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Biomedical subjects

H Morris

Publications and source records attributed to H Morris.

At least 55 records · Page 3Linked to original sources
PubMed1998

Home care case management. Perspectives from the home front.

Focus groups were held with home care case managers in two cities in Canada which provided information on the role of the case manager, factors that influence decision making, recent changes that have taken place in case management, and the different and positive aspects of home care case management. Factors which influence decision making were grouped into organizational, client, family, other professionals, and case management factors. The differences in case managers' preparation and functions in the two sites are discussed. The difficult aspects of case management included making tough decisions related to client resources, and client, work life, and management issues. The positive aspects included the personal interaction with clients, the opportunity to follow through on services to clients, the diversity of case management work, and the opportunity for relatively independent professional practice.

Attitude of Health Personnel↗
PubMed1997

The role of the C-terminal domain of human collagenase-3 (MMP-13) in the activation of procollagenase-3, substrate specificity, and tissue inhibitor of metalloproteinase interaction.

Recombinant human procollagenase-3 and a C-terminal truncated form (Delta249-451 procollagenase-3) have been stably expressed in myeloma cells and purified. The truncated proenzyme could be processed by aminophenylmercuric acetate via a short-lived intermediate form (N-terminal Leu58) to the final active form (N-terminal Tyr85). The kinetics of activation were not affected by removal of the hemopexin-like C-terminal domain. The specific activities of both collagenase-3 and Delta249-451 collagenase-3 were found to be similar using two quenched fluorescent substrates, but Delta249-451 collagenase-3 failed to cleave native triple helical collagens (types I and II) into characteristic one- and three-quarter fragments. It was noted, however, that the beta1,2(I) chains of type I collagen were susceptible to Delta249-451 collagenase-3, which indicates that the catalytic domain displays telopeptidase activity, thereby generating alpha1,2(I) chains that are slightly shorter than those in native type I collagen. It can be concluded that the C-terminal domain is only essential for the triple helicase activity of collagenase-3. Binding of procollagenase-3 and active collagenase-3 to type I collagen is mediated by the C-terminal domain. Both collagenase-3 and Delta249-451 collagenase-3 hydrolyzed the large tenascin C isoform, fibronectin, recombinant fibronectin fragments, and type IV, IX, X, and XIV collagens; thus, these events were independent from C-terminal domain interactions. In contrast, the minor cartilage type XI collagen was resistant to cleavage. Kinetic analysis of the mechanism of inhibition of wild-type and Delta249-451 collagenase-3 by wild-type and mutant tissue inhibitors of metalloproteinase (TIMPs) revealed that the association rates for complex formation were influenced by both N- and C-terminal domain interactions. The C-terminal domain of wild-type collagenase-3 promoted increased association rates with the full-length inhibitors TIMP-1 and TIMP-3 and the hybrid N.TIMP-2/C.TIMP-1 by a factor of up to 33. In contrast, the association rates for complex formation with TIMP-2 and N.TIMP-1/C.TIMP-2 were only marginally affected by C-terminal domain interactions.

Amino Acid Sequence↗
PubMed1997

Analysis of the movement of line-like samples of variable length along the X-axis of a double TE104 and a single TE102 rectangular cavity

Movement of line-like samples with lengths from 5 to 50 mm along the x-axis of the double TE104 rectangular cavity has been analyzed. The observed dependencies of the EPR signal intensity versus sample position showed: (i) a sharp maximum for sample lengths from 5 to 20 mm; (ii) a plateau, over which the EPR signal intensity remained constant within experimental errors of 0.26-1.07%, for lengths from 30 to 40 mm; and (iii) a "sloping plateau," which could be approximated by the linear function (correlation, r = 0.98) for sample length 50 mm. Theoretical values of the experimentally observed dependencies of the intensity versus sample position were calculated using the modified sine-squared function and the correlation between observed and theoretically predicted dependencies is very good. The experimental dependence of the EPR signal intensity versus the sample length for samples situated at the same point in the cavity was nonlinear with a maximum for the 40-mm sample. The dependence of the EPR signal intensity upon the movement of a large cylindrical sample (o.d. 4 mm and length 100 mm) along the x-axis of the cavity was similar to that found for the 50-mm sample. However, an additional oscillating signal superimposed on the sloping plateau was observed. The presence of a large sample fixed in the complementary cavity of the double TE104 cavity caused an additional deformation of the signal intensity for a 30-mm sample which was moving in the first cavity. The primary effect was that the plateau was replaced by a region in which the intensity increased linearly with sample position, r = 0.99. Each of the above phenomena may be a source of significant errors in quantitative EPR spectroscopy. Cylindrical samples to be compared should be of identical length and internal diameter. Accurate and precise positioning of each sample in the microwave cavity is essential. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
PubMed1997

