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Biomedical subjects

K Fox

Publications and source records attributed to K Fox.

282 records · Page 16Linked to original sources
PubMedDate not supplied

Imaging high-resolution structure of GFP-expressing neurons in neocortex in vivo.

To detect subtle changes in neuronal morphology in response to changes in experience, one must image neurons at high resolution in vivo over time scales of minutes to days. We accomplished this by infecting postmitotic neurons in rat and mouse barrel cortex with a Sindbis virus carrying the gene for enhanced green fluorescent protein. Visualized with 2-photon excitation laser scanning microscopy, infected neurons showed bright fluorescence that was distributed homogeneously throughout the cell, including axonal and dendritic arbors. Single dendritic spines could routinely be resolved and their morphological dynamics visualized. Viral infection and imaging were achieved throughout postnatal development up to early adulthood (P 8-30), although the viral efficiency of infection decreased with age. This relatively noninvasive method for fluorescent labeling and imaging of neurons allows the study of morphological dynamics of neocortical neurons and their circuits in vivo.

Aging↗
PubMedDate not supplied

Dermatoglyphics in sudden infant death syndrome.

An analysis of digital and palmar dermatoglyphic patterns was conducted in 173 victims of the sudden infant death syndrome (SIDS). The results expose four dermatoglyphic regions with pattern frequencies differing from those in a control population. These are an excess of Sydney creases, hypothenar patterns, open fields (with fewer vestiges) in interdigital region IV, and arches on all digits (females only). These findings indicate a genetic or early intrauterine environmental influence in SIDS infants. An increased incidence of dysmorphism and anomalies including recognition of specific syndromes support this contention. One could speculate that these dermatoglyphic deviations reflect specific genotypes and/or phenotypes particularly vulnerable to postnatal challenges. Differences in multiple dermatoglyphic categories support the concept of heterogeneity of the SIDS population and multicausality of SIDS.

Boston↗
PubMedDate not supplied

Cardiac enzymes.

Explore the source record for details and available documents.

Creatine Kinase↗
PubMedDate not supplied

Long-term outcome after postmastectomy radiation therapy for breast cancer patients at high risk for local-regional recurrence.

PURPOSE: Postmastectomy radiation therapy is often recommended for patients at high risk for local-regional recurrence after mastectomy. However, long-term outcomes after radiation therapy are not well described. PATIENTS AND METHODS: Between 1977 and 1992, 221 patients at high risk for local-regional recurrence of breast cancer after mastectomy were treated with radiation therapy, with or without adjuvant systemic therapy. Patients were classified as high risk because of T3 or T4 tumors (14%), positive lymph nodes (29%), close or positive margins of resection (15%), or multiple risk factors (39%); 4% did not meet current criteria for radiation therapy. The median age of patients was 51 years. Radiation therapy consisted of 45 to 50.4 Gy to the chest wall in 1.8 to 2.0 Gy fractions. The regional lymph nodes were treated in 187 patients (85%). There were 151 patients (68%) who received adjuvant chemotherapy. Patients who received chemotherapy were younger (median age, 48 years vs 64 years) and had more positive lymph nodes (median, 5 vs 1) than patients not receiving chemotherapy. Adjuvant hormonal therapy was utilized in 116 patients (53%). The median follow-up was 4.3 years. RESULTS: The actuarial 10-year local-regional failure rate was 11% (95% CI: 6.5% to 16.7%). The site of first failure was distant metastases in 75 patients (34%), local-regional recurrence in 11 patients (5%), and both sites in three patients (1%); 60% had no evidence of disease at last follow-up. Of the patients who presented with local-regional recurrence as first failure, nine patients (82%) subsequently developed metastatic disease. The median time to local-regional first failure was 1.3 years. The median time to distant metastases after local-regional first failure was 0.3 years. DISCUSSION: Postmastectomy radiation therapy is associated with an 89% rate of local-regional control in this high-risk population. Patients who experience a local-regional recurrence after radiation therapy are at a very high risk for metastatic disease. Radiation therapy after mastectomy is recommended to optimize local-regional control for high-risk breast cancer patients.

Actuarial Analysis↗
PubMedDate not supplied

Analysis of outcomes for high-risk breast cancer based on interval from surgery to postmastectomy radiation therapy.

PURPOSE: The success of adjuvant chemotherapy has prolonged the interval between surgery and postmastectomy radiation therapy for high-risk breast cancer patients. The purpose of this study is to determine whether a delay in radiation therapy after mastectomy results in an increased risk of local-regional recurrence of breast cancer. MATERIALS AND METHODS: A retrospective review was performed of the University of Pennsylvania database of 221 patients with high-risk breast cancer treated with postmastectomy radiation therapy between 1977 and 1992. The surgery to postmastectomy radiation therapy time interval was 2 months or less in 82 patients (37%), 2.1 to 6 months in 50 patients (23%), and greater than 6 months in 89 patients (40%). Adjuvant chemotherapy was utilized in 151 patients (68%). The median follow-up was 4.3 years after postmastectomy radiation therapy. RESULTS: Because the three groups showed significant differences for a number of prognostic factors, outcomes are reported in terms of local-regional recurrence only and not survival. The actuarial rate of local-regional recurrence at 8 years was 13% for patients with a surgery to radiation therapy interval of 2 months or less, 4% for those with an interval of 2.1 to 6 months, and 12% for those with an interval of greater than 6 months. A similar analysis performed for 4 months or less versus greater than 4 months between surgery and postmastectomy radiation therapy showed no difference in local-regional recurrence (11% versus 10%, respectively). CONCLUSIONS: A delay in the institution of postmastectomy radiation therapy in favor of the prolongation of chemotherapy for high-risk breast cancer patients does not adversely affect outcome for local-regional recurrence at 8 years.

