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Biomedical subjects

J Tucker

Publications and source records attributed to J Tucker.

At least 55 records · Page 3Linked to original sources
PubMed1997

Eosinophilic colitis presenting as a left-sided colocolonic intussusception with secondary large bowel obstruction: an uncommon entity with a rare presentation.

Eosinophilic gastroenteritis is a quite uncommon clinical entity usually involving the stomach or small bowel. Occasionally, the colon is involved. We have encountered a case of eosinophilic colitis leading to a left-sided colocolonic intussusception and subsequent large bowel obstruction. This is a unique presentation that, to our knowledge, has not been previously reported. We present our case in detail as well as a review of the literature to better understand this rare clinical entity.

Adult↗
PubMed1996

Study design and baseline characteristics of the study to evaluate carotid ultrasound changes in patients treated with ramipril and vitamin E: SECURE.

Atherosclerotic cardiovascular disease remains a major cause of mortality and morbidity in most developed countries. Experimental and clinical evidence suggests that angiotensin-converting enzyme inhibitors and vitamin E therapy may retard the atherosclerotic process; however, definitive proof in humans is lacking. The Study to Evaluate Carotid Ultrasound Changes in Patients Treated with Ramipril and Vitamin E (SECURE) is designed to assess the effects of ramipril--an angiotensin-converting enzyme inhibitor, at 2 doses: 2.5 mg daily (which has little effect on lowering blood pressure) and 10 mg daily--and the antioxidant vitamin E, 400 IU daily, on atherosclerosis progression in 732 patients using a factorial 3 x 2 study design. High-risk patients with a documented history of significant cardiovascular disease or with diabetes and additional risk factors were enrolled and will be followed for 4 years. The extent and progression of atherosclerosis are assessed noninvasively by B-mode carotid ultrasonography. The SECURE trial is a substudy of the larger Heart Outcomes Prevention Evaluation (HOPE) study of 9,541 high-risk patients evaluating the effects of ramipril and vitamin E on major cardiovascular events (cardiovascular death, myocardial infarction, and stroke). The 2 studies are complementary. Whereas HOPE is expected to provide information on major clinical outcomes, SECURE will shed light on the mechanisms by which these effects may be mediated.

Aged↗
PubMed1996

Purification of a rat neurotensin receptor expressed in Escherichia coli.

A truncated rat neurotensin receptor (NTR), expressed in Escherichia coli with the maltose-binding protein fused to its N-terminus and the 13 amino acid Bio tag fused to its C-terminus, was purified to apparent homogeneity in two steps by use of the monomeric avidin system followed by a novel neurotensin column. This purification protocol was developed by engineering a variety of affinity tags on to the C-terminus of NTR. Surprisingly, expression levels varied considerably depending on the C-terminal tag used. Functional expression of NTR was highest (800 receptors/cell) when thioredoxin was placed between the receptor C-terminus and the tag, indicating a stabilizing effect of the thioredoxin moiety. Several affinity chromatography methods were tested for purification. NTR with the in vivo-biotinylated Bio tag was purified with the highest efficiency compared with NTR with the Strep tag or a hexa-histidine tail. Co-expression of biotin ligase improved considerably the in vivo biotinylation of the Bio tag and, therefore, the overall purification yield. Proteolysis of the NTR fusion protein was prevented by removing a protease-sensitive site discovered at the N-terminus of NTR. The ligand binding properties of the purified receptor were similar to those of the membrane-bound protein and the native receptor. The scale-up of this purification scheme, to provide sufficient protein for biophysical studies, is in progress.

Amino Acid Sequence↗
PubMed1996

Associative learning in patients with cerebellar ataxia.

It has been claimed that patients with cerebellar pathology are impaired at associative learning. Patients with cerebellar ataxia (n = 7) were taught a visual-motor associative task. The task was chosen so as to allow comparisons with data currently being collected on the effects of cerebellar lesions on associative learning in monkeys. As a group the patients were as impaired at learning the task as a group of 8 patients with Huntington's disease. When each patient was individually matched with a control of the same age and IQ, some patients with cerebellar ataxia were found to be clearly impaired, but 2 were not. Of the 4 patients who were most clearly impaired, 2 had brainstem pathology and 2 did not. The relevance of these findings is discussed in relation to views concerning the functions of the cerebellum.

