vas deferens.

i♡histo

This image shows the tube through which spermatozoa travel during ejaculation. It is called the vas deferens (ductus deferens). 

Histologically it is unique because of its unique pseudostratified epithelium (surrounding Patrick...check out the unique regular beaded appearance of the basal cells in this epithelium) and its triple-layered smooth muscle wall - so thick you can actually palpate it within the spermatic cord within the scrotum. Patrick is actually within the empty space of the lumen of the tube (where the sperm travels). 

Spermatozoa are produced in the seminiferous tubules of the testes and travel to the epididymis where they complete the maturation process. During ejaculation, a peristaltic wave of strong muscular contractions propel the sperm from the epididymis and into the vas deferens. This wave of peristalsis continues along the triple-thick muscle wall of the vas deferens eventually pushing the sperm out into the urethra. From here they have enough momentum to travel along the length of the penis before exiting exit the tube at the external urethral meatus (the fancy anatomical name for the hole at the end of the penis).

But sperm are not the only stuff that is ejaculated... at the same time as the sperm is moving along this pathway, the smooth muscle surrounding a number of glands also contracts which pushes their secretions into the urethra too at the same moment that the sperm is moving through it. These include secretions from the seminal vesicles (seminal fluid), prostate gland (prostatic fluid) and bulbourethral glands.

The final concoction that is ejaculated is actually a combination of sperm and all of these extra sperm-nourishing secretions and collectively it is known as semen.

Which brings us back to where we started with this sea-man - Patrick Star!

🍥 Meet the Hassalls 🍥

The many faces of type VI thymic epithelial reticular cells

i❤️histo

The thymus is a primary lymphoid organ: a site where immature T-cells (a type of lymphocyte) are 'educated'.

Thymic education is a process that ensures naive, newborn T-cells only recognize MHC (major histocompatability complex) and non-self (foreign) antigen. Cells that do not pass a series of 'educational tests' in the thymus are destroyed. This makes sure that all mature T-cells that enter the circulation will not recognize our own cells and proteins as foreign - thus avoiding the triggering of an autoimmune response.

Epithelioreticular cells (ERCs) are important cells in this education process There are six different types given roman numeral names I-VI.

Type I ERCs form the thymus-blood barrier between our blood that is filled with self/non-self antigen and the naive T-cells in the thymus awaiting education.

Type II ERCs are the level 1 educators. They present MHC-I/II proteins to naive T-cells to see if they can identify them. The T-cells that identify them pass this first test (positive selection) and those that don't are eliminated. Most T-cells fail this test and are eliminated.

Type III and Type IV ERCs lie most likely allow passage of selected T-cells to the next ERCs.

Type V ERCs are the level 2 educators.They have long spindly legs covered with fragments of self antigen. If a T-cell binds one of these proteins it is eliminated from circulation and only those that do not bind reach maturity (negative selection).