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Biomedical subjects

J Carter

Publications and source records attributed to J Carter.

At least 199 records · Page 11Linked to original sources
PubMed1989

Purification and properties of a protease from developing porcine dental enamel.

A protease of molecular weight 29,000 was isolated and purified using ammonium sulphate precipitation, lentil lectin-Sepharose affinity chromatography and DEAE-5PW ion-exchange chromatography. The protease had an unusual amino acid composition including 5% serine, 6% proline and 20% tyrosine. It was a glycoprotein containing 12-15% carbohydrate by weight. Activity was optimal at 40-45 degrees C using [3H]-acetyl casein substrate and at 40-55 degrees C using [3H]-acetyl enamel protein substrate. It was irreversibly denatured at 80 degrees C and above. With [3H]-acetyl casein the pH optimum was 8.0-8.5 and with [3H]-acetyl enamel protein it was 6.0-8.0. There was no activity below pH 5.0, and irreversible denaturation occurred at pH 4.0 and below. No autodegradation occurred with storage at 4 degrees C for 30 days at pH 7.0. Phenylmethylsulphonyl fluoride, mercuric chloride, and p-aminobenzoic acid completely inactivated the protease. The enzyme had no requirement for calcium. The sites of cleavage of the oxidized B-chain of insulin were the Cys-Gly and Arg-Gly bonds. The enzyme was therefore an endopeptidase. Cleavage of Na-benzoyl-L-arginine ethyl ester, but not Na-benzoyl-L-tyrosine ethyl ester, suggests that the protease is of the trypsin family. On the basis of its physical and enzymic properties the protease is a serine proteinase and, consistent with existing terminology, has been named proteinase pemB.

Amino Acid Sequence↗
PubMed1989

Immunoglobulin-secreting cells in close proximity to the mid-gestation mouse embryo.

A reverse haemolytic plaque assay has been used to detect cells secreting IgM and IgG from areas in close proximity to mid-gestation mouse embryos. These cells were obtained from the fetal-placental unit and from the decidual mass of mice on the 9th or 10th day of syngeneic pregnancy. Cryohistology using affinity prepared goat antibodies specific for mouse Ig isotypes, coupled to horseradish peroxidase by a second antibody, showed that free Ig and cells containing Ig, are located closely but externally to the extra-embryonic membranes and also in areas close to the developing placenta in the decidua basalis. We suggest that some of the identified Ig-forming cells may be producing antibodies specific for antigens on the extra-embryonic membranes and may thus be acting as blocking (enhancing) antibodies.

Animals↗
PubMed1989

Tongue flap repair of oro-nasal fistulae in cleft palate patients. A review of 20 patients.

At University College Hospital, between 1980 and 1985, sixty patients with cleft lip and palate deformity underwent transpalatal maxillary advancement for the correction of mid-face hypoplasia. One third of these patients subsequently required closure of oro-nasal fistulae and we present the results of these twenty cases where anteriorly based dorsal tongue flaps were used. Seventeen were successful and the causes of three failures are discussed.

Adolescent↗
PubMed1989

The measurement of villus cell population size in the mouse small intestine in normal and abnormal states: a comparison of absolute measurements with morphometric estimators in sectioned immersion-fixed material.

From a functional viewpoint, the most important part of the small intestinal mucosa is the villus epithelium; in the experimental study of intestinal adaptation it is often necessary to estimate the size of the population. For these reasons, a systematic study of methods of measuring the size of the villus cell population was undertaken in villi of normal morphology from control animals, and in villi of abnormal morphology as produced by treatment of mice with cytosine arabinoside (Ara-C). The villus cell population can be measured with precision and accuracy in both normal and abnormal mucosal states, with a relative standard error usually less than 5%, with good reproducibility, and with very low counting errors. In the mouse a practically linear relationship between the villus cell population size and position in the small intestine can be shown. In normal, control animals, linear estimates of villus population, for example the villus height, the villus core height, and the villus row count measured in sections of immersion-fixed material, were found to be rough approximations as indicators of the villus cell population, and were highly correlated with it. Product variables, comprising the products of a height with a width measurement, show a large improvement over the linear variables as estimators of villus cell population. In populations of abnormally shaped villi produced by Ara-C, both linear and product variables showed a considerable decrease in correlation with the villus cell population. Consequently, indirect, linear measurements of the villus population size do not accurately reflect the size of the villus population in abnormal villi. Finally, a method comparing theoretical and measured surface: volume indices was used to indicate that the most appropriate shape for normal mouse villi is a simple cylinder; this method would also be applicable for other villus cell populations.

