Osteoblasts!

So, I opened up my good old Wheater's histology textbook (Young et al. 2006) and began reading up on osteoblasts. I was reminded that osteoblasts pretty much lay on top of mineralized bone matrix. It forms sort of a coating along the entire inner surface.

What caught my attention was how the authors described the process of laying down new bone. I made a quick sketch of this process in figure 1. The authors describe the osteoblasts as being spindle shaped when they are inactive. This is shown in the first panel. When laying down osteoid or new bone, the osteoblasts enlarge into cuboidal shaped cells, as shown in the third panel. Finally, they slowly return to their spindle-shaped forms as they lay down calcium hydroxyapatite (this is what hardens the newly laid osteoid).

FIGURE 1

Thinking about what they said visually and spatially, however, I found it slightly confusing. What do they mean by spindle-shaped. Are they referring to the appearance of the osteoblasts in histological slides? That they appear to be a thin spindle from a lateral view? If this is so, are they actually squamous cells cuts in sections? Or are they like muscle fibres, elongated cells? If they are, then how do they become cuboidal in nature? Do they increase in mass laterally and vertically?

Note that the following illustrations assume that osteoblasts are squamous and increase in height perpendicular to the bone surface. But with this assumption, there came another problem! Does an osteoblast maintain a generally constant volume when inactive and active (Figure 2b)? This question is not addressed in the textbook, and I'm pretty sure the prof didn't mention it either... If the answer if no... then would a lateral view appear like Figure 2a?

FIGURE 2

Such questions may appear to be relatively irrelevant, mundane, or trivial I suppose. For sure, I never thought to analyze osteoblast like this when I first learn of them. But, now that I plan on animating such cells, it's suddenly a huge deal! Well, maybe not super huge, but I would venture to say that such a consideration would have an immense impact on the credibility or captivity of an animatic piece. Could these sketches (Figure 3) provide any insight into the actual structure or functionality of osteoblasts that I have not yet figured out...? Most likely not, someone's probably done it. But, I'm sure it will come in handy when it comes down to the modeling and 3D interactivity.

FIGURE 3

So Figure 4 here is a redraw of my first comic strip (Figure 1) with consideration of volume and overlap, as seen from a lateral view.

FIGURE 6

Bones!

(Yay for multiple posts in a short timespan...)

After the first committee meeting, Marc was talking about how difficult it is to render bone realistically. Particularly since it involves a complex matrix of trabeculae, interconnecting here, there, and everywhere! And how to create an enclosed environment that actually feels... well, enclosed! And if it's enclosed, then how does one pan in and out, move in and out of cells, zoom in and out, etc? And to make it visual pleasing as well!?

I think that I'm going to have to look into bone formation and histology a little more before I start rendering (after tackle the science and proposal of course! priorities!)

But in the meantime, here's a cool video of osteoclasts! Notice the bubbling lava fungi (vesicle formation at 5:00) and the jellyfish/sea-sponge (4:25) scenes!!!

Some thoughts on scope

A very generalized proposal... VERY preliminary!

"My masters research project will be a visualization of bone cancer and pain. Particularly, I will be looking closely at events that occur at the cellular level that lead to increased pain perception in patients. I will look at how tumour growth stimulates mechanoreceptors, how factors released by tumour and host cells activate chemoreceptors, and how decreased pH in the tumour environment increases nociceptor sensitivity. I will also touch upon the more long-term changes that occur to the primary afferent neurons. In consideration of the intended complexity of the project, I will likely not go further than the level of the spinal segment.

I intend for the animatic to be usable as a teaching aid that will be geared towards university students and the scientific community. Currently, I plan to use a combination of 2D and 3D rendered animation sequences. I believe that a sequence of 2D images may be sufficient to introduce the piece and effectively explain the more gross anatomical parts of the science than. 3D animations will be use to navigate through the tumour environment and visualize the many interactions occurring at this level."

Round table 1

In attendance: Linda, Marc, Philippe, Nicolas, Me

For my first committee meeting, aside form introductions, we just talked science mainly. I got to hear Nicolas and Philippe's story on bone cancer. Btw, this is the article I had read going in:

2002, Mantyh et al. Molecular mechanisms of cancer pain.

At the end of the meeting, the first thing that I realized was, there was perhaps too much material. I must say that I would love to animate anything and everything (there were some cool visuals playing out in my head during the meeting), but as Marc and Linda kindly reminded me, the average length of a 3D visualization project is 3-4 minutes, narration is limited (due to time) to aproximately 250 words? In either case, there's not enough time!

Anyways, for this entry, here's the story. Keep in mind, that from now on, we are going to deconstruct!!!

THE SCIENTIFIC CONTENT (REALLY BRIEFLY)

Bone cancer is often a metastasis of breast cancer. We are going to set the scene in long bone, say the femur. In bone cancer, as with other tumours, the mechanisms of pain perception is altered. When is comes to nociception, you have tumour growth that can act on mechanoreceptors. We have a number of factors released by dying cells, tumour cells, and even our own inflammatory cells, that act on a host of cell surface receptors. To make things worse, findings show that decreased pH (as in tumour environments) can decrease the activation threshold of many receptors and ion channels. Also, osteoclast and osteoblast are around to complicate the picture too! Then, spinal cord, and reflex arcs, and even CNS! Thanks to our wonderful nervous system and its plasticity, when there are tumours and continuous aggravation of pain receptors, the neurochemistry of our nervous system gets altered. There are alterations in the lamina of the dorsal horns. Inhibitory neurons become excitatory. And the chaos continues.

So obviously, there is a lot of stuff to show, and to visualize any of these elements at a level that is appropriate for graduate level students, would require signficant amounts of time.

The first entry...

For my first entry, I feel that I need to explain to readers (but for my own sake really) that this blog is meant to be informal and colloquial.

BASICS

For my second year at Biomedical Communications, I will be in the 3D visualization stream. Linda Wilson-Pauwels, my supervisor, offered me a project on pain visualization, curtesy of CIHR. Marc Dryer is my second voting member. My scientific content advisors will be Philippe Sarret and Nicolas Beaudet from Sherbrooke.

TOPIC

Bone cancer related pain!