Biopsy

A biopsy (in Greek: βίος life and όψη look/appearance) is a medical test involving the removal of cells or tissues for examination. It is the removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically. When an entire lump or suspicious area is removed, the procedure is called an excisional biopsy. When only a sample of tissue is removed with preservation of the histological architecture of the tissue's cells, the procedure is called an incisional biopsy or core biopsy. When a sample of tissue or fluid is removed with a needle in such a way that cells are removed without preserving the histological architecture of the tissue cells, the procedure is called a needle aspiration biopsy.




oral lesions whose diagnosis can be made relying on data gathered during the history and/or physical examination, but there are others where histopathological studies are needed to confirm the presumed clinical diagnosis.

Biopsy is a surgical procedure to obtain tissue from a living organism for its microscopical examination, usually to perform a diagnosis





Objectives

The aim of the biopsy is to:

• define a lesion on the basis of its histopathological aspect;

• to establish a prognosis in malignant or premalignant lesions;

• facilitate the prescription of specific treatment;

• contribute to the assessment of the efficacy of the treatment;

• act as a document with medical-legal value.



Indications

Biopsy is indicated for diagnostic confirmation of suspected malignant lesions, precancerous lesions such as leukoplakias or erythroplakias and chronic ulcerations of unknown cause. It is also indicated for the histological confirmation of certain systemic disorders (Fig.1) and is recommended for apparently inflammatory lesions that do not improve within two weeks of removal of local irritants.

Other lesions that should also be biopsed include:

• lesions that interfere with oral function, such as fibrous hyperplasias and osseous lumps.

• lesions of unclear aetiology, particularly when associated with pain, paraesthesia or anaesthesia

• interstitial lesions in lingual, buccal or labial muscles

• radiolucent or radio-opaque osseous lesions.



When is oral biopsy not needed?

• There is no need to biopsy normal structures

• There is no need to biopsy irritative/traumatic lesions that respond to the removal of a presumed local irritant

• There is no need to biopsy inflammatory or infectious lesions that respond to specific local treatments, as pericoronitis, gingivitis or periodontal abscesses

• No incisional biopsies should be performed on suspected angiomatous lesions.



Types of biopsy

According to the procedures applied, oral biopsies can be classified by:

a) Features of the lesion:

• direct biopsy: when the lesion is located on the oral mucosa and can be easily accessed with a scalpel from the mucosal surface.

• indirect biopsy: when the lesion is covered by an apparently normal oral mucosa

b) Area of surgical removal:

• incisional biopsy: consists of the removal of a representative sample of the lesion and normal adjacent tissue in order to make a definitive diagnosis before treatment.

• excisional biopsy: is aimed at the complete surgical removal of the lesion for diagnostic and therapeutic purposes. This procedure is elective when the size and location of the lesion allows for a complete removal of the lesion and a wide margin of surrounding healthy tissue (Fig.2).

c) By the timing of the biopsy:

• Pre-operative

• Intra-operative

• Post-operative when aimed at checking the efficiency of a treatment.



General principles of oral biopsy

Before the procedure is undertaken, the characteristics of the lesion (size, shape, colour, texture, consistency, time of evolution, associated signs and symptoms, regional nodes) should be described in the patient’s clinical records together with a presumed diagnosis and possible differential diagnosis.

The patient should receive information on the technique that will be performed and the reasons why it is performed, avoiding terms that may cause anxiety. Informed consent is required.

Regarding the surgical technique:

• Regional block local analgesia rather than infiltrative techniques is preferred;

• elliptical incisions should be attempted in order to ease suture;

• incisions parallel to nerves and vases are preferred;

• if the lesion is smaller than 1 cm, excisional biopsy should be performed. If larger, an incisional technique including representative areas of the lesion with healthy margins should be chosen;

• when a malignant lesion is suspected, incisional technique is mandatory.

Samples must be oriented with a suture or a piece of paper, and introduced in a container with a fixing solution (10% formalin) (Fig.3)

The number and location of the biopsies will be decided on the basis of the clinical appearance of the lesion. If a lesion shows several areas where biopsy would be indicated, more than one sample should be taken. In these cases with precancerous or suspicious lesions, toluidine blue staining could be useful to choose the areas most relevant to biopsy.

The biopsy should be large enough to include normal and suspicious tissue and for the pathologist to give a diagnosis without further specimens (small samples are difficult to orientate and handle and certain processes as sample fixation may end in a reduction of the size of the specimen).

