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Biomedical subjects

J Barton

Publications and source records attributed to J Barton.

At least 19 recordsLinked to original sources
PubMed1992

Radiotherapy for pleomorphic adenoma of the parotid gland.

A study was made of 187 patients with parotid pleomorphic adenoma treated by radiotherapy. This followed surgery but with incomplete removal or tumor spillage. In the early years of the study radiotherapy was given by radium needle implant done usually at the time of surgery, but from the late 1960s beam-directed external radiotherapy with a head shell was used most commonly. A 3-field technique or wedge pair was the standard technique. The median age was 46 with nearly half the patients (87/187) aged between 40 and 60, and the ratio of women to men was 1.4:1 (110:77). Median follow-up for all patients was 14 years. One hundred fifteen patients had radiotherapy immediately after their first operation with a recurrence rate of 0.9% (1/115). Of the 115 there were 2 cases of radionecrosis (1 major, 1 minor), 1 case of permanent facial nerve palsy, 1 Frey Syndrome (post-gustatory sweating), and 1 salivary fistula. Seventy-two patients had radiotherapy delayed until one or more recurrences had been surgically treated. Nine (12.5%) of these developed yet further recurrence after radiotherapy. There were 2 cases of radionecrosis (1 major), 4 cases of facial nerve palsy (3 of which were complete), 16 cases (22.2%) of Frey Syndrome, and 1 case of malignant change in a parotid tumor. In addition one squamous cell carcinoma developed at the site of a needle implant 25 years later. Recurrences after radiotherapy continued beyond 20 years of follow-up. Patients having unsatisfactory surgery due to spill at operation or residual tumor left behind should have radiotherapy immediately and not delayed until local recurrence occurs because of the increased morbidity and the higher incidence of yet further recurrence.

Adenoma, Pleomorphic↗
PubMed1992

Gene-dosage mapping of 30 DNA markers on chromosome 21.

Using a slot-blot method for the dosage of single-copy sequences, the copy numbers of 30 chromosome 21 markers were assessed in the blood DNA of 11 patients with partial trisomy or monosomy 21 and in the DNA of a patient-derived human-hamster hybrid cell line carrying a microduplication of chromosome 21. The physical order of these markers on chromosome 21 was thereby determined.

Aneuploidy↗
PubMed1991

Biliary obstruction secondary to shrapnel.

Foreign bodies of the biliary tree represent infrequent causes of obstructive jaundice. We report a patient who developed biliary obstruction from metal shrapnel, 44 yr after a war injury. From our review of the literature, the syndrome of shrapnel-induced obstructive jaundice may occur many years after the initial injury. In the majority of patients, the missile lodges in the liver parenchyma, and migrates to the common bile duct. Complications from this injury include cholangitis, pancreatitis, and liver abscesses. As demonstrated by this case, computed tomography scan and endoscopic retrograde cholangio-pancreatogram may reliably detect this infrequent occurrence. With the development of therapeutic biliary procedures, many foreign bodies can be removed endoscopically. Thus, one should consider shrapnel-induced biliary obstruction in those patients with obstructive jaundice and prior combat injury.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1990

Angiotensin converting enzyme inhibitors. 10. Aryl sulfonamide substituted N-[1-carboxy-3-phenylpropyl]-L-alanyl-L-proline derivatives as novel antihypertensives.

Compounds 1a-g consisting of enalaprilat covalently bonded to aryl sulfonamides, including several known thiazide diuretics, were synthesized and tested for ACE inhibitory and diuretic and overall antihypertensive effects. All compounds were potent ACE inhibitors in vitro, with IC50 = 6.5-85 nM. At 10 mg/kg iv or ip in the rat, 1a-g inhibited the AI pressor response by 76-100%; inhibition declined significantly upon oral dosing. Compounds 1a and 1f at 100 mg/kg ip in the sodium-depleted, spontaneously hypertensive rats reduced blood pressure 28-35% and 41-42%, respectively. Compounds 1a and 1f elicited natriuresis and kaliuresis without accompanying volume increases in the rat; 1c at 25 mg/kg iv induced delayed diuresis. Compound 1f has been chosen for further development.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1990

The effect of chewing sorbitol-sweetened gum on salivary flow and cemental plaque pH in subjects with low salivary flow.