Breast Neoplasms↗
PubMedDate not supplied

Parasitic infections in young Jamaicans in different ecological zones of the island.

Data are presented for the first country wide prospective study on gastrointestinal tract parasitic infections done in Jamaica. Samples from 2,947 young Jamaicans drawn from all ecological zones and from all parochial divisions of the island were analyzed. Pica was practised by 8.6%. Generally, prevalence of organisms was as follows: Trichuris trichiura (12.3%), Ascaris lumbricoides (9.5%), hookworm (2.2%), Strongyloides stercoralis (0.3%), Giardia lamblia (6.3%) and Entamoeba coli (7.7%). Several other spp. of protozoans were recorded. Prevalence of A. lumbricoides, T. trichiura and Necator americanus was significantly greater in upland than in lowland (both urban and rural), while the situation was reversed for G. lamblia-infections. Greatest variations were age-related. A. lumbricoides and T. trichiura reached peak prevalence of 15.3 and 20.5% respectively in 5-9-year-olds, while hookworm peaked later at 15-19 years of age. Suggestions are made for a national and even regional antihelminthic program for the mass treatment of pre- and primary school age children.

Adolescent↗
PubMedDate not supplied

Analysis of verbal behavior between physicians and geriatric patients.

This study was designed to analyze communication patterns between older patients and physicians by an in-depth examination of linguistic aspects of the interactions, including utterance form, process, and content variables. Sixteen family medicine residents were videotaped individually interviewing one of four simulated female patients. Verbal behavior was analyzed in detail using categories from linguistic studies. Residents were divided into High and Low Information groups. Significant differences in interviewing style were found between groups in categories of: Closed (High = 62.25, Low = 35.88), Compound (High = 11.63, Low = 2.00), and Reflective (High = 20.13, Low = 10.13) Questions; Direct (High = 33.50, Low = 25.00) and Positive (High = 9.25, Low = 3.88) Answers; Added Information (High = 15.75; Low = 9.38); Listener Responses (High = 57.38, Low = 41.50); and Appropriate Turn-Taking (High = 66.63, Low = 48.38). There seems to be a clear difference between what is taught in medical schools about interviewing and the interviewing techniques used by residents in the actual practice of medicine. High information doctors combined a style of closed and combined questions with considerable facilitation and respect for the patient.

Aged↗
PubMedDate not supplied

Improving outcome after acute myocardial infarction: what is the role of ACE inhibitors?

Acute myocardial infarction continues to be the number 1 killer in industrialised countries. While the more widespread use of thrombolytic therapy has made a dramatic impact on patient survival, changes in long-term prognosis after discharge from hospital have not improved radically and 5-year mortality remains at over 30%. The single most important determinant of survival in the long term is left ventricular function. The process of ventricular dilatation and remodelling begins early after infarction. While such changes may initially go unrecognised clinically, without intervention progressive functional impairment will ensue and the majority of patients will develop signs and symptoms of heart failure, which carries a worse prognosis than many forms of cancer. ACE inhibitors act on both the haemodynamic and neurohormonal mechanisms in heart failure. Several large-scale clinical trials have clearly demonstrated that early use of these agents in stable patients who are not hypotensive or in cardiogenic shock can reduce significantly the development of heart failure and death. A strategy for the early initiation of ACE inhibitor therapy is proposed to improve survival in AMI patients.

Angiotensin-Converting Enzyme Inhibitors↗
PubMedDate not supplied

The rat Nb2 lymphoma: a novel model for tumor progression.

Tumor progression of cancers is manifested by phenotypic property changes including development of hormone/growth factor independence and metastatic ability. The progression results from acquired genomic alterations leading to clonal heterogeneity and outgrowth of more aggressive and therapy-resistant sublines. Previously, a cultured rat "Nb2 lymphoma" cell line was established, whose viability depends critically on the hormone, prolactin, acting as the principal growth factor. By prolactin starvation, prolactin-independent sublines were generated which possessed the parent karyotype plus extra acquired chromosomal changes (clonal evolution). In this study, the parent line (Nb2-U17) and a cloned subline (SFJCD1) were compared for metastatic ability using single s.c. tumor transplants in Noble rats. Rats (22) bearing Nb2-U17 tumors showed no evidence of metastases at autopsy, even when tumors at implantation site reached a size of 9 cm (length + width). In contrast, rats (19) bearing SFJCD1 tumors showed multiple metastases (liver, kidney) when transplants exceeded 5 cm. This difference in metastatic ability may be related to the acquisition of an inversion in chromosome 1, i.e. inv(1)(q31q41). The 1q41 locus is adjacent to the reported H-ras-1 proto-oncogene locus (1q41-q42). In another subline, tetraploidization (flow cytometric analysis, karyotyping) occurred spontaneously following prolonged culturing (20 mo). Together, the parent Nb2 lymphoma line and its clonal derivatives provide a novel system for studying cellular and molecular mechanisms underlying tumor progression to the metastatic phenotype.

Animals↗