Biomedical subjects

R Vaamonde-Lemos

Publications and source records attributed to R Vaamonde-Lemos.

8 recordsLinked to original sources

PubMed1994

Multivariate discriminant analysis of normal, intraepithelial neoplasia and human papillomavirus infection of the uterine cervix samples.

The present investigation studies the role of multivariate statistical methods on quantitative histopathological features of cells in uterine cervix epithelium to discriminate between normal and abnormal uterine cervix samples. 143 histological specimens were included in the study involving normal cervix, cervical intraepithelial neoplasia (CIN) lesions and cervical human papillomavirus (HPV) infection with and without CIN (condyloma-CIN and condyloma-NCIN groups, respectively). Deep, middle and superficial regions of the cervical squamous epithelium were morphometrically analyzed. Identification of normal cervix from pathological cases was highly achieved with a specificity of 100%. The application of discriminant statistical method within pathological specimens showed an acceptable percentage of cases correctly classified; thus, an efficiency of 83.0% and 74.6% was obtained in order to discriminate within CIN and condyloma-CIN grades respectively. These percentages increased when differentiation between each grade of CIN versus condyloma-CIN were considered, using only 1-3 morphometrical parameters. Our findings indicate that the combination of nuclear and cytoplasmic quantitative features, specially size parameters, permit a high correct percentage classification of cervix samples. The discrimination process was better when few diagnostic categories were included; however, 100% specificity for normal samples was always reached.

Cell Nucleus↗

PubMed1993

Histomorphometry of normal and abnormal endometrial samples.

One hundred forty samples of normal and pathological endometrium were examined morphometrically in order to achieve a discriminant function among normal and pathological diagnoses. Samples of proliferative and secretory normal endometrium, simple and atypical hyperplasia, and well-differentiated adenocarcinoma were included in this study. Morphometrical and stereological characteristics for both glands and lumina as well as epithelium were registered. Stepwise discriminant analysis was performed. There is an increase in size of glands from proliferative endometrium to well-differentiated adenocarcinoma. The stereological measurements parallel morphometrical measurements. The accuracy of diagnosis by morphometrical and stereological means were 91% when the normal group (proliferative and secretory phase) were included. Accuracy increases to 95% when only three pathological groups were used; only one simple hyperplasia and one well-differentiated adenocarcinoma were incorrectly diagnosed. In all functions, the volume density of epithelium was selected. The reproducibility on a new data set demonstrates an efficiency of 92, 87, and 100% for three discriminant analyses (five, four, and three diagnostic groups, respectively).

Adenocarcinoma↗

PubMed1993

Histomorphometry of normal and abnormal cervical samples.

We quantitatively studied the nuclear and cytoplasmic characteristics of cells in the normal cervix, squamous intraepithelial lesions (cervical intraepithelial neoplasia [CIN]) lesions and cervical human papillomavirus (HPV) infection with and without CIN (condyloma-CIN and condyloma-NCIN groups, respectively). The morphometric features of the deep, middle and superficial layers of the cervical epithelium were calculated on 143 cervical samples. The morphometric parameters selected for the analysis were area; perimeter; maximal, minimal and equivalent circle diameters; nuclear/cytoplasmic ratio; and several shape factors. Our quantitative findings support the opinion of other authors that HPV infection is associated with shape and size modifications of the nucleus and cytoplasm in CIN. In relation to cellular size, there were no differences between a normal cell, regardless of its region, and a virus-infected cell. The nuclear differences are predominantly in the deep layer areas. The CIN samples showed changes in both cellular and nuclear form and size but lacked substantial differences in the tumor grades and areas studied. The condyloma-CIN samples revealed more notable differences in both tumor grade differentiation and different cellular layers.

Cell Nucleus↗

PubMed1993

Stereological estimates of volume-weighted mean glomerular volume in streptozotocin-diabetic rats.