The purpose of this work was to study the effect of chewing a sorbitol-sweetened gum on whole and parotid salivary flow rates, and on the cemental plaque pH response to a sucrose rinse challenge, in subjects with low salivary flow. The results show that chewing a flavored sugarless gum significantly increases salivary flow rates in individuals with dry mouth. Additionally, chewing the sorbitol-sweetened gum effectively prevents the fall in cemental plaque pH generally seen in response to a sucrose challenge. This indicates that chewing a sorbitol-sweetened gum provides a palliative and possibly a protective benefit for people who suffer from dry mouth.

Chewing Gum↗
PubMed1989

Effect of sorbitol sweetened breath mints on salivary flow and plaque pH in xerostomic subjects.

The purpose of this study was to assess the effect of a sorbitol sweetened breath mint on salivary flow and plaque pH in subjects suffering from xerostomia. The breath mints effectively increased whole and parotid salivary flow rates during a 10-minute test period. Additionally, the mints reduced the acidogenic effect of a 10% sucrose rinse, as measured by changes in plaque pH. This change was presumably caused by the sialogogic action of the mints. The efficacy of sorbitol sweetened breath mints as a palliative, and possibly therapeutic aid for individuals with xerostomia compares favorably with the results of an earlier study similarly testing the effects of sorbitol sweetened chewing gum.

Dental Plaque↗
PubMed1988

Radionuclide ventriculography and two dimensional echocardiography as predictors of left ventricular performance during aortic vascular surgery.

Sixteen consecutive patients scheduled for elective aortic vascular surgery underwent preoperative LVEF determination employing two dimensional echocardiography (2DE) and radionuclide ventriculography (RNV). Measured and derived indices of cardiac function were recorded before and after induction of anaesthesia, aortic cross-clamping and aortic unclamping. Induction of anaesthesia was associated with significant decreases in mean arterial pressure (MAP), pulmonary capillary wedge pressure (PCWP), cardiac index (CI) and with a highly significant decrease in left ventricular stroke work index (LVSWI). Aortic cross-clamping was associated with significant increases in MAP and systemic vascular resistance (SVR) whereas aortic unclamping was associated with a significant decrease in SVR. Preoperative LVEF, as measured by RNV and 2DE, were similar. Resting ejection fractions correlated poorly with both preoperative cardiac indices and with changes in indices of left ventricular performance seen intraoperatively. Preoperative ejection fraction determination did not predict intraoperative left ventricular performance. Preoperative exercise scanning may prove more informative.

Aged↗
PubMed1987

Isolation and characterization of Pseudomonas putida R-prime plasmids.

A number of enhanced chromosome mobilizing (ECM) plasmids derived from the wide host range plasmid R68 have been used to construct R-prime plasmids carrying a maximum of two map minutes of the Pseudomonas putida PPN chromosome, using Pseudomonas aeruginosa PAO as the recipient. For one ECM plasmid, pMO61, the ability to form R-primes did not correlate with the ability to mobilize chromosomes in intrastrain crosses, suggesting that different mechanisms are involved. Physical analysis of one R-prime showed that 3.5 kb of chromosomal DNA had been inserted between the tandem IS21 sequences carried by the parent ECM plasmid.

Chromosome Mapping↗
PubMed1986

Physiologic effects of doxapram in idiopathic apnea of prematurity.

