X-Message-Number: 24536
From: "Basie" <>
Subject: It is all about pressure 
Date: Thu, 19 Aug 2004 16:16:56 -0400

It is all about pressure. Even this document does not show what really
happens. But it is not about the cutting or the  "hamburger" effect.
Basie

See:http://www.2rui.com/html/cryopres.html

<As the temperature drops to -15 degrees centigrade, ice crystals form
within the cells and cause the cell membrane to explode>

Cryosurgical Ablation of the Prostate


Principles of the technique and the Grant/Riemenschneider experience,
October 2001 - March 2003



More information on Cryosurgery and prostate cancer available here

Definition of Cryotherapy - Invitro freezing and destruction of tissue that
can be applied and controlled precisely to produce a predictable zone of
tissue death that will destroy the "target lesion" (bad cells) as well as an
appropriate margin of surrounding tissue (J Surg Oncology, 1966; 256-264).

The third generation cryo-probe is a needle that has fantastic engineering
built into it. The caliber of the cryo probe is the same as needles that are
used to draw blood from a patient's arm when obtaining lab work. This cryo
probe has the ability to produce very cold temperatures and results in the
formation of "lethal ice". This probe also has the capacity to transmit heat
through the probe to stop the growth of the ice ball.

The mechanism by which these cold temperatures kill the target cells occurs
in three ways. First, the extracellular ice formation occurs at -7 degrees
centigrade. Second, ice crystals form between the cells and in so doing,
dehydrates the space which draws water from the cells causing the cells to
dehydrate. Three, the dehydration destroys or severely injures the
biological mechanism of the cell that keeps it alive.



As the temperature drops to -15 degrees centigrade, ice crystals form within
the cells and cause the cell membrane to explode.



As this process continues, the blood that flows through the vessels within
these tissues coagulates and the blood supply to these tissues is cut off,
eliminating adequate sources of oxygen and nutrition to the target cells.



The history of cryosurgery tells us that the early cryo probes were very
large and the cooling agent was liquid nitrogen. This agent is very
effective resulting in very cold temperatures and hard freezes. These probes
had no warming element and therefore, the freeze was very difficult to
control. The second-generation cryo probes were smaller and used Argon gas
as the cryogen, was more controllable than liquid nitrogen and includes a
heating element that is based on the expansion of Helium gas being pumped
through the probe at the right time.

The third generation cryo probe uses Argon for freezing and Helium for
heating. It is much smaller than the second generation probes, it is a
17-gage needle. This needle is so small it can be placed with pinpoint
accuracy at the time of freeze and will result in the cell death cycle which
occurs at the target tissue.

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