There are different procedures for undertaking oral biopsies. However, the selection of both technique and surgical instruments to use to avoid artefacts is controversial. The use of CO2 laser for the procurement of diagnostic biopsy specimens is compromised by thermal cytological artefacts. Problems of this nature are also witnessed with electrocautery. Punch biopsy has been suggested to reduce artefacts (Fig.4), although this has not been confirmed under controlled experimental conditions. Punch biopsy may tear the tissue in vesiculobullous conditions. Scalpel biopsy is the most widely accepted technique and the one that shows fewer limitations for obtaining samples from the oral cavity.



Scalpel technique for biopsy taking

In order to obtain good visibility, good illumination is needed. A Farabeuf-type separator or similar instrument to retract the lips and cheeks, and moderate-volume surgical aspiration are required.

The instruments suggested are:

- Cartridge-type local anaesthetic syringe

- Fine, single use, two-sided needles

- Cartridges of local anaesthetic solution

- Small and short scalpel blades (no. 15, 11, 12 or even 5)

- Mosquito forceps

- Allis tweezers

- 2/0 to 5/0 non-traumatic suture material

- Gauze

- Container with fixing solution

A biopsy technique can be reduced to six steps: selection of the area to biopsy, preparation of the surgical field, local anaesthesia, incision, handling of the specimen and suture of the resulting wound.

1. Selection of the area to biopsy

When dealing with small-sized lesion, an excisional biopsy will be performed, whereas incisional biopsy performed in the most representative area of the lesion is used for large lesions (long axis larger than 1 cm). If there is any doubt about the malignant character of the lesion, vital staining with toluidine blue can be use as an adjunct to select representative areas (Fig.5). Toluidine blue is a basic dye that fixes to nucleic acids and stains the nuclear content of malignant cells; in these cases samples should be taken from areas with deep blue patches, as light blue areas are not significant. Toluidine blue is used in three steps:

• wash the area with 1% acetic acid

• apply a 1% toluidine blue water solution for 1 minute

• mouthwash with 1% acetic acid

The sample must include healthy tissue at the margin of the lesion.

2. Preparation of the surgical field

The surgical area is disinfected with a quaternary ammonium compound. Iodine-containing surface antiseptics should not be used, as they may stain the tissues. A 0.12- 0.20 % chlorhexidine solution is preferred.

3. Local anaesthesia

An amide-type local anaesthetic with vasoconstrictor should be used and infiltrated away from the lesion are to avoid introducing artefacts in the sample.

4. The incision

Oral tissues should be immobilized far from the area to biopsy with non-toothed tweezers. A clean and defined incision is performed to obtain a slice of tissue when aiming at incisional biopsy. Soft tissues incisions should be elliptical in shape producing a “V” wedge that includes both the lesion and healthy margins. If various lesions are present, multiple biopsies should be taken.

5. Tissue handling

The specimen is handled gently to avoid crush artefacts and introduced in the fixing solution. The role of the fixing agent is to preserve the cellular architecture of the tissues. There are authors that suggest the placement of the specimen on a sterile paper with the mucous surface facing upwards to avoid distortion and curling of the sample margins.

The best fixing agent is a 10% formalin solution, as it induces less ultrastructural alterations in the samples. 70% ethanol can also be used. The samples should never be put in isopropyl or methyl alcohol, saline or distilled water - as severe alterations may be provoked.

The volume of the fixing agent should exceed 10 to 20-fold the volume of the sample.

When immunofluorescence or immunostaining are needed, specimens should not be fixed, but sent as soon as possible to the laboratory for freezing or put in Michel’s solution.

When the material is sent to the pathologist, it should be accompanied with a detailed report that includes identification of the patient, clinical records, clinical signs and a probable diagnosis as well as the orientation of the sample. An explanatory diagram of the biopsy area may be useful for this purpose.

6. Suture

The suture should achieve good haemostasis, facilitate healing and should be removed after 6-8 days.



What are the most frequent errors that should be avoided when taking oral biopsies?

In order to obtain a quality, artefact-free oral biopsy that permits the pathologist establish a histological diagnosis, the clinician should avoid:

• pressing the sample with the tweezers, particularly if toothed, as may produce tissue tears and “pseudomicrocysts”

• infiltrating anaesthetic solution within the lesion, as it can cause sample alterations

• applying products to the lesion that induce tissue modifications

• using an insufficient volume of fixing solution

• inclusion of undesired material in the sample: glove powder, calculus, restorative materials, etc.

• taking insufficient amount of tissue in extension and depth.

