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Biomedical subjects

J Baker

Publications and source records attributed to J Baker.

At least 217 records · Page 12Linked to original sources
PubMed1990

Gallstone composition in relation to buoyancy at oral cholecystography.

Although it is recognized that some gallstones float at oral cholecystography, the reasons for this are not known. To determine how stone type and composition are related to stone buoyancy, the authors analyzed gallstones from 90 patients in the National Cooperative Gallstone Study. Seventeen patients had floating and 73 had nonfloating radiolucent stones at oral cholecystography. Stone analysis showed that all 17 floating stones were cholesterol stones; 64 of the nonfloating stones were cholesterol stones, while nine were pigment stones. The cholesterol contents of floating and nonfloating cholesterol stones were similar, 90.4% +/- 1.7 and 87.0% +/- 1.2 of stone weight, respectively. The calcium salt content of the nonfloating cholesterol stones was 3.2% +/- 0.6, while that of the floating cholesterol stones was only 1.1% +/- 0.4 (P = .02). The results indicate that floating gallstones are cholesterol stones with a significantly lower calcium salt content than that of nonfloating cholesterol stones.

Cholecystography↗
PubMed1990

Colon transit scintigraphy in health and constipation using oral iodine-131-cellulose.

The purpose of the study was to assess if a new scintigraphic method for noninvasive assessment of colonic transit could differentiate between subjects with normal bowel transit and those with constipation. Eleven normal subjects and 29 constipated patients were given 4 MBq iodine-131-cellulose (131I-cellulose) orally and sequential abdominal scans were performed at 6, 24, 48, 72, and 96 hr from which total and segmental percent retentions were calculated. There were clear differences between the normal subjects and the constipated patients for the total percent retention at all time intervals, on a segmental basis in the right colon at 24 hr, and in all segments at 48 and 72 hr. Three-day urinary excretion of radioiodine was minimal; 2.4% +/- 1.2% (mean +/- s.d.) in constipated patients and 3.1% +/- 0.8% in normals, with approximately 75% occurring in the first day. The use of oral radiotracers in the investigation of constipation appears promising.

Administration, Oral↗
PubMed1989

Isolation of multiple types of plasminogen activator inhibitors from vascular smooth muscle cells.

Large arteries have a natural resistance to tumor cell invasion thought to be due to the production of protease inhibitors. Vascular smooth muscle cells (VSMC) representing the major cellular part of arteries were isolated from human aortas and grown in tissue culture. These cells were found to produce large amounts of inhibitors of plasminogen activators (PA). Fractionation of VSMC-conditioned medium by heparin-affigel chromatography separated three immunologically and functionally distinct PA inhibitors (PAI), namely PAI-1, PAI-2 and protease-nexin I. The three inhibitors were characterized by functional assays and immunoblotting. PA inhibitor 2 (PAI-2) had little affinity for heparin, whereas PA inhibitor 1 (PAI-1) bound to heparin and was eluted from the column at NaCl concentrations of 0.1 to 0.35 M. Protease-nexin I, eluted at NaCl concentrations of 0.5 M and higher. Most of the PAI-1 was present in the latent, inactive form. PAI-1 was further purified by ion exchange chromatography on a Mono-Q column. Partial sequencing of the purified PAI-1 confirmed its nature by matching completely with the sequence deduced from the cDNA nucleotide sequence of endothelial cell PAI-1. Thus, human VSMC produce all three presently known PAI and these can be separated in single heparin affinity purification step.

Amino Acid Sequence↗
PubMed1989

The specificity of a mouse monoclonal antibody to human aorta proteoglycans.

Mouse monoclonal antibodies to human aorta proteoglycans have been raised. A sensitive radioimmunoassay which can be employed to measure binding of proteoglycans to these antibodies is described. It offers advantages of simplicity and speed over other immunoassays currently employed for proteoglycan determination. One of the monoclonal antibodies, 6D2/B5, recognizes keratan sulfate-bound antigens (e.g. cartilage proteoglycans). Further work has indicated that this antibody is not specific for keratan sulfate, as brain sulfatide and the seaweed polysaccharide, fucoidan, also possess its epitope. The 6D2/B5 antibody can be of value in localizing and estimating keratan sulfate if additional biochemical criteria for keratan sulfate recognition are utilized.

