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Biomedical subjects

R Gelman

Publications and source records attributed to R Gelman.

10 recordsLinked to original sources
PubMed1992

Lymphocyte subsets in healthy children during the first 5 years of life.

OBJECTIVE: To assess whether relative and absolute values of CD4 and CD8 lymphocytes and CD4/CD8 ratio change in relation to age, and to estimate the fifth and 95th percentiles for these values in children of various ages. PATIENTS AND METHODS: Phenotypic analysis of lymphocyte subsets was performed on blood samples from 208 healthy children, aged 1 through 59 months, using standard flow cytometric techniques. RESULTS: Regression analysis demonstrated that CD4 and CD8 lymphocyte counts declined significantly with advancing age (P less than .000001 and P = .03, respectively). Since CD4 and CD8 counts depend on total lymphocyte count, the percentage of total lymphocytes of each phenotype was also analyzed and demonstrated that the CD4 percentage was highly age dependent (P less than .000001). The CD8 percentage increased with age (P = .0001) but not as much as the CD4 percentage decreased. Median CD4 counts (fifth and 95th percentiles) for children 2 through 3, 4 through 8, 12 through 23, and 24 through 59 months of age were 2.83 (1.46 to 5.11), 2.95 (1.69 to 4.61), 2.07 (1.02 to 3.60), and 1.80 (0.90 to 2.86) x 10(9)/L, respectively. CONCLUSION: Healthy children's CD4 lymphocyte counts are considerably higher than previously established adult values. These data demonstrate that age is an important consideration in interpretation of lymphocyte subsets in children. This may be especially relevant in children who are infected with the human immunodeficiency virus, where CD4 lymphocyte values play a central role in monitoring disease progression and determining thresholds for medical interventions.

CD4-CD8 Ratio↗
PubMed1992

Preverbal and verbal counting and computation.

We describe the preverbal system of counting and arithmetic reasoning revealed by experiments on numerical representations in animals. In this system, numerosities are represented by magnitudes, which are rapidly but inaccurately generated by the Meck and Church (1983) preverbal counting mechanism. We suggest the following. (1) The preverbal counting mechanism is the source of the implicit principles that guide the acquisition of verbal counting. (2) The preverbal system of arithmetic computation provides the framework for the assimilation of the verbal system. (3) Learning to count involves, in part, learning a mapping from the preverbal numerical magnitudes to the verbal and written number symbols and the inverse mappings from these symbols to the preverbal magnitudes. (4) Subitizing is the use of the preverbal counting process and the mapping from the resulting magnitudes to number words in order to generate rapidly the number words for small numerosities. (5) The retrieval of the number facts, which plays a central role in verbal computation, is mediated via the inverse mappings from verbal and written numbers to the preverbal magnitudes and the use of these magnitudes to find the appropriate cells in tabular arrangements of the answers. (6) This model of the fact retrieval process accounts for the salient features of the reaction time differences and error patterns revealed by experiments on mental arithmetic. (7) The application of verbal and written computational algorithms goes on in parallel with, and is to some extent guided by, preverbal computations, both in the child and in the adult.

Animals↗
PubMed1992

Interobserver reproducibility in the diagnosis of ductal proliferative breast lesions using standardized criteria.

Although the categorization of proliferative breast lesions provides valuable information regarding subsequent risk of breast cancer, the ability of pathologists to classify such lesions in a reproducible fashion has not been adequately evaluated. To assess further interobserver reproducibility in the categorization of proliferative breast lesions, six pathologists each reviewed 24 proliferative ductal lesions and classified them as either usual hyperplasia (H), atypical hyperplasia (AH), or carcinoma in situ (CIS). Before evaluation of the study slides, all the participants were instructed to use the diagnostic criteria of Page and co-workers and were provided with both a written summary of these criteria and a set of teaching slides with representative examples of each type of lesion. Complete agreement among all six pathologists was seen in 14 cases (58%); five or more agreed in 17 cases (71%); and four or more arrived at the same diagnosis in 22 cases (92%). No pathologist consistently rendered more "benign" or "malignant" diagnoses than any other. After assigning numerical values for each diagnostic category (H = 1, AH = 2, CIS = 3), the scores for the group of 24 cases did not differ significantly by pathologist (p = 0.68; average score range, 1.7-2.0). Our results indicate that with the use of standardized criteria, interobserver concordance in the diagnosis of proliferative ductal breast lesions can be obtained in the majority of cases.

Breast↗
PubMed1992

Normal uptake in a gravid uterus on Tc-99m DTPA imaging.

A 17-year-old female kidney transplant patient was admitted to the hospital with a fever and right lower quadrant pain. Although she was 14 weeks' pregnant, renal DTPA imaging was performed because graft rejection was suspected. The study revealed fetal uptake of DTPA medial to the transplanted kidney. This has not been previously reported. Uptake in a normal uterus has been described using Tc-99m pertechnetate, Tc-99m glucoheptonate, and Tc-99m MDP. It is essential to recognize uptake in the gravid uterus and to differentiate it from uptake secondary to a pathologic entity.

Adolescent↗
PubMed1992

Recurrence in the breast following conservative surgery and radiation therapy for early-stage breast cancer.

This report summarizes the experience of the Joint Center for Radiation Therapy (JCRT) in treating patients with clinical stage I and II breast cancer with conservative surgery and radiation therapy. The study population consisted of 1396 patients treated between 1968 and 1985. All patients underwent a gross excision of the tumor and received breast irradiation (with or without nodal irradiation) including a "boost" to bring the primary tumor site to a total dose of at least 60 Gy. The method of treatment evolved over the study-time period. During the interval from 1968 to 1982, patients typically underwent a limited gross excision of the tumor without regard to the microscopic margins of resection. During the period 1983 to 1985, film-screen mammography, inking of specimen margins, and reexcisions for inevaluable or involved margins were more commonly performed. With a median follow-up of 80 months, the 5-year crude rate of failure in the breast (as the first site of failure) was 8% (106/1396) and the crude rate of regional nodal/distant failure (as the first site of failure) was 16% (228/1396). The time-course of failures in the breast was protracted, occurring at a fairly constant rate over the first 7 years after treatment, but still seen beyond that point. Most recurrences in the breast (75%) developed at or near the original tumor site. The most important risk factor for developing a breast recurrence was the presence of an extensive intraductal component in the tumor. The cosmetic results following treatment were excellent or good in the majority of patients (87%) and were most adversely affected by extensive surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1991

The use of radionuclide imaging in the evaluation of suspected biliary damage during laparoscopic cholecystectomy.

Laparoscopic cholecystectomy offers a reliable and effective alternative to the standard operative cholecystectomy with reduced morbidity and patient recovery time. We report three cases in which radionuclide hepatobiliary imaging was utilized to evaluate the integrity of the extrahepatic biliary ducts following suspected biliary damage during the procedure, documenting bile leakage in two of the patients.

Adult↗