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Biomedical subjects

G Nathan

Publications and source records attributed to G Nathan.

At least 19 recordsLinked to original sources
PubMed2001

Sentinel lymph node biopsy after neoadjuvant chemotherapy for breast cancer.

BACKGROUND: Sentinel lymph node biopsy (SLNB) is a developing alternative to axillary dissection and may prove to be accurate in the detection of micrometastases in lymph nodes of breast cancer patients. Limited studies exist in the use of SLNB after neoadjuvant therapy. This study was undertaken to determine the accuracy of SLNB after neoadjuvant chemotherapy. METHODS: Thirty-one patients with stage I or II breast cancer underwent SLNB after neoadjuvant chemotherapy. RESULTS: Lymphatic mapping was performed by radioisotope, blue dye, or both techniques. Sentinel nodes (SN) were identified in 29 patients (93.5%). The SN was positive in 11 patients (38.0%), and was the only positive node in 5 patients (45.5%). There were no false negative SN by hematoxyin and eosin stain or immunohistochemistry (IHC) studies. CONCLUSIONS: Sentinel node identification rate is similar to that in nonneoadjuvant studies. The sentinel node accurately predicted metastatic disease in the axilla. IHC studies failed to detect any additional micrometastases. This diagnostic technique may provide treatment guidance for patients after neoadjuvant therapy.

Axilla↗
PubMed2001

Collaboration to implement smoking cessation guidelines during the childbirth continuum.

BACKGROUND: Smoking during pregnancy has been linked with such negative outcomes as increased risk for spontaneous abortions, low birth weight, and perinatal and neonatal mortality. In spring 1998 three leading health care systems in San Diego initiated the Trilateral Partnership ("the Partnership"), whose mission is to improve the health and well-being of children. The Partnership chose tobacco control in pregnant women and their families as its first initiative. PROGRAM COMPONENTS-YEAR ONE (1999): Three interventions were developed: intervention by the prenatal care provider, initiation of a referral process to telephone counseling for pregnant women, and intervention for women reporting spontaneously quitting smoking. To date, 83% of the more-than 20,000 women who have been seen in prenatal screening in 28 months counted themselves as nonsmokers. Eleven percent of the women reported they independently stopped smoking once they learned they were pregnant. Six percent reported that they were still smoking. Twenty-three percent of the women reported living in a household with other smokers. PROGRAM COMPONENTS-YEAR TWO (2000): Activity focused on continuing the previous components, hospital intervention for all new mothers at the time of delivery, pediatric intervention at the newborn's visits at 2 and 6 months of age, and development and refinement of a telephone protocol for new parents. ELEMENTS OF SUCCESS: The noncontroversial topic of encouraging smoking cessation during pregnancy was one that enhanced immediate buy-in by most individuals contacted to support and engage in the program. Strong commitment and financial support from three health care systems opened doors for the Smoke-Free Families staff and increased the program's visibility in the community.

Adult↗
PubMed2000

Fine-needle aspiration cytology of low-grade fibromyxoid sarcoma of the renal capsule (capsuloma).

We report on the fine-needle aspiration (FNA) findings of a low-grade fibromyxoid sarcoma arising from the renal capsule in a 70-yr-old male. Cytologic examination revealed a spindle-cell and myxoid lesion characterized by microtissue fragments of delicate spindle-shaped cells and thin-walled capillary-type channels enmeshed in metachromatically staining myxoid material, best appreciated in Diff-Quik-stained smears. The spindle cells had slightly elongated, bland, oval to tapered nuclei. Based on the FNA diagnosis, the renal mass was resected, which revealed a hypocellular to moderately cellular, spindle-shaped neoplasm showing alternating hypercellular fibrous foci with hypocellular myxoid areas arranged in a swirling growth pattern, characteristic of low-grade fibromyxoid sarcoma. We believe that this is the first report of a low-grade fibromyxoid sarcoma arising in the renal capsule (capsuloma), as well as the first capsuloma diagnosed by FNA biopsy. Differential diagnoses of other sarcomas arising from the kidney and nearby retroperitoneal region are discussed, as well as other entities that might enter into the differential diagnosis of this low-grade sarcoma.

Aged↗
PubMed2000

Tubular adenomas of the breast: imaging findings with histologic correlation.

OBJECTIVE: The purpose of this study is to describe the imaging features of tubular adenomas, which are rare benign breast tumors usually found in women younger than 35 years old. CONCLUSION: In young women, tubular adenomas can look like noncalcified fibroadenomas on mammography and sonography. In older women, tubular adenomas may resemble malignant masses with microcalcifications. Awareness of these findings may help in assessing concordance between imaging and histologic findings after percutaneous core biopsy of these rare lesions.