Arecoline via miniosmotic pump improves AF64A-impaired radial maze performance in rats: a possible model of Alzheimer's disease.

Male Sprague-Dawley rats, preoperatively trained in a 1-h delay non-match-to-position radial maze task, received bilateral stereotaxic injections of a selective cholinotoxin, ethylcholine aziridinium ion (AF64A: 3 nmol/3 microliters/lateral ventricle). Animals treated with AF64A made significantly more total postdelay errors than vehicle controls. Sustained delivery, via miniosmotic pumps, of arecoline (0.1, 0.3, 1, 3, 10, or 30 mg/kg/day sc for 14 days) attenuated the AF64A-induced cognitive impairment in a dose-dependent manner, producing an inverted U-shaped dose-response function which was optimal at 1.0 mg/kg/day. Following these studies, choline acetyltransferase activity was significantly reduced in hippocampi extracted from the AF64A-treated rats, indicating successful cholinotoxicity. This paradigm may be useful as a possible screen for potential Alzheimer's disease therapeutic agents. This conclusion is supported by published reports of beneficial arecoline effects observed following 2-week intravenous infusions in patients with Alzheimer's disease (Soncrant, Raffaele, Asthana, Berardi, Morris, & Haxby, 1993).

Alzheimer Disease↗
PubMed1997

1H NMR ganglioside ceramide resonance region on the differential diagnosis of low and high malignancy of brain gliomas.

1. The high-resolution 1H NMR (MRS) spectra of human brain tumor homogenates revealed a broad resonance at 5.3-5.4 ppm in glioblastoma multiforme (N = 16) and brain metastases (N = 3). The broad resonance was identified as ceramide, a sphingosine-fatty acid combination portion of ganglioside, indicating an elevated abundance of monounsaturated fatty acids. GLC analysis of gangliosides in the highly malignant glioblastoma multiforme revealed that the elevated monounsaturated fatty acid is oleic acid (C18:1). The resonance at 5.3-5.4 ppm region was not detectable in normal human brain (N = 2), in meningiomas (N = 2), or in low-grade astrocytomas (N = 12). In normal human brain the abundance of monounsaturated fatty acid is minimal. 2. This investigation was made possible because the method of producing homogenate resulted in (i) no loss of lipids during the process and (ii) a well-homogenised sample, with (iii) no loss in chemical integrity. 3. The properties of tumor gangliosides include antigenic specificity and immunosuppressive activity and the ceramide, a sphingosine-fatty acid combination, noticeably influences the ganglioside immunosuppressive activity. 4. The observation of 1H NMR ceramide resonance in high-malignant brain tumors emphasizes the dramatic role of aberant gangliosides and ceramide precursors on the grade of malignancy and invasiveness. 5. Further insight into the specific nature of the ceramide portion of gangliosides in grading the malignancy of brain tumors should be investigated further.

Astrocytoma↗
PubMed1997

The role of prostheses after resection of primary sarcomas of bone.

The advantages of the prosthetic replacement after resection of bone tumours include: 1) relatively simple technique, 2) modularity, 3) immediate function, 4) no disease transmission, 5) arthroplasty is possible. The disadvantages include: 1) late complications-asceptic loosening, bearing failure, fracture, 2) muscle re-attachment, 3) bone stock loss.