BLEACHING TECHNIQUE--- POLAOFFICE

HOME CARE TIPS

'Intelligent' materials to revolutionize surgical implants

A brand new process that could revolutionise the reliability and durability of surgical implants, such as hip and knee replacements, has today , 2 December 08, received recognition for its medical and commercial potential by achieving one of the world's most sought after accolades. A team of researchers, led by the Science and Technology Facilities Council (STFC), has received a Medical Futures Innovation Award for its high technology process designed to coat surgical implants with fibres that, for the first time, will encourage the implant to 'bond' with living bone and to last the lifetime of the patient.

This unique surface engineering process is being developed at the Micro-Nano Technology Centre (MNTC) at STFC. In collaboration with the Electrospinning Company Ltd (TECL) and Anglia Ruskin University, the concept will be taken forward under the guidance of a Medical Futures team, and eventually exclusively licensed to TECL, a spin out company of STFC.

This advanced nanotechnology technique builds on an existing technique known as electrospinning, and will utilise a vastly superior electrospinning source to create bespoke fibrous materials. Electrospinning is a process that uses an electrical charge to turn polymers into extremely thin fibres that are 'spun' to form a mat of fine fibres. It is seen as a platform technology for the medical sector with a wide range of applications including tissue regeneration and drug delivery. The MNTC has developed systems to increase the production rate of nanofibres which has been previously prevented this technology from being adopted by industry.

In this case, nanosized hair- like structures, a thousand times thinner than the width of a human hair, are electrospun at MNTC and added to the surface of an orthopaedic implant to create a 'living interface' between the artificial implants and living bone. Not only does this improve the performance of the implants it also significantly increases their durability to last the lifetime of the patient. Any stress on the implant is relieved, making it more reliable and durable. Additionally, it is also possible to add a unique biological coating that can facilitate growth and improve the bonding of healthy tissue to the implant, primarily benefitting patients with osteoarthritis in the aging population and sports injuries in the younger population.

This process will be transferred to UK industry and TECL will provide access to state-of-the-art electrospinning systems. TECL has spun out from STFC to provide open access to electrospinning equipments and expertise to organisations that would like to explore the technique's potential. The main benefit is that this can be done without commercial companies committing to capital investment or developing in-house expertise until the potential value of electrospinning to the organisation is fully understood. TECL is based both at the Daresbury Science and Innovation Campus in Cheshire and at STFC's Rutherford Appleton Laboratory in Oxfordshire, and was founded by CLIK, the wholly-owned technology exploitation company of STFC. TECL's specialised facilities are designed to extend current electrospinning capabilities so that nanofibres can be reproduced in volume.

Dr Robert Stevens, Head of the MNTC at STFC said: "This award provides a major step forward for the future of patients requiring surgical implants and I am thrilled that this concept was selected as an award winner over several hundred entries. Our award is given for translational research innovation to meet the current and future orthopaedic needs of patients."

Mansel Williams, Chief Executive of The Electrospinning Company said: "Ten percent of patients receiving surgical implants go on to develop infection and loosening of their implants, costing the UK at least £14 million every year, £224 million globally. We want to eliminate this by creating the ideal implant surface matched to the individual patient, benefitting both the patient and the economy. This award will now allow us to scale up the testing and commercialisation of these implants"

Source : Science and Technology Facilities Council

APPARENT SUCCESSFUL CURE OF AIDS

The apparent success of a case in which German doctors cured a man of AIDS using a bone marrow transplant comes as no surprise to Gerhard Bauer, a UC Davis stem cell researcher. Bauer has been working for more than 10 years on a similar cure for AIDS based on replacing the devastated immune system of an HIV-infected patient with stem cells that have been engineered to resist human immunodeficiency syndrome.

Bauer plans to present the preliminary results of his latest research at the 50th annual meeting of the American Society for Hematology in San Francisco on Sunday, December 6, 2008, from 6 to 8 p.m. at the Moscone Center. He and his UC Davis research team will present a poster detailing the development of a mouse model that allows pre-clinical testing of their new gene-therapy protocol, which they hope will pave the way for human clinical trials within five years.

"The case in Germany was a natural gene-therapy experiment," explained Bauer, an assistant professor of hematology and oncology and director of a good manufacturing practice (GMP) laboratory now under construction in the new UC Davis Institute for Regenerative Cures in Sacramento. "We are working on a similar approach to genetically engineer a patient's own stem cells in a way that mimics this natural immunity. The German case offers further proof that genetic engineering provides a pathway to success, and gene therapy offers real hope as a cure for AIDS."