Twelve premature infants with significant apnea of prematurity while receiving therapeutic doses of aminophylline were given an intravenous infusion of doxapram, 2 or 2.5 mg/kg/hr. The ventilatory effects of the medication were monitored by means of face mask spirometry and airway occlusion studies. Doxapram therapy was associated with significant increases in minute ventilation, tidal volume, mean inspiratory flow, and airway pressure 100 msec after occlusion. Respiratory frequency and the relative duration of inspiration and expiration were unchanged. Paco2 decreased significantly during the infusion. The apnea attack rate, monitored by continuous recording, was significantly reduced after the first 6 hours of therapy. Six hours after starting doxapram, mean arterial blood pressure was significantly elevated, and continued to increase during the 24 hours of therapy. Doxapram is effective in treatment of apnea of prematurity refractory to aminophylline, and appears to act by increasing respiratory center output.

Aminophylline↗
PubMed1985

The natural history of subependymal germinal matrix hemorrhage.

A prospective study of 377 premature infants (less than or equal to 1500 gm) was undertaken to delineate the natural history of subependymal/intraventricular hemorrhage (S/IVH) and its complications using ultrasound (US) and computed tomography (CT). Low grade (I, II) S/IVH had a low mortality while higher grades (III, IV) still had elevated mortality rates. The addition of intraparenchymal hemorrhage (IPH) to S/IVH incrementally increased the incidence of death and other complications, suggesting IPH hemorrhage should be categorized separately. When a specific day could be identified, S/IVH had its onset in the first 7 days of life with peak incidence occurring on day 3. S/IVH appeared to be an event limited to less than 24 hours in all but 5% of infants in whom progression of hemorrhage was documented over a 24-hour period. The mortality rate of these progressive hemorrhages was high, 50%. The benign phenomenon of late S/IVH was detected in 5% of infants. These hemorrhages were clinically silent and of minor severity. Several complications of S/IVH were detected. Hydrocephalus was a significant complication only for higher grades of S/IVH. When present, severe hydrocephalus had an early onset and reached a maximum at around 3 weeks of age. "Atrophic change" of a cerebral hemisphere was detected in 30% of all S/IVH infants, while this was not seen in nonS/IVH infants. This "atrophic" abnormality had a marked predilection for the left hemisphere, independent of the site of the S/IVH. Periventricular leukomalacia (PVL) was documented by US in 2% of infants and could be detected in the first week of life. PVL presented in the first week of life as an echogenic lesion which developed "cystic" changes at approximately 3-4 weeks of age. This complication should be categorized separately from S/IVH.

Atrophy↗
PubMed1985

Treatment of urticaria pigmentosa with corticosteroids.

Based on a previous observation that the long-term application of potent topical corticosteroids under occlusion to normal skin resulted in the loss of mast cells, we investigated the effects of intralesional and topical steroids in urticaria pigmentosa (UP). Three patients with UP had lesions that were injected with triamcinolone acetonide. Four weeks after injection, all patients showed a loss of Darier's sign, and, by eight weeks after injection, there was a dramatic clearing of the plaques and a decrease in brown hyperpigmentation. By 12 weeks, mast cells were undetectable by light microscopy and transmission electron microscopy (TEM). The injection sites remained dramatically improved for as long as one year after treatment, and histamine content was reduced 95% in one patient 48 weeks after injection. In six patients, the topical application of 0.05% betamethasone dipropionate under occlusion to limited areas induced almost complete clearing of UP lesions. Lesions treated with an emollient under occlusion, as a control, demonstrated no change. After treatment, no mast cells were seen by light microscopy or TEM, and this persisted for at least 24 weeks. There was also a significant decrease in tissue histamine levels in the treated areas. The treated areas remained clinically improved for at least nine to 12 months. These data indicate that steroid therapy dramatically decreases the excess number of normal-appearing mast cells in UP as well as induces a prolonged resolution of UP lesions. Local corticosteroids thus are a useful therapeutic modality for UP.

Administration, Topical↗
PubMed1979

F cells in gynaecologic malignancy.