Age Factors↗
PubMed1997

Expression of glycans linked to natural killer cell inhibition on the human zona pellucida.

Protection of the gametes from potential immune responses is a primary function in human reproduction. The primary cell type responsible for the innate immune response in the uterus is the natural killer (NK) cell. NK cells normally recognize Class I major histocompatibility (MHC) molecules on potential target cells. Since both human spermatozoa and human oocytes do not express Class I MHC molecules on their surfaces, the appropriate cell surface signal that abrogates potential NK cell-mediated responses directed against these gametes is unknown. Recent evidence indicates that surface expression of bisecting-type N-linked glycans protects cells sensitive to NK cell-mediated lysis. We report that the zona pellucida of the human egg and plasma membranes of human spermatozoa potentially bind a lectin probe specific for bisecting type glycans in a carbohydrate-dependent manner. Since the innate immune response in the uterus is primarily mediated by NK cells, our results indicate that human gametes may be protected from this response by expressing bisecting type N-linked glycans on their surfaces.

Carbohydrate Conformation↗
PubMed1997

Muon spectroscopy applied to biological systems: a study of thiyl radicals, RS.

Thiyl radicals (RS.) are formed when positive muons (mu+) are implanted into solutions of thiocarbonyl compounds (C = S) in ethanol, tetrahydrofuran or formamide solvents. A solvent dependence is found, which reflects changing electronic interactions and overall conformations, suggesting that the properties of RS. radicals may be dependent on the polarity (philicity) of the environment in which they are formed.

Animals↗
PubMed1997

Assessment of left ventricular systolic function in low-echogenic patients by intravenous Infoson injection during dopamine echocardiography. An open, phase III trial.

This trial evaluated whether the intravenous injection of an ultrasound contrast agent (Infoson) facilitates the assessment of systolic function in 40 low-echogenic patients undergoing low-dose (4 mcg/kg/min) dopamine echocardiography. Interobserver difference in calculated ejection fraction at entry was > 10%. Echocardiographic monitoring was performed in the apical 4-chamber view at four intervals: baseline, no contrast; first Infoson injection; dopamine infusion, no contrast; dopamine infusion+second Infoson injection. The left ventricle was divided into 5 segments and analysis was performed by two blinded observers. Wall motion abnormalities, ejection fraction and the confidence in detecting the endocardial border, were assessed. Infoson provided adequate left ventricular opacification in 90% of the injections, with a significant improvement in endocardial border detection. The interobserver variability of ejection fraction measurements was significantly reduced. The probability of attaining concordance between the investigators on wall motion assessment improved significantly. These results suggest potential applications in stress echocardiography.

Aged↗
PubMed1996

Residual myocardial perfusion in reversibly damaged myocardium by dipyridamole contrast echocardiography.

In patients with previous myocardial infarction and left ventricular asynergy, dipyridamole infusion may have the capacity to unmask myocardial viability through transient recovery of contractile function in asynergic segments. The purpose of this study was to assess simultaneous changes in myocardial perfusion and LV function--elicited by dipyridamole infusion--in infarcted, asynergic segments. The echo contrast agent Albunex was injected into the left coronary artery of 19 patients (17 males, age 49-70 years) with previous myocardial infarction and baseline left ventricular asynergy, both before and after dipyridamole infusion (up to 0.56 mg.kg-1, i.v.). Analysis was not possible in three patients due to inadequate image quality and in two due to weak contrast. There were no major adverse events, or changes in vital signs or demonstrated on the electrocardiogram. After dipyridamole, 7/14 patients, showed an improvement in regional function of asynergic segments ('responders'), whereas seven patients did not ('non-responders'). Among non-responders, five had a myocardial perfusion deficit corresponding to 41% of the total left ventricular area before dipyridamole and to 38% after dipyridamole. No baseline perfusion deficits were observed in the remaining two non-responders; one of these, however, developed transient asynergy and perfusion deficit after dipyridamole. Among responders, five showed a normal perfusion pattern, both before and after dipyridamole, while the remaining two showed a perfusion deficit which markedly decreased after dipyridamole (from 32% to 13% of total left ventricular area). Thus, residual contractile reserve of asynergic, infarcted ventricular segments appears to be associated with myocardial perfusion either preserved at baseline or recruitable by a coronary dilator stimulus.