Animals↗
PubMed1989

A comparative study of proliferating (borderline) and invasive epithelial ovarian tumours in young women.

A series of 18 patients with proliferating or borderline ovarian tumours and 18 with invasive ovarian tumours is discussed. Proliferating tumours occurred at a younger mean age than invasive disease, and presented at an earlier stage, both contributing factors to their more favourable outlook. Histopathological assessment revealed that the majority of both proliferating and invasive tumours were of serous origin. Mucinous cell type occurred less often as did the endometrioid and clear cell types. The management of the proliferating tumours involved 'radical' surgical procedures in 11 of 18 (61.6%) patients. Only 7 patients (38.8%) had conservative surgical procedures performed. Six patients (33%) had adjuvant chemotherapy while 2 (11%) also underwent abdominopelvic irradiation. All patients with invasive disease had radical surgery and adjuvant chemotherapy and 2 also received abdominopelvic irradiation. The fact that epithelial malignancies of the ovary do occur in younger women needs to be remembered by gynaecologists contemplating surgical procedures on younger patients with adnexal masses. Proliferating or borderline tumours tend to occur more frequently in the younger age groups, and contrary to the implication of their name, they are associated with significant morbidity and mortality.

Adolescent↗
PubMed1989

Serum uric acid levels in normal pregnancy.

Sixty-four patients were assessed throughout pregnancy to determine normal serum uric acid levels (mean +/- 2SD). Serum uric acid levels increased significantly from early pregnancy levels of 0.13-0.33 nmol/L to levels of 0.18-0.45 mmol/L at full-term (p less than 0.005). Factors implicated in uric acid homeostasis contributing to these changes are discussed.

Adolescent↗
PubMed1989

Survey on prerefferal practices: responses from State deparetments of education.

A six-item survey was sent to state directors of special education (or their equivalent) in all 50 states and the District of Columbia. Items were developed to assess the type and level of prereferral intervention usage reported by state level special education administrators. Despite a lack of empirical support and a relatively inconclusive success rate, many state level administrators reported that they require or recommended the use of prereferral intervention strategies.

Administrative Personnel↗
PubMed1989

Gadolinium-DTPA-enhanced MR imaging of the postoperative lumbar spine: time course and mechanism of enhancement.

To define the time course and mechanism of enhancement of epidural fibrosis after gadolinium-DTPA (Gd-DTPA) injection, we undertook a three-part study in humans and dogs with epidural scar after spine surgery. First, the dynamic in vivo contrast-enhancing properties of epidural scar were assessed by using sequential fast (18-sec) spin-echo sequences after contrast injection. Epidural scar in dogs rapidly enhanced; peak enhancement (101%) was 6 min after injection, with a slower decline toward baseline to 45% after 44 min. Epidural fibrosis in patients followed a similar pattern, with a maximum enhancement of 73% after 5 min. Paraspinal muscle had a lower peak enhancement in both patients (36%) and dogs (22%). Second, vascular injection in two dogs with India ink demonstrated multiple small vessels throughout the epidural scar. Third, light and electron microscopy was performed on epidural scar obtained at reoperation in both patients and dogs. Light microscopy showed multiple small capillaries scattered throughout a background of collagen. Electron microscopy demonstrated a wide variation in the junctions between endothelial cells ranging from "tight" to "loose." Regions of endothelial discontinuity were also visualized. This study suggests that Gd-DTPA diffuses rapidly into the extravascular space in epidural scar, with a slower, net movement toward the intravascular compartment as the agent is renally filtered. The contrast agent transgresses the endothelium through "leaky" intercellular junctions and areas of endothelial discontinuity.

Animals↗
PubMed1988

Improved treatment results for lymphoblastic lymphoma in adolescents and adults using a doxorubicin-based (APO) protocol.

