Israel Medical Association Journal

Background: HER2 is an important prognostic and predictive marker in invasive breast cancer. It is currently assessed by immunohistochemistry for protein over-expression and by fluorescence in situ hybridization for gene amplification. The immunohistochemistry-equivocal cases (2+) are currently retested by FISH[1] to determine eligibility for trastuzumab treatment. Retesting by FISH significantly raises the cost of patient management and sometimes delays treatment. The 4B5 is a new, FDA-approved, rabbit monoclonal antibody for HER2 testing.

Objectives: To examine the reliability of 4B5 IHC[2] HER2 testing in cases found to be HER2 status equivocal by CB11 IHC.

Methods: Twenty-eight invasive breast cancer cases, with an equivocal HER2 status by CB11 IHC, were retested by the 4B5 antibody as well as by FISH analysis. The scoring was performed using the same guidelines as HercepTest and was correlated with the FISH ratio. Results: Of the original 28 CB11 clone designated equivocal cases, 14 (50%) showed negative HER2 staining using the 4B5 clone (HercepTest score 0 and 1+). Five cases (18%) proved to be positive (HercepTest score 3+) and 9 cases (32%) remained equivocal (HercepTest score 2+). The corresponding FISH ratio results showed that all 4B5 negative cases were negative by FISH testing, with a negative predictive value of 100% 4 of 5 of the 4B5-positive cases were positive by FISH testing, with a positive predictive value of 80%. One 4B5-positive case was borderline-high (2.2 ratio) by FISH. The correlation between 4B5 IHC and FISH was statistically significant (P = 0.0013) by chi-square test.

Conclusions: Sequential testing by 4B5 IHC could greatly reduce the need for FISH testing in cases considered HER2 equivocal by CB11 IHC.
 

 
[1] FISH = fluorescence in situ hybridization

[2] IHC = immunohistochemistry

Background: Heterotopic ossification is a common complication of hip surgery and musculoskeletal or brain traumas.

Objectives: To confirm by in vivo study that colchicine inhibits osteoblast cell proliferation with marked decrease in tissue mineralization.

Methods: Heterotopic ossification was induced in three groups of New Zealand white rabbits (females, 6 months old, weight 3–3.5 kg) by injecting 2 ml bone marrow drawn from the iliac crest into their right thigh muscle. To prevent heterotopic ossification, colchicine (0.25 mg/day) was administered orally for 4 weeks to two groups of adult rabbits: group A (preload group) – 1 week preceding bone marrow injection; group B – on day of injection; and group C – control group.

Results: After 4 weeks the rabbits were evaluated by radiographs and ultrasound for evidence of heterotopic ossification. At the end of the study histologic samples were taken from all the thighs. Imaging and histologic studies showed, with statistical significance, almost complete prevention of heterotopic ossification formation in group A (preload) and a marked decrease in group B, when compared with the controls in whom large new bone had formed at the injection site. These results indicated the inhibitory effects of colchicine on a bone-forming process in soft tissue such as heterotopic ossification.

Conclusions: The role of colchicine in preventing heterotopic ossification in other bone-forming conditions, such as hip arthroplasty or pelvic trauma, and after brain trauma, remains to be evaluated in a clinical setting.

Background: Ciguatera poisoning is the commonest fish-borne seafood intoxication. It is endemic to warm water tropical areas and is caused by consumption of bottom-dwelling shore reef fish, mostly during spring and summer. The causative agent, ciguatoxin, is a heat-stable ester complex that becomes concentrated in fish feeding on toxic dinoflagellates. The common clinical manifestations are a combination of gastrointestinal and neurologic symptoms. Severe poisoning may be associated with seizures and respiratory paralysis.

Objective: To describe a series of patients who sustained ciguatera poisoning from an uncommon region and an unexpected source.

Patients: Two families complained of a sensation of “electrical currents,” tremors, muscle cramps, nightmares, hallucinations, agitation, anxiety and nausea of varying severity several hours after consuming rabbitfish (“aras”). These symptoms lasted between 12 and 30 hours and resolved completely. The temporal relationship to a summer fish meal, the typical clinical manifestations along with the known feeding pattern of the rabbitfish suggested ciguatera poisoning.

Conclusions: The Eastern Mediterranean basin is an unusual region and the rabbitfish an unusual source for ciguatera poisoning. There are no readily available and reliable means for detecting ciguatoxin in humans. A high index of suspicion is needed for diagnosis and a thorough differential diagnosis is essential to eliminate other poisonings, decompression sickness and encephalitis. Supportive therapy is the mainstay of treatment.

Background: Most corneal damage induced by contact lenses is due to interference with corneal oxygenation.

Objective: To investigate the effect on the rabbit cornea of a rigid gas-permeable contact lens with a newly designed periphery.

Method: We fitted New Zealand white rabbits (n=12) with RGP[1] contact lenses that were identical in all respects except for the design of the periphery. In each animal, one contact lens had an innovative periphery consisting of a microscopic diffractive relief lathed on the back surface; the other contact lens was of a conventional design. The lenses were worn continuously for 7 days. During this experimental period and for 1 additional week we assessed the corneal damage by daily testing lactic dehydrogenase activity in the tears.

Results: On the last day of the experimental week and the first 3 days of the healing period, mean tear LDH[2] activity was significantly lower in the eyes with the new contact lens design than in eyes with the conventional lenses.

Conclusions: The novel periphery design reduces corneal damage resulting from contact lens wear, as reflected by LDH levels in the tears. The new design probably facilitates the flow and exchange of tears under the contact lens, resulting in improved metabolism of the cornea. These findings may also prove applicable to soft contact lenses.