Adenoma↗
PubMed1998

Prolonged survival in a patient with sinonasal teratocarcinosarcoma with cranial extension. Case report.

Sinonasal teratocarcinosarcoma is a rare malignant neoplasm characterized by the combined histological features of carcinosarcoma and teratoma. The primary symptoms of this tumor are usually nasal obstruction and epistaxis, and a nasal cavity mass is the most common clinical finding. The authors describe an exceptionally rare case in which the patient presented with massive intracranial extension and exhibited confusion as an initial symptom. He subsequently underwent combined radical surgery and radiation therapy and has remained free of disease for 31 months. The surgical approach to the lesion, histological features, and clinical course are detailed.

Aged↗
PubMed1993

Case report 790. Mesenchymal chondrosarcoma of the sacrum.

We have presented a case of mesenchymal chondrosarcoma of the sacrum in a 20-year-old woman. We have emphasized that CT and MR are the best imaging modalities for the assessment of the neoplasm and the surgical decision-making process. Histologic study is mandatory for diagnosis of the tumor, with its characteristic dual pattern of chondroid tissue and undifferentiated mesenchymal cells. The rarity of the neoplasm, its deep pelvic location and nonspecific symptomatology led to a late diagnosis and an unfortunate but necessary sacral amputation resulting in bladder and bowel functional sequelae.

Adult↗
PubMed1991

Four cases of trisomy 9p syndrome with particular chromosome rearrangements.

The authors present four children, two males and two females, with a 9p duplication, derived from various chromosome rearrangements, diagnosed using clinical, cytogenetic and biochemical evaluations. In particular, GALT dosage allowed them to define with accuracy the different chromosome break-points.

Chromosomes, Human, Pair 9↗
PubMed1987

Development of hepatic cholestasis and fibrosis in patients with massive loss of intestine supported by prolonged parenteral nutrition.

We studied the effect of 1 yr of parenteral nutrition on liver function tests and, when indicated, liver histology and ultrastructure of 18 patients with no (n = 6), modest (n = 6), and massive (n = 6) loss of intestine. The resection was for Crohn's disease and infarction, respectively. The liver function tests remained normal in all patients with no loss and modest loss of intestine. Four patients with massive loss of intestine, 4-10 mo after initiation of parenteral nutrition, began to develop progressive, marked increases in serum alkaline phosphatase (2-10 times normal), glutamic oxaloacetic transaminase (7-20 times normal), and glutamic pyruvic transaminase (5-14 times normal) activity levels, and bilirubin concentration (5-22 times normal). Light microscopic examination of liver showed cholestasis, bile ductular proliferation, periportal inflammation, fibrosis, and mild steatosis. Electron microscopic examination of liver showed cholestasis with nonspecific organelle changes. None of the patients had any evidence of extrahepatic obstruction. Our data suggest that massive loss of intestine is a contributing factor to hepatic cholestasis and fibrosis in patients maintained on prolonged parenteral nutrition.

Cholestasis↗
PubMed1987

Why is there a left side underestimation in rod bisection?

Subjects set the extremities of a horizontal rod to appear equidistant from a central reference point, with or without central fixation. On either side, the contrast (salience) of the rod against the background was high or low. Extents to the left were set smaller than those to the right, an effect (LSU) which was stronger with central fixation, indicating that both hemispatial and anatomical pathway factors contribute. Reduced salience on the left increased rather than decreased the LSU, indicating the importance of attentional factors.

Adult↗
PubMed1986

Tactual-kinesthetic matching of horizontal extents by the long-term blind: absence or reversal of normal left-side underestimation.

Ten adults, who were blind from infancy or childhood, laterally slid a horizontal rod within a short length of pipe located at the body midline, until the rod extremities were tactually-kinesthetically judged to be equidistant from the ends of the pipe. Whereas sighted subjects normally set the left extremity of the rod closer to the midline than the right irrespective of arm posture, crossed or uncrossed, blind subjects, especially those blind from birth showed trends in the opposite direction. The role of vision is discussed with respect to the development and expression of asymmetries relating to the coding of extracorporeal space.

Adult↗
PubMed1986

Leftwards error in bisecting the gap between two points: stimulus quality and hand effects.