Adult↗
PubMed1996

Medicare health maintenance organizations. An industry analysis for the elderly in the USA.

Provides a review and analysis of Medicare health maintenance organizations in the USA. The Porter model of industry structure is used. Discusses the issues of suppliers, buyers, market entry and substitutes. Indicates there is currently no intense rivalry among Medicare risk-based HMOs. However, the Porter model reveals crucial information regarding the forces which drive industry competition. Trends in the field of managed care and Medicare financing continue to be a real challenge regarding future research.

Aged↗
PubMed1996

Evaluation of HER-2/neu (c-erbB-2) oncogene expression in whole organ sections of supraglottic squamous cell carcinoma.

Adequate pathologic material and careful clinical follow-up are prerequisites for the analysis of the expression of particular oncogenic proteins that are prognostically important in squamous cell carcinoma of the larynx. The Gabriel Tucker, Jr, Collection of 150 whole organ specimens allows for the potential immunohistochemical study of the entire tumor. Sections from 32 supraglottic carcinomas were studied immunohistochemically for the presence of HER-2/neu (c-erbB-2) oncogene expression. Long-term follow-up data were available in all cases to assist in determining the prognostic significance of the specified oncogene in supraglottic squamous cell carcinoma. Our study revealed that joint presentation of immune staining for c-erbB-2 and positive lymph node status was significantly associated with distant metastasis (p=.00760).

Adult↗
PubMed1996

The costs of alternative types of routine antenatal care for low-risk women: shared care vs care by general practitioners and community midwives.

OBJECTIVES: To compare the costs to the health service, women and their families of routine antenatal care provided by either traditional obstetrician-led shared care or general practitioner (GP)/community midwife care. METHOD: A multicentre randomized controlled trial in 51 general practices linked to nine maternity hospitals in Scotland: 1667 low-risk pregnant women provided information on costs to the health service. 704 of these women provided information on non-health service costs. RESULTS: GP/midwife antenatal care was found to cost statistically significantly less than shared care. This was the case for investigations carried out at routine antenatal visits (GP/midwife = 87.25 Pounds, shared care = 91.15 Pounds, P = 0.05), staffing costs at routine antenatal visits (GP/midwife = 127.76 Pounds, shared care = 131.09 Pounds, P = 0.001), and non-health service costs incurred by women and their companions (GP/midwife = 118.53 Pounds, shared care = 133.49 Pounds, P = 0.001). While non-routine care in the GP/midwife arm of the trial costs less than in the shared care arm, the difference was not statistically significant (GP/midwife = 83.74 Pounds, shared care = 94.43 Pounds, P = 0.46). The total societal cost of antenatal care was 417.28 Pounds per women in the GP/midwife arm of the trial and 450.19 Pounds in the shared care arm of the trial. This difference was statistically significant (P < 0.001). The application of sensitivity analysis did not change these results. CONCLUSIONS: GP/midwife antenatal care is a satisfactory option for low-risk pregnant women in Scotland provided that clinical outcomes and women's satisfaction are at least the same as those of women with shared care.

Cost Savings↗
PubMed1996

The effect of previous lower abdominal surgery on performing the total extraperitoneal approach to laparoscopic herniorrhaphy.

At Georgia Baptist Medical Center in Atlanta, GA, we adopted the total extraperitoneal approach (TEPA) to laparoscopic herniorrhaphies because of the concerns of potential early and late complications associated with entering the abdominal cavity. In our institution, the TEPA has compared favorably with the transabdominal approach, with lower complication and recurrence rates. There has been concern, however, in performing the TEPA in patients with previous lower abdominal surgery. The question has been raised that there is increased risk of complications in these patients. From June 1993 to May 1994, we performed 247 laparoscopic herniorrhaphies in 192 patients using the TEPA. Of these, 55 hernias were repaired in 45 patients with previous lower abdominal surgery. Overall retrospective results showed a slightly higher complication rate (23.1% vs 11.3%) and slightly higher recurrence rate (1.8% vs 0%) in the patients with previous surgery over those without. Although these differences are not statistically significant, it is important to keep these risks in mind when selecting the appropriate hernia repair for each patient.

Adolescent↗
PubMed1995

Allogeneic lymphocyte proliferation stimulated by small intestine-derived epithelial cells.