Aged↗
PubMed1995

First clinical experience with sonicated human serum albumin (Albunex) as an intrafallopian ultrasound contrast medium.

The safety and preliminary efficacy of a new ultrasound contrast medium. Albunex for evaluating Fallopian tube patency during transvaginal sonography were studied in seven women. All of the women had sought medical attention because of uterine fibroids and excessive menstrual bleeding and were scheduled for a subsequent hysterosalpingectomy 3 weeks after the ultrasound examination. Albunex was injected transcervically in doses ranging from 0.5 to 9 ml, alternating with saline, during concomitant transvaginal ultrasound scanning. There were no serious adverse reactions. Peroperative macroscopic and postoperative microscopic investigations of the endometrium. Fallopian tubes and peritoneal biopsies revealed no pathological changes. Agreement between hysterosalpingo contrast sonography (HyCoSy) and postoperative testing for the evaluation of tubal patency was observed in 12 out of 14 Fallopian tubes. These findings suggest that Albunex may safely be used as an intrafallopian contrast medium in ultrasound investigations.

Adult↗
PubMed1995

Surgical pathology of the lower uterine segment caesarean section scar: is the scar a source of clinical symptoms?

A series of 51 hysterectomy specimens was studied to define the pathological changes that are present in the area of the post-caesarean section scar. An attempt was made to correlate these findings with the clinical symptoms that had led to the hysterectomy. Scar tissue, present for 2-15 years since the last caesarean section, contributed to significant pathological changes, including distortion and widening of the lower uterine segment (75%), "overhang" of congested endometrium above the scar recess (61%), polyp formation conforming to the contours of the scar recess (16%), moderate to marked lymphocytic infiltration (65%), residual suture material with foreign body giant cell reaction (92%), capillary dilatation (65%), free red blood cells in the endometrial stroma of the scar (suggesting recent hemorrhage) (59%), fragmentation and breakdown of the endometrium of the scar (37%), and iatrogenic adenomyosis confined to the scar (28%). These findings suggest that in some patients the anatomical abnormalities that develop in relation to the scar (especially the presence of a prominent congested fold of endometrium or the presence of small polyps) could give rise to clinical symptoms such as menorrhagia. In addition, inflammatory infiltration with fibrosis and distortion of the lower uterine segment could contribute to such symptoms as lower abdominal pain, dyspareunia, and dysmenorrhea.

Adult↗
PubMed1994

In utero cleft palate repair in the ovine model.

Cleft lip and palate defects assume many forms from mild to severe, but all may be associated with abnormal craniofacial development. Even the most expert and sophisticated methods of surgical repair are followed by scar contraction and fibrosis, which result in skeletal defects, dental abnormalities, cosmetic disfigurement, and speech impairment. Recent clinical and experimental observations that fetal cutaneous wounds heal without scarring are of great potential interest in the management of cleft lip and palate. The objective of this study was to investigate the effect of prenatal repair of iatrogenically produced cleft palate on scar formation in the fetal lamb model. Ten ewes were operated on ranging in gestation from 70 to 133 days. Fifteen lambs were studied (nine cleft palates produced and repaired in utero; one cleft produced in utero and not repaired, four normal, unoperated palates; and one cleft palate produced and repaired 1 week postnatally). The lambs were delivered normally at 145 to 147 days gestation and maintained with the ewe until 1 month of age. The lambs were euthanized, and the surgical area of the palates studied grossly and histologically. Animals operated at 112 days or later in gestation exhibited scars both clinically and histologically. The animals that had cleft palate produced and repaired at 70 days gestation did not have a visible palatal scar at 1 month of age. Histologically, there was evidence of minimal scarring without disruption of normal architecture. Studies are underway to determine the impact of reduced scarring on craniofacial growth after palatal repair during mid gestation in the ovine model.

Animals↗