BACKGROUND: The stereological estimate of mean glomerular volume is an objective and reproducible method of measuring glomerular size in terms of absolute volume. This method provides objective, unbiased, and reproducible data that may be used in the description of glomeruli. EXPERIMENTAL DESIGN: We have made a morphometric analysis of glomerular size in three cortical areas (superficial, midcortical, and juxtamedullary) in normal and diabetic animals, using the point-sampled intercepts method. The kidney weight and volume as well as the cortical and glomerular volume density were also calculated. Our study included 35 animals (5 control and 30 experimental). Fifteen experimental animals were treated with 50 mg/kg streptozotocin dissolved in citrate buffer at pH 4.5. The other 15 animals were sham injected with citrate buffer. In all cases the tissues were fixed in 10% formaldehyde and embedded in paraffin. Sections were cut at 4 microns and stained with periodic acid-Schiff and a systematic sampling was performed. RESULTS: In the control and experimental groups the juxtamedullary glomeruli was significantly larger than superficial and midcortical glomeruli. Mean values of the kidney weight and volume and the volume-weighted mean glomerular volume show a significant increase at 4, 20, and 50 days after streptozotocin-induced diabetes. CONCLUSIONS: The increase in the volume-weighted mean glomerular volume was similar in the three cortical areas, thus suggesting that the effect of diabetes on glomerular enlargement is similar in all cortical areas.

Animals↗

PubMed1992

Stereological estimates of nuclear volume in carcinoma of the ampulla of Vater.

The stereological estimate of mean nuclear volume is an objective and reproducible method of measurement of nuclear size in terms of absolute volume. We have used this method to study carcinomas of the ampulla of Vater. Our study includes 21 cases--five papillary and 16 intestinal--all treated by the same surgical procedure. The volume-weighted mean nuclear volume (nuclear nu v) and the mean nuclear area were calculated. The mean volumes of nuclear nu v were significantly different (P less than 0.01) between the papillary and intestinal carcinomas, but no differences were found between normal mucosa and papillary carcinoma. The variance was significantly larger in the intestinal group than the papillary and normal groups. The nuclear nu v showed a significant association with survival, larger nuclear nu v (greater than 150 microns 3) being associated with a lower survival rate.

Ampulla of Vater↗

PubMed1992

Morphometry and discriminant analysis of the endometrium.

The authors dated 100 normal endometrial biopsies. Only endometrial specimens with histologically confirmed subphases and no evidence of organic disease were accepted for study. The morphometry and stereologic measures of the glands, lumina and endometrial epithelium were assessed. Quantitative assessment of the normal endometrium supported the histologic events that occur in the endometrial cycle (proliferative and secretory phases). There was a progressive increase in morphometric and stereologic values of the glands, epithelium and lumina during the endometrial cycle. Using stepwise discriminant analysis, 94% of the specimens were correctly classified into the categories of proliferative and secretory phase; two quantitative parameters were required, the epithelial volume density and longest luminal diameter. When three subphases within proliferative and secretory endometrium were considered, the overall accuracy was 90% and 78%, respectively.

Biopsy↗

PubMed1991

Capillary and fiber size interrelationships in regenerating rat soleus muscle after ischemia: a quantitative study.

The present study examines the influence of ischemia on the muscle fibers and capillarization in rats. Muscle ischemia was achieved by a pneumatic tourniquet at a pressure of 300 mm Hg for 2, 4 and 6 h (groups I, II and III, respectively) to the right hindlimb above the knee. Numerous regenerative fibers were seen at 4 and, especially, 8 and 12 days after ischemia in groups II and III. The quantitative data revealed a significant decrease in the size of muscle fibers (regenerative fibers) in ischemic skeletal muscle, with a concomitant increase in fiber density. The capillary to fiber ratio shows a decrease at 4, 8 and 12 days after ischemia in the three experimental groups: in group I because of a decrease in capillary density; in groups II and III because of an increase in fiber density with respect to capillary density.

Animals↗

PubMed1990

Quantitative study of the microvascular pattern in tourniquet-induced muscle ischemia.

Experiments were carried out on 40 adult Wistar rats to determine the effect of the application of a pneumatic tourniquet on the capillary network of the tibialis anterior muscles. The tourniquet was applied for four hours to the right hind limb above the knee. During the degeneration processes (6 to 24 hours postischemia), the capillary density and capillary-to-fiber ratio decreased significantly with respect to a control group of untreated animals. In the subsequent regenerative processes, there was a greater increase of fiber density than of capillary density, resulting in a capillary-to-fiber ratio lower than that of the control group. In the last period (30 to 90 days postischemia), both capillary density and fiber density returned to normal values.

Animals↗