Last month, German doctors reported that they had cured a 42-year-old of acquired immune deficiency syndrome, or AIDS. The patient, an American living in Berlin, also had leukemia, which is best treated by a bone marrow transplant. Thinking they might be able to cure the man of both diseases, the physicians gave him a bone marrow transplant from a person with natural immunity to HIV. The patient has now lived for 20 months since the transplant without any detectable traces of HIV.

To establish similar immunity in HIV patients, the UC Davis team manipulated human skin cells to give these cells many of the same properties as stem cells. These transformed cells, called induced pluripotent stem (IPS) cells, are capable of differentiating into, among other cell types, hematopoietic stem cells, which are normally found in bone marrow and are responsible for producing the various types of immune cells.

"If we can replace normal immune cells with HIV-resistant ones, we can cure AIDS," Bauer said.

Bauer and stem cell program research associate Joseph Anderson have developed several anti-HIV genes that they plan to insert into IPS cells using standard gene-therapy techniques and viral vectors (viruses that efficiently insert the genes they carry into host cells). These engineered IPS cells could then be differentiated into bone marrow stem cells and introduced into the patient using a procedure similar to a bone marrow transplant.

"The hope is that one day we will use a patient's own skin cells to develop the engineered IPS cells to avoid possible rejection," said Bauer, who worked on clinical HIV gene therapy trials at Childrens Hospital Los Angeles before coming to UC Davis. "As in the German case, the end result would be an immune system that produces HIV-resistant immune cells."

In theory, the experimental treatment would result in an immune system that remains functional, even in the face of an HIV infection, but would halt or slow the progression toward AIDS.

"The anti-HIV genes take advantage of how HIV works," added Anderson, who is now writing a paper about the investigation. "The virus targets cells that are descendants of hemopoeitic stem cells."

During the first stages of infection, HIV targets macrophage cells, gaining entrance into the cell by binding to a receptor called CCR5 on the cell's surface. Later in the infection it targets CD4+ T cells, binding to the CXCR4 receptor on the surface of these cells and bringing on full-blown AIDS.

What researchers discovered is that there is a natural mutation in less than 1 percent of Caucasians that results in a lack of CCR5 receptors on any of their cells.

"We also found that these people are naturally resistant to HIV," said Bauer. "So, more than 10 years ago, we began our work creating a gene that would knock down expression of CCR5 and other key receptors and interfere with other routes of HIV infection."

For IPS-based anti-HIV gene therapy to become reality, UC Davis researchers must first conduct safety and efficacy trials. Researchers have created a mouse model that replicates a normally functioning human immune system.

"We can now move forward and test the safety of the viral vectors, as well as the ability of anti-HIV genes to inhibit HIV infection," noted Anderson. "The humanized mouse model is an important step toward bringing this possible cure to patients."

Bauer and Anderson are hoping to demonstrate in their mouse model that HIV-infection cannot occur following their gene therapy treatment, providing the needed confidence in safety before embarking on clinical trials. This work and studies on the clinical use of IPS cells, Bauer predicts, will lead to a cure for AIDS.

"A real cure will come when we can replace all the hematopoietic stem cells with HIV resistant stem cells. What is so exciting is that we're clearly on the path of doing just that," said Bauer.

Source : University of California - Davis - Health System

Scientists develop new tool to improve oral hygiene

Scientists at the University of Liverpool have developed a new dental product to identify plaque build-up in the mouth before it is visible to the human eye.

The toothbrush-sized product has a blue light at its tip, which, when shone around the mouth and viewed through yellow glasses with a red filter, allows plaque to be seen easily as a red glow. The device, produced in collaboration with dental and healthcare developers, Inspektor Research Systems BV, has been designed for everyday use in the home.

Dentists currently use disclosing agents in tablet form to uncover tooth decay and plaque but these often stain the mouth and taste unpleasant. The new product, known as Inspektor TC, will be particularly useful for those who are vulnerable to dental diseases such as children and the elderly.

Children in the UK have had an average of 2.5 teeth filled or removed by the age of 15 because of tooth decay. In young people alone £45 million is currently being spent every year on the problem.

Professor Sue Higham, from the University's School of Dental Sciences, said: "It is extremely difficult to get rid of all plaque in the mouth. Left undisturbed it becomes what we call 'mature' plaque and gets thicker. This is what leads to gingivitis, or bleeding gums, and decay.

"Early stage plaque is invisible, and so this device will show people the parts of the mouth that they are neglecting when they brush their teeth, enabling them to remove plaque before it becomes a problem.