Combined and Sequential Expression of p53, Rb, Ras and Bcl-2 in Bronchial Preneoplastic Lesions

Aims and background

Several simple molecular abnormalities have been detected in bronchial preneoplastic lesions, but the simultaneous presence of these alterations has been scarcely investigated.

Methods

We studied, by an immunohistochemical method, the expression of p53, Rb, Ras and Bcl-2 in 65 samples from surgical specimens and diagnostic biopsies selected for the presence of preneoplastic changes in the bronchial epithelium. To perform an analysis of the combined expression of all markers in the same areas, we accurately mapped every consecutive section on which immunohistochemical reactions were performed, subdividing each specimen into 25x microscopic fields, which allowed good topographical mapping.

Results

It was found that the frequency of p53-positive and Rb-negative microscopic fields was directly related to the morphological grading of lesions. On the other hand, Ras expression characterized high-grade lesions not showing squamous differentiation (non-squamous Cis). Regarding Bcl-2 expression, only slight differences in positivity distribution were found between the different lesions. More interesting was the parallel evaluation of all markers in the same areas: one of the main patterns, found to be correlated with the severity of histopathological features, was characterized by combined p53 hyperexpression/Rb hypoexpression; furthermore, when Ras and Bcl-2 hyperexpression were superimposed to the above pattern, the former mainly characterized non-squamous Cis, while the latter was present only in high-grade squamous lesions. However, the most frequently encountered pattern did not show any alteration of the studied markers, suggesting that other mechanisms could be involved in bronchial carcinogenesis.

Conclusions

The detection of combined molecular abnormalities in bronchial preneoplasia could clarify the steps involved in lung carcinogenesis; furthermore, a simple and inexpensive method, such as immunohistochemistry, could be routinely applied also to cytologic specimens in order to detect those lesions, or patients, that are prone to progression towards lung cancer.

Transmission ratio distortion in the spinal muscular atrophy locus: Data from 314 prenatal tests

BACKGROUND

Spinal muscular atrophy (SMA) is a recessive neurodegenerative disorder characterized by the loss of alpha-motor neurons in the spinal cord and subsequent death of motor neuron cells. SMA occurs with a frequency of 1 in 6,000 live births, with a carrier frequency of 1 in 40, and is a leading genetic cause of infant mortality. SMA is caused by loss or mutation of the telomeric survival motor neuron gene (SMN1), which is deleted in almost 94% of SMA patients

OBJECTIVE

To analyze the transmission ratio at the SMA locus, examining the segregation of the SMN1-deleted alleles in 314 fetuses from carrier parents who requested prenatal testing for the disease.

METHODS

Prenatal diagnosis of SMA in families at 25% risk of the disease has been performed on chorionic villous sampling specimens, through direct detection of the SMN1 gene mutation and linkage analysis using microsatellite markers from the 5q13 region. Analysis of the genotypic/allelic frequencies of the SMN1 gene was performed using the chi2 test, assuming a recessive mendelian inheritance.

RESULTS

Of 314 fetuses analyzed, 95 were homozygous for the wild-type allele (30.3%), 154 were carriers (49.0%), and the remaining 65 were homozygous for the mutated allele (20.7%). Statistical analysis demonstrated that proportion of fetuses predicted with SMA is lower than 25% expected for a recessive disorder, resulting in a transmission rate of the SMN1-deleted allele deviant from the 50% expected in a random the segregation of a mendelian tract (p = 0.016)

CONCLUSIONS

This is the first study to evaluate the genotypic frequencies at the spinal muscular atrophy (SMA) locus based on data derived from prenatal analysis, which are not subject to ascertainment bias. The analysis showed a transmission ratio distortion at the SMA locus in favor of the SMN1 wild-type alleles.

Bone mass evaluated by calcaneous ultrasound and radial peripheral computed tomography in 726 youngsters

AIM

To compare the results of ultrasound and computed peripheral tomography in evaluating bone mass in a population of normal children.