It has been more difficult to prevent intestinal allograft rejection than rejection of other solid organ transplants. Epithelial cells in the small intestine have the potential to actively participate in graft rejection because they constitutively express MHC class II antigens. The present study examined the ability of intestinal epithelial cells (IEC) to stimulate allogeneic T cells in vitro using one-way MLC. IEC from jejunum and ileum of ACI rats (RT1a) were used as the stimulator cells; purified T lymphocytes from Lewis rats (RT11) were used as the responder cells. Freshly isolated IEC were poor stimulators of naive allogeneic T lymphocytes. However, IEC induced a strong proliferation of primed allogeneic T lymphocytes, and this response could be blocked by anti-MHC class II mAb (OX-4). IEC stimulated a vigorous proliferation of naive T cells when co-cultured with (1) macrophages syngeneic with responder T lymphocytes, (2) supernatants of LPS-stimulated macrophages, or (3) a combination of IL-1 and IL-6. We conclude that MHC class II positive IEC require soluble costimulatory factors to fully activate naive allogeneic T cells. Immune stimulation by enterocytes may be one of the reasons why it is so difficult to prevent intestinal allograft rejection. Strategies that block interactions among IEC, macrophages, and lymphocytes may reduce the immunogenicity of small bowel transplants.

Animals↗
PubMed1995

Preparation and characterization of RNA standards for use in quantitative branched DNA hybridization assays.

RNA standards were developed for use in quantitative hybridization assays such as the Quantiplex HCV RNA Assay and Quantiplex HIV RNA Assay, which are based on branched DNA signal amplification. In vitro transcripts ranging in size from 0.5 to 9.4 kb were prepared and purified by phenol extraction following gel electrophoresis or column chromatography. Aliquots of the transcripts were digested to nucleosides and phosphate and then quantified by phosphate analysis against the U.S. National Institute of Standards and Technology phosphate standard. The quantitation was checked by OD260 and by either hyperchromicity or isotopic tracer analysis. The quantitation of each lot of RNA agreed within 20% by the three methods. The reproducibility of the methods was tested by preparing a total of 13 lots of standard RNAs. The average percentage full-length RNA of the 13 lots was 82%, with a range of 59 to 97%. The standard RNAs were used to test the ability of the branched DNA hybridization assay to quantify all target RNAs accurately regardless of size or slight variations in sequence. Standard Hepatitis C virus (HCV) RNAs of 1.3, 2.2, and 3.2 kb showed that size has no detectable effect on quantitation in the branched DNA hybridization assay. Three different lots of standard 3.2-kb HCV RNA were serially diluted and quantified over a thousand-fold range in the branched DNA hybridization assay. The average signal per attomole of target varied by less than 20% among the 3 lots. Standard HCV RNA transcripts were also prepared from clones of HCV subtypes 1b and 3a to study the effects of target sequence diversity and probe design on quantitation by hybridization.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1995

Reconsidering a paradigm: the spread of supraglottic carcinoma to the glottis.

This study was performed to evaluate the spread of supraglottic carcinoma to the glottic level. Whole organ sections of total laryngectomy specimens from 37 patients with previously untreated supraglottic carcinomas were reviewed retrospectively. Of the 37 specimens, 20 (54%) were noted to have extension of cancer to the glottic level. A significant relationship was noted between glottic extension and abnormal cord motion (P = .0002). A statistically significant trend was noted for the relationship between inferior extension along the supraglottic mucosa and glottic level extension (P < .0001). Contrary to the prevailing model of the spread of supraglottic carcinoma, in which there is a distinct barrier to spread at the ventricle, this analysis of selected supraglottic carcinomas revealed a continuum of spread from the supraglottic to the glottis.

Chi-Square Distribution↗
PubMed1994

Primary care.

Explore the source record for details and available documents.

Female↗
PubMed1994

Is antenatal care apportioned according to obstetric risk? The Scottish antenatal care study.