Antibodies, Monoclonal↗
PubMed1989

Cardiac complications of aneurysm repair.

To assess the early morbidity and mortality from coronary artery disease (CAD), we reviewed the charts of 49 patients who had elective resection of infrarenal abdominal aortic aneurysms between September 1978 and February 1986 at the VA and LSU medical centers in Shreveport. On the basis of history, physical examination, and resting electrocardiogram, patients were divided into two groups--those with clinical evidence of coronary artery disease (group 1, n = 21) and those without clinical evidence of coronary artery disease (group 2, n = 28). End points measured were perioperative (30-day) myocardial infarction (MI) rate and death. A definite MI was diagnosed when an abnormally elevated CPK-MB was accompanied by a new electrocardiographic abnormality or a reversal of the normal LDH isoenzyme pattern. A possible MI was diagnosed when an elevated CPK-MB was the only abnormality. In group 1, one definite (4.5%) and two possible (9.5%) MIs occurred. In group 2, there were no definite or possible MIs. All cardiac events were discovered by measurements of cardiac enzymes, since none of the patients had cardiac symptoms. This retrospective study reveals a low incidence of clinically significant cardiac events after resection of abdominal aortic aneurysms, even in patients with clinical evidence of coronary artery disease. Prophylactic coronary artery bypass surgery does not appear to be necessary for most patients needing repair of an abdominal aortic aneurysm.

Aged↗
PubMed1989

The incidence and notification of measles in Australia.

The incidence of measles in Australia in 1986 was estimated as 43 per 100,000 population, high by the standards of countries where immunization levels are high, low by the standards of countries where immunization levels are low. It is estimated that only 5 per cent of cases are notified in New South Wales, one of only 2 States which require notification. The reasons for this, its significance and a possible remedy are discussed.

Australia↗
PubMed1989

The recruitment and retention of minority and disadvantaged allied health students.

Student recruitment and retention has been given high priority over the last several years. The School of Allied Health Sciences at the University of Texas Medical Branch at Galveston has been involved in recruitment and retention programs that have produced minority student enrollment of over 20% over the past seven years. The programs are supported by federal grants that have provided seed money to design, develop, and implement three specific recruitment and retention programs. These programs have assisted in enrolling over 575 minority students with a retention rate above 90%. Graduation, licensure, and certification rates have been at or above the majority population. These programs are adaptable at other allied health professions schools and have been used as models for several programs across the United States.

Data Collection↗
PubMed1989

Relative efficacy for radiation reducing methods in scoliotic patients.

Radiation dosages to sensitive organs in full spine radiography have in recent years been a concern of physicians as well as the general public. The spine is the prime target for exposure in scoliosis radiography, though the exposure usually necessitates irradiation of several radio-sensitive organs. In recent studies, various protection techniques have been used including various lead and aluminum filtration systems, altered patient positioning and varied tube-film distances. The purpose of this study was to evaluate the efficiency for radiation dosage reduction of three filtration systems used frequently in the chiropractic profession. The systems tested were the Nolan Multiple X-ray Filters, the Clear-Pb system and the Sportelli Wedge system. These systems were tested in seven configurations varying breast shielding, distance and patient positioning. All systems tested demonstrated significant radiation reductions to organs, especially breast tissue. The Clear-Pb system appeared to be the most effective for all organs except the breast, and the Sportelli Wedge system demonstrated the greatest reduction to breast tissue.

Bone Marrow↗
PubMed1989

Intraoperative autotransfusion in radical cystectomy for carcinoma of the bladder.