Subjects attempted to bisect the gap between two LEDs; these differed from each other in brightness, stimulus duration, onset/offset (a) synchronies, and in continuous or flashing mode of presentation. There was a systematic bias to the left, especially with the left hand, indicating a motor contribution to this perceptual task. A brief, faint or flashing LED attracted the subjective midpoint, perhaps because of increased processing demands; indeed the general leftwards bias was attributed to a greater visuospatial processing capacity in the right hemisphere. Leftwards bias was rather greater when central fixation was maintained, indicating that hemispatial mechanisms may be more important than anatomical connectivities. The technique may be useful for understanding and treating unilateral neglect.

Attention↗
PubMed1985

Bisecting rods and lines: effects of horizontal and vertical posture on left-side underestimation by normal subjects.

In Experiment I normal subjects performed the classical clinical line-bisection task, and demonstrated a left-side underestimation. In Experiment II subjects maintained fixation upon a central position and adjusted a rod passing through this fixation point so that both extremities were judged equal. The left-side underestimation was very much greater under these conditions, but was considerably reduced when retinal and gravitational coordinates were dissociated by making the subjects lie horizontally on one or other side. Subjects then demonstrated greater left-side and top-half underestimation when lying on the left than on the right side. Gravitational coordinates and the apparent locus of events in extrapersonal space are determinants of perceptual asymmetries at least as important as anatomical connectivities.

Adult↗
PubMed1985

Alternative dual system network estimators.

"When there are two or more data systems and none of them enumerates the population at an acceptable completeness level, concern about the bias due to underenumeration suggests an estimator which makes joint use of data compiled by the combined imperfect data systems. Conventional dual system estimators are based on the existence of two separate data collection systems. Dual system network estimators assume a main survey and a follow-up quality check survey. The main survey adopts a multiplicity counting rule that combines two mutually exclusive partial counting rules." Three dual system network estimators are presented. "One was previously proposed by Sirken (1979) and is the natural analogue of the conventional dual system estimator. The two other estimators are proposed as potential improvements, although neither of them is the natural analogue of the conventional dual system estimator. The design effects of the three estimators are compared analytically and empirically with one another, and with those of the single system conventional and network estimators." (summary in FRE)

Data Collection↗
PubMed1984

A moving video window or a mask yoked to eye movements: experiments on letters, words and biological movement with prolonged hemifield stimulation.

We describe the first use of a new technique, which permits prolonged presentation to one or other visual field of complex, realistic, "ecologically valid" stimuli. An infrared eye movement transducer is linked to a visual display such that an electronic mask (of adjustable dimensions) or, alternatively, a "window" can be made to move as consequence of eye movements. The mask can be made to move exactly with the initiating eye movement, or with positive gain, or in the opposite direction (with or without gain), or in both directions simultaneously ("scissoring"). Alternatively, the apparatus can be set to blank the entire display should an eye movement occur with an excursion greater than a preset criterion level. The display itself can be either computer generated or can consist of a pre-recorded video film. We report preliminary findings with this apparatus. When subjects detected a letter target in a three-by-three letter matrix of laterally presented letters, exposure durations from 50 msec to 400 msec showed consistent right visual field (RVF) superiorities. (Nor was there any evidence of left visual-field, LVF, superiorities at very brief exposures as others have claimed.) Equally strong RVF superiorities also appeared when subjects decided whether or not two simultaneously and laterally presented (for 500 msec) words rhymed, the word pairs being phonologically and orthographically similar (DOWN-GOWN), phonologically similar and orthographically distinct (FARE-HAIR), phonologically distinct and orthographically similar (MOWN-DOWN), or both phonologically and orthographically distinct (FORT-GOAT). Finally, Johansson's (1973, 1976) biological movement procedure was adapted for lateral viewing, with unlimited exposure times. However, the predicted LVF superiority did not eventuate, when subjects decided whether moving points of light, attached to the limbs of darkened walkers, were worn by males or females. Further possible applications of this technique are described for normal and clinical subjects.

Eye Movements↗
PubMed1983

Head and body space to left and right, front and rear--II. Visuotactual and kinesthetic studies and left-side underestimation.

We report seven experiments involving unimanual or bimanual tactual or visuotactual judgments with horizontally or vertically disposed rods, performed in left or right hemispace, in the context of Bowers and Heilman's (Neuropsychologia 18, 491-498, 1980) hemispace hypothesis. We were only able to weakly confirm their finding of a left hemispace superiority, though either hand was more accurate when in its own hemispace. However, their observation of a left pseudoneglect phenomenon was supported and extended: we found that the left hand underestimates relative to the right, and that there may be left hemispace underestimation which is lost with 90 degree head turns, when horizontal extents are underestimated in the direction of the head turn.

Cerebral Cortex↗