A multi-drug chemotherapy (APO) protocol incorporating doxorubicin was used to treat 12 patients (median age 19 years) with lymphoblastic lymphoma. The APO protocol consisted of intensive induction and consolidation phases, prophylactic CNS treatment, and 24 months of maintenance therapy. Eleven patients had an anterior mediastinal mass, while T cell markers were found on the lymphoma cells in eight of the nine cases tested. Two patients had initial CNS involvement, with one also having bone marrow replacement. Complete remission was obtained in all patients, with no deaths due to treatment toxicity. There have been four relapses, one in the patient with initial CNS and leukemic disease, two in abdominal sites, and in the mediastinum in one patient. With a median follow-up time of 30 months from diagnosis, 67% of patients remain alive in first remission. These results indicate that the APO protocol provides a highly effective approach to the management of this high grade lymphoma in adolescents and adults.

Adolescent↗
PubMed1988

Distribution of the glucose-1,6-bisphosphate system in brain and retina.

The distribution of glucose-1,6-bisphosphate (G16P2) synthase was measured in more than 70 regions of mouse brain, and nine layers of monkey retina. Activities in gray areas varied as much as 10-fold, in a hierarchical manner, from highest in telencephalon, especially the limbic system, to lowest in cerebellum, medulla, and spinal cord. The synthase levels were significantly correlated among different regions with G16P2 itself, as well as with previously published levels of a brain specific IMP-dependent G16P2 phosphatase. In contrast, neither G16P2 nor either its synthase or phosphatase correlated positively with phosphoglucomutase, and in all regions the G16P2 levels greatly exceeded requirements for activation of this mutase. This strengthens the view that G16P2 has some function besides serving as coenzyme for phosphoglucomutase. However, attempts to correlate the "G16P2 system," as defined by the three coordinately related elements, synthase, phosphatase, and G16P2, with other enzymes of carbohydrate metabolism, or with regional data of Sokoloff et al. [J. Neurochem. 28, 897-916 (1977)] for glucose consumption, were unsuccessful. This leaves open the possibility that brain G16P2 might serve as a phosphate donor for specific nonmetabolic effector proteins.

Animals↗
PubMed1988

Pseudotumor cerebri, a rare adverse reaction to tetracycline therapy. A case report.

WITH THE MORE FREQUENT USE of antibiotics as adjuncts to periodontal therapy today, it is imperative that dental clinicians be aware of adverse reactions to these drugs, regardless of their reported incidence. It is the purpose of this case report to present and describe a rare adverse reaction to tetracycline hydrochloride called pseudotumor cerebri or benign intracranial hypertension. It is manifested by an abnormal increase in intracranial pressure and papilledema in a patient with an otherwise normal neuroradiologic condition. Although severe headache appears to be the most bothersome acute symptom, the more important long-term side effect is visual loss caused by the papilledema. Treatment should be directed towards discontinuation of the drug therapy, and immediate referral to a physician for a neuro-ophthalmic evaluation.

Actinobacillus Infections↗
PubMed1988

Garlic revisited: therapeutic for the major diseases of our times?

Garlic may play an invaluable role in the prevention and therapy of the major causes of death. Anecdotal, basic, and clinical research data are confirming the efficacy of this herb in the treatment of hyperlipemia, cancer, heavy-metal intoxication, infectious diseases, hypertension, free-radical damage, and immune deficiency states. Garlic's broad antimicrobial spectra and its ability to modulate immunity may play a strategic role in the acquired immunodeficiency syndrome pandemic. A review of the literature supports a greater scrutiny of this herb's therapeutic potential.

Garlic↗
PubMed1987

Cystoid macular edema following corneal-relaxing incisions.

We believe that this is the first report of cystoid macular edema following corneal-relaxing incisions. Both cases we describe occurred in pseudophakic eyes, one of which contained an ultraviolet light-absorbing intraocular lens. One case was complicated by a corneal perforation and postoperative inflammation. The other case had no apparent intraoperative or postoperative complications other than the cystoid macular edema. In both cases, the cystoid macular edema resolved after the institution of medical treatment, and visual acuity returned to preoperative levels.

Aged↗