A retrospective cohort study of case records of antenatal care was carried out to describe and compare antenatal services in Scotland according to type of hospital and risk category of women. The study took place at 15 randomly selected maternity hospitals which were divided into teaching hospitals (n = 5), rural catchment hospitals (n = 2), and district general hospitals divided by size as those with 1000-1699 deliveries per year (n = 4), and those with > or = 1700 deliveries per year (n = 4). The subjects were 3574 (87.7 per cent) of 4069 eligible women who delivered in the last quarter of 1989 at these hospitals. Of those 3574, 19 per cent (675) were considered to be high risk at booking, 64 per cent (2899) continued low risk throughout their pregnancy and the remaining 17 per cent (608) changed from low risk to high risk during pregnancy. The main outcome measures were the number, timing, location and supervision of antenatal visits and antenatal admissions in relation to hospital types and obstetric risk categories, and adverse pregnancy outcomes in relation to risk categories. It was found that 97 per cent of all women had care shared by general practitioner (GP) and hospital specialist agreement. The majority (64 per cent) of antenatal visits took place away from the hospital of delivery, with GPs responsible for the largest proportion of all antenatal visits (43.5 per cent) compared with specialist hospital doctors (36 per cent) and midwives (11.5 per cent). Wide variations in the use of different personnel groups to deliver antenatal care were observed between hospitals, particularly in the use of midwives to supervise visits (4-34 per cent). The median number of antenatal visits was 14 (mean 13.9, SD 3.9). Within hospital types the differences in the mean number of antenatal visits between the three risk categories were small (one to two visits) and the direction inconsistent. In all types of hospital, outset high-risk women and those who changed to high risk were more likely to have hospital admission than those who continued as low risk. Significantly more women in the high-risk categories experienced adverse pregnancy outcomes than women who continued at low risk.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1994

Is breast-feeding in infancy associated with adult longevity?

OBJECTIVES: The purpose of the study was to determine whether breast-feeding is associated with increased longevity or cause-specific survival. METHODS: Teachers throughout California identified intellectually gifted children as part of a prospective study begun in the 1920s by Lewis Terman. Information on breast-feeding was available on 1170 subjects, who have been followed for more than 65 years. RESULTS: Survival analysis (Cox proportional hazards model) indicated that breast-feeding was associated with increased longevity, even after adjustment for age at baseline, birthweight, infant health, and childhood socioeconomic status, but only among men, and the association was not significant (P = .15). Neither cardiovascular disease nor cancer survival was significantly associated with duration of breast-feeding for either sex. Survival from deaths due to injuries was positively associated with breast-feeding after adjustment (P = .03) and demonstrated a clear gradient with duration, but only among men. CONCLUSIONS: Overall, the present study does not provide strong evidence that breast-feeding is associated with adult longevity. The reduced risk of death from injury may reflect chance, in that the association was significant only for men, or it may reflect psychosocial correlates of breast-feeding practices.

Aged↗
PubMed1993

CD32C (Fc gamma RIIC) mRNA expression and regulation.

The cell surface expression of the CD32 receptors for the Fc portion of immunoglobulin G (Fc gamma RII-CD32) is regulated by agents such as phorbol esters (PMA) and cytokines. In this study, we investigated the effects of PMA and interferon-gamma (IFN-gamma) on the expression of CD32C mRNA in U937 cells. When U937 (CD32+) cells are incubated with either PMA or IFN-gamma a significant enhancement of CD32C mRNA expression is observed with maximum enhancement at 18 hrs post-PMA and IFN-gamma addition. The addition of actinomycin D (ActD), a transcriptional inhibitor, together with either PMA or IFN-gamma diminishes the enhanced levels of CD32C mRNA to the basal levels, indicating that transcriptional regulation is involved in this modulatory process. The addition of cyclohexamide (CX), a protein synthesis inhibitor, to cultures undergoing stimulation with either PMA or IFN-gamma, increased the levels of CD32C mRNA synthesis suggesting that regulatory degradation proteins may be involved. The PMA and IFN-gamma stimulated CD32C mRNA is degraded within 2 hr post-stimulation and this degradation is delayed by the inhibition of de novo protein synthesis. These results, taken together with our previous studies of CD32A mRNA regulation in U937 cells stimulated with PMA, indicate that both the CD32A and C isomer mRNAs are rapidly degraded; however, CD32A and C isomer mRNAs are differentially regulated. At the optimal PMA dose, the time of mRNA stimulation of CD32A and C mRNA varies and the addition of CX to U937 cells together with PMA enhanced the levels of CD32C mRNA but had no effect on CD32A mRNA levels. These results imply that the differential regulation of the two CD32 isomers may result in differential function.

Antigens, CD↗