Red cells containing Hb F (F cells) were detected by immunofluorescence using a specific antiserum. In normal persons, the number of F cells was 2.5 +/- 1.1%. A significantly increased number of F cells was found in 65% of patients with cancer of the ovary, 69% of patients with cancer of the endometrium and in 22% of patients with cancer of the cervix. Highest values were obtained in cancer of the ovary and endometrium. There was no correlation between the number of F cells and stage of disease or degree of differentiation. It is postulated that in patients with malignant disease a humoral factor is produced which interferes with normal erythropoiesis resulting in a process of dedifferentiation.

Antibody Formation↗
PubMed1978

Quantitation of globin chains using cellulose acetate electrophoresis: analysis of fetal globin chain production.

A technique involving the quantitative estimation of globin chains using cellulose acetate electrophoresis is described, and applied to the analysis of fetal globin chain production. When cord blood was analyzed, there was poor correlation between the globin chain ratios namely beta/alpha, gamma/alpha and beta/gamma ratios with either age or weight of newborn babies between 36-40 weeks gestation: best correlations were obtained for the beta/gamma ratio against weight (P less than 0.05). However, there was highly significant correlation between the various globin chain ratios and either age or weight of the newborn infant up to 12 weeks of age (P less than 0.001). This technique allows visual demonstration and quantitation of abnormal haemoglobins in a single procedure.

Aging↗
PubMed1978

Coronary vasodilator activity of 13,14-dehydroprostacyclin methyl ester: comparison with prostacyclin and other prostanoids.

The effects of a recently synthesized, stable prostacyclin (PGI2) analog, 13,14-dehydro-PGI2 methyl ester, and authentic PGI2 and several other prostanoids on the coronary circulation were investigated in the intact dog by using a new technique to measure coronary sinus blood flow. The PGI2 analog, PGI2, and prostaglandin (PG) E2 and D2 each increased coronary sinus blood flow in a dose-related fashion when injected into the left coronary artery. The analog and PGE2 had similar vasodilator activity while PGI2 was slightly more potent. PGD2 was a moderately active coronary vasodilator whereas PGF2alpha was inactive. The coronary vasodilator effects of PGI2, its analog, PGE2, and PGD2 occurred at doses that had little effect on aortic pressure, left ventricular pressure and its first derivative, or on cardiac output and heart rate. The prostaglandin precursor arachidonic acid and the endoperoxide intermediate PGH2 both increased coronary sinus blood flow in a dose-dependent manner. The effects of arachidonic acid were inhibited by indomethacin. These data show that PGE2, PGI2, and a stable PGI2 analog are potent vasodilators in the canine coronary vascular bed and suggest that the vasodilator effects of arachidonic acid and PGH2 may be due to the formation of PGE2, PGD2, or PGI2 in the dog heart.

Animals↗
PubMed1978

Analysis of ultrasonographic criteria in the evaluation for ectopic pregnancy.

To assess the usefulness of ultrasound in diagnosing ectopic pregnancy, the ultrasonographic findings, pregnancy test results, and proven diagnoses in 148 patients referred for evaluation for ectopic pregnancy were reviewed. Of these patients, 33 were subsequently proven to have ectopic gestations. The ultrasonograms were coded for uterine size, intrauterine gestation sac, adnexal mass, adnexal ring, cul-de-sac fluid, or normal findings. With a positive pregnancy test, the presence of an intrauterine gestation sac excludes the diagnosis of ectopic pregnancy. Of those patients with positive pregnancy tests and no intrauterine gestation sac, 73% had ectopic pregnancy. All patients with normal ultrasonograms had other diagnoses. With a negative pregnancy test, the intrauterine findings are not helpful, and evaluation of the adnexa is more important. An adnexal ring is a significant, though not absolute, indicator of ectopic pregnancy. A normal scan excludes this diagnosis. Other criteria were not significant. A clinical approach to the evaluation for ectopic pregnancy, based on the data accumulated in this study, is suggested.

Female↗