METHODS

Seven hundred and twenty-six healthy school children (260 males; age 8.3-20.9 y) underwent calcaneous ultrasound and peripheral computed tomography at the ultradistal radius. Broadband ultrasound attenuation (BUA) and areal and volumetric bone mineral density (aBMD and vBMD) were evaluated. The results were compared and correlated among them and with auxological parameters (height, BMI and pubertal stages) using the software package SPSS for Windows.

RESULTS

The three variables examined (BUA, aBMD and vBMD) all showed a progressive increase with age and a positive correlation with age, height and BMI. When the population was subdivided according to pubertal stages, all variables showed a progressive increase, the difference being significant when stages 1-2 were compared with stages 4-5. A significant correlation was present among BUA, aBMD and vBMD even if the Pearson correlation coefficient was not high.

CONCLUSIONS

The similar pattern of BUA, aBMD and vBMD with respect to age, height and pubertal stages indicates that ultrasound could be a reliable method to screen bone mass abnormalities in children. The low correlation coefficient, however, suggests that the methods employed measure different bone parameters. Moreover, the different skeletal locations could also account for these results.

Scintimammography with 99mTc-MIBI and magnetic resonance imaging in the evaluation of breast cancer

This study was performed to evaluate the sensitivity and specificity of technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) scintimammography (SMM) and contrast-enhanced magnetic resonance imaging (MRI) in patients with breast masses, using the histological findings as the gold standard. Forty-five consecutive patients with a breast lesion, detected by self-examination, physical examination or screening mammography, underwent SMM and MRI. In 38 cases (84.5%), the histopathology was malignant; the breast cancers ranged from 3 to 100 mm in diameter (mean 22 mm). In the overall patient group, MRI showed a slightly higher sensitivity than SMM (92% vs 84%), but SMM showed a better specificity: 71% vs 42%. The accuracy was 82% and 84% for SMM and MRI respectively. To evaluate the influence of lesion size on the results, patients with lesions < or =20 mm and < or =15 mm were examined. In patients with lesions < or =20 mm, the sensitivity of SMM and MRI decreased to 64% and 82% respectively, while SMM again displayed considerably better specificity: 83% vs 50% for MRI. The accuracy of SMM and MRI was 64% and 82% respectively. In patients with lesions < or =15 mm, SMM again showed better specificity (75% vs 50%), while MRI displayed better sensitivity and accuracy (sensitivity, 81% vs 62%; accuracy, 75% vs 65%). In this study the specificity of SMM in patients with breast lesions was thus superior to that of MRI. The combination of SMM and MRI may be used in those patients with equivocal findings at mammography and ultrasound to reduce the number of unnecessary surgical biopsies.

How gender and age affect iodine-131-OIH and technetium-99m-MAG3 clearance

OBJECTIVE

The relationship between age and effective renal plasma flow (ERPF) results, as measured in nuclear medicine, is well known. This paper explores the relationships among gender, age, and ERPF measurements. After reading this paper, the nuclear medicine technologist should be able to: (a) discuss the importance of establishing normal range values for ERPF that include age and gender variables; (b) state how age affects ERPF results; and (c) state how gender affects ERPF results.

pQCT (quantitative peripheral tomography) and data evaluation of phosphocalcic metabolism in thalassaemic patients

pQCT is a method which allows the separate determination of cortical and trabecular bone mineral density in the peripheral skeleton. 21 thalassaemic patients (8 females, 13 males) aged from 10 to 32 years, were examined using pQCT at the ultra distal radius to evaluate SSI (Stress-Strain Index). ALP, serum calcium, hydroxyproline, magnesium, IGF-I, and body surface were determined. The results show a good correlation between cortical BMD and age, concentration of hydroxyproline in urine, serum bone Gla protein, body surface index, bone density of trabecular bone and SSI. Good correlation was found between trabecular bone density and age, IGF-I, BGP and PTH, and between SSI and cortical BMD, age and BSI. The linear relationships between age and cortical and trabecular density show an increase of cortical BMD with age and a decrease of trabecular density with age. The same results were obtained considering trabecular and cortical density versus SSI.