From 1984 to 1987, 49 patients with transitional cell carcinoma of the bladder underwent radical cystectomy during which intraoperative autotransfusion was used. Thirty-three patients were observed for a minimum of one year postoperatively; the mean and median follow-up periods in this group were 23.8 and 26.0 months. Twenty-nine of these 33 patients were alive at the time of reporting; 25 were alive with no evidence of disease, and seven had postoperative recurrence of disease, and seven had postoperative recurrence of tumor. Diffused metastatic disease compatible with intravascular dissemination of tumor during autotransfusion did not develop in any of the patients. Intraoperative loss of blood ranged from 400 to 4,000 milliliters; the mean was 1,497, and the median, 1,300 milliliters. The mean volume of autotransfused blood was 492 milliliters. Autotransfusion accounted for 40 per cent of the total transfusion requirements of the patients and proved to be cost effective for the entire study group. Fear of dissemination of tumor has limited the use of intraoperative autotransfusion during surgical procedures for carcinoma. Analysis of our data failed to define any evidence for dissemination of tumor caused by autotransfusion in patients who underwent radical cystectomy.

Adult↗
PubMed1988

Motor output to lateral rectus in cats during the vestibulo-ocular reflex in three-dimensional space.

The motor output to the lateral rectus eye muscle was studied in decerebrate cats with electromyographic recordings and in alert cats with multi-unit and single neuron recordings from abducens nucleus. The axis of rotation that produced maximal excitation of the lateral rectus was calculated from responses to rotations in many different stimulus orientations, and was found to lie near the axis of the horizontal semicircular canals, but pitched slightly nose down from the canal axis (4.6 degrees). The results from decerebrate and alert cats were in agreement. The dynamics of lateral rectus activation were quite similar in all planes. Responses at high frequencies were in phase with rotation velocity and responses lagged toward position phase as frequency and velocity were decreased. Differences in decerebrate cat low frequency responses to rotations with and without a sinusoidal gravitational stimulus implicated an otolith input to lateral rectus.

Abducens Nerve↗
PubMed1988

The role of anterior lumbar fusion for internal disc disruption.

Internal disc disruption is a syndrome of traumatically induced low-back pain arising from the intervertebral disc. The diagnosis is confirmed by abnormal discography with concordant pain reproduction at the affected level or levels. Thirty-four patients with internal disc disruption at one level were followed for an average of 29 months. Eighteen (53%) underwent anterior lumbar fusion at the L4-5 disc, 11 (32%) at the L5-S1 disc and the remainder at the L3-4 or L2-3 disc. Bank bone was used in all but seven patients for interbody fusion. Treatment was judged a success by the patient returning to work or normal activities and requiring either no medications or an antiinflammatory drug only. By the above criteria 25 patients (74%) had successful outcome of treatment. The average time to return to work or normal activities was 6.1 months. The overall union rate was 73% with an average time to union of approximately 12 months. Complications consisted of graft extrusion requiring revision and retrograde ejaculation. These occurred in one patient and were the only complications in the series. We concluded that disc excision and anterior interbody fusion is an effective treatment for internal disc disruption.

Adolescent↗
PubMed1988

Fructosamine concentrations in general population of Kawerau.

We measured fructosamine concentrations in nonfasted serum from 7094 residents (82.8% of the estimated population) of Kawerau, New Zealand, including 65 known diabetic patients (prevalence of 0.92%). Fructosamine results showed a trimodal frequency distribution, with cutting points corresponding to 5th and 95th percentile values. Forty-two diabetic individuals had levels that exceeded the 95th percentile. These individuals had more severe metabolic abnormalities, characterized by lower plasma C-peptide and elevated fasting plasma glucose concentrations. Mean fructosamine values also showed a significant increase with age and a highly significant age-ethnic interaction that paralleled the higher frequency of diabetes in older age groups and among elderly Maori people. However, as a screening method in the general population, fructosamine measurement was diagnostically deficient because of a weak correlation with serum albumin. Arithmetic correction for albumin concentration in the sample did not increase the diagnostic usefulness of the test.

Adult↗