SPET imaging of intracranial tumours with 99Tcm-sestamibi

Single photon emission tomography (SPET) employing 99Tcm-sestamibi (MIBI) injected intravenously was performed in 27 patients for pre-surgical evaluation of intraparenchymal brain tumours. A computerized tomography (CT) scan was performed in 26 patients, magnetic resonance imaging (MRI) in 8 patients and digital subtraction angiography (DSA) in 14 patients. Visual analysis of the SPET scans was performed using a 4-point scale relating to background activity, to evaluate MIBI uptake in the tumour. The vascular supply and the cellular component were also evaluated using DSA and CT scans. In normal controls, MIBI uptake was observed in the scalp, in the choroid plexus and in the pituitary gland, but never in normal parenchyma. Among the astrocytoma group of patients, a trend between MIBI uptake and grade of tumour was noted. MIBI uptake in meningiomas depends primarily on the vascular supply. Our results support the hypothesis that vascular supply, integrity of the blood-brain barrier, the degree of malignancy of the neoplasm and the viability of the tumour cells may be related to MIBI uptake.

Continuing loss of vertebral mineral density in renal transplant recipients

This cross-sectional study examined bone abnormalities by digital radiography, bone densitometry and biochemical tests in 44 clinically asymptomatic renal transplant recipients 6-195 months after renal transplantation. Abnormal radiographs were obtained in 40 of the 44 patients. Dual-energy X-ray absorptiometry (DXA) performed at the lumbar spine (L2-L4)/showed a negative Z score in all patients, ranging from -1 to -1.9 in 28 patients and less than -2.0 in 16 patients. The severity of osteopenia increased with the length of time after transplantation and there was a significant correlation with parathyroid hormone values in patients with normal and low glomerular filtration rates. Our data suggest that decreased bone density values (Z score less than -2) are present in about one-third of patients with renal transplants. Bone loss appears to continue after transplantation. Steroid therapy and immunotherapy are probably the cause of this bone loss. Bone mineral measurements alone are helpful in identifying asymptomatic patients with low bone mass after transplantation.

[Diagnostic imaging in renal vascular diseases: old and new ways. Role of nuclear medicine]

Using the nuclear medicine procedures it is possible to evaluate the renovascular hypertension via the captopril test. Decreased renal blood flow due to stenotic vessel may produce a variety of findings on the renogram using both OIH-I131 and DTPA-Tc99m. Delayed transit time and excretion also may be detected. In this situation the sensitivity and specificity of Nuclear Medicine for RAS detection is very low. Using Captopril test is possible to detect enhanced modification on the shape of renogram due to Angiotensin Converting enzyme inhibition.

[Normal ranges of bone mineral content of the distal radius determined with single photon absorptiometry. Study of 1521 cases]

The normal ranges and mathematical equations of bone mineral content (BMC), normalized to radial width (BMC/W) vs. age at the distal radius, were obtained by single photon absorptiometry (SPA), and compared in two different normal populations, one of postmenopausal females and the other of control males. The female population included 1359 postmenopausal women, aged 35 to 75 years; normal control males were 162, of the same age. The results obtained in the two groups of patients show a statistically significant (p less than 0.001) correlation between age and BMC/W, expressed in a polinomial third-degree regression. The slope of the regression curves is quite different between males and females: the mean decrement, evaluated from regression polinomial fits, results 0.5% per year for normal females, and 0.3% per year for normal males. The maximum decrement (1% per year) is observed at the mean age of 51 years, which is the average age of peri-menopausal women in our province (Ferrara). The authors believe SPA to be a simple and reliable technique in measuring peripheral bone loss rate. SPA may be useful in the diagnosis and treatment of postmenopausal women, but is not recommended in the short-term follow-up of osteoporosis.