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Biomedical subjects

K Nelson

Publications and source records attributed to K Nelson.

283 records · Page 16Linked to original sources
PubMedDate not supplied

Cathepsin B and glioma invasion.

Increased expression of cathepsin B has been reported in a number of human and animal tumors. This has also been observed in human gliomas where increases in cathepsin B mRNA, protein, activity and secretion parallel malignant progression. In the present study, we showed that cathepsin B was directly involved in glioma cell invasion. Activity of cathepsin B was an order of magnitude higher in glioma tissue than in matched normal brain. Inhibitors of cysteine proteases reduced invasion of glioma cells in two in vitro models: invasion through Matrigel and infiltration of a glioma spheroid into a normal brain aggregate. Glioma spheroids expressed higher levels of cathepsin B than did monolayers and the ability of subclones differing in cathepsin B activity to infiltrate normal brain aggregates paralleled their cathepsin B activity. We confirmed that intracellular staining for cathepsin B occurs at the cell periphery and in cell processes and observed extracellular staining on the cell surface. In addition, we demonstrated that intracellular cathepsin B located at the cell periphery and in processes was active. The cell surface cathepsin B colocalized with areas of degradation of an extracellular matrix component. We hypothesize that the increased expression of active cathepsin B in gliomas leads to increases in invasion in vitro and in vivo and have developed a xenotransplant model in which this hypothesis can be tested.

Animals↗
PubMedDate not supplied

Outcome of patients after air medical transport for management of nontraumatic acute intracranial bleeding.

INTRODUCTION: Patients with acute, intracranial bleeding (ICB), particularly from intracranial aneurysms, are believed to be at high risk for rebleeding or neurologic deterioration if subjected to noise, motion, or stress, but are transported by helicopter with increasing frequency. This study was undertaken to examine the characteristics, safety, and outcomes of air transport for patients with acute subarachnoid hemorrhage (SAH) or other forms of acute ICB in an air medical system. METHODS: Charts of all patients with spontaneous, acute ICB who were transported by air from 1986 through 1989 were reviewed. Age, gender, time of transport, transport management measures, pre- and post-transport Glasgow Coma Scale (GCS) score, intensive care unit (ICU) and hospital days, operations, and mortality were compiled for all patients and analyzed. RESULTS: Eighty-seven patients ranging in age from 2 to 83 years (mean: 47.5 +/- 18.5 years) met entry criteria. The source of bleeding was cerebral aneurysm in 37 patients; intraparenchymal hemorrhage in 29; an unidentified vascular source in 11; and arteriovenous malformation (AVM) in 10. Mean GCS score measured in 69 patients before and after transport was 10.5 +/- 4.5 Glasgow Coma Scale score did not change during transport in 61 patients (88%), improved in three (4%), and deteriorated in five (7%). Fifty-nine patients (69%) underwent operations, 36 (41%) within 24 hours of arrival. Mean ICU stay was 14 days (95% CI: 12-15); mean hospital stay was 36 days (95% CI: 27-45 days). Overall mortality was 25% (95% CI: 16-34 days). A GCS score of 3 to 8 at time of transport was associated with both increased hospital length of stay and higher mortality. Patients transported within eight hours of symptom onset had lower GCS scores, but outcome measures were not significantly different from those transported later. CONCLUSIONS: Emergency air medical transfer of patients with acute ICB for definitive neurosurgical care appears to be both safe and effective, and facilitates early definitive diagnosis and operative intervention.

Acute Disease↗
PubMedDate not supplied

Migraine patients show increased platelet vasopressin receptors.

This study was designed to investigate vasopressin receptor status (Bmax and Kd) on platelets, vasopressin plasma levels, and vasopressin-induced platelet aggregation in migraine patients (21 females and 6 males) during a headache-free interval and in a matched control group. In the migraine group, Bmax was significantly higher (P = 0.02) at 53.9 +/- 20.6 fmol/mg than in the control group (36.8 +/- 21.0 fmol/mg). A correlation between Bmax and high or low sensitivity to vasopressin as an aggregator was evident in the control group, but not in the migraine group. No differences in Kd or in plasma levels of vasopressin between the migraine and control group were apparent. Men in both groups were much less sensitive to vasopressin as a platelet aggregator than were women (P < 0.01). Whether the higher Bmax in the migraine group is a reflection of temporarily higher vasopressin levels during headache or reflects a primary increase in sensitivity to vasopressin, remains to be clarified. The higher sensitivity of platelets (as a model for vessel wall receptors) from women may indicate why many more women than men suffer from migraine. Since the Bmax of the vasopressin receptor on platelets from migraine patients is increased compared to controls, treating migraine headache with vasopressin may deserve more attention.

Blood Platelets↗
PubMedDate not supplied

Genetic regulation of murine hepatic arylsulfatase B activity during development.

The ratio of hepatic arylsulfatase B activity of C57BL/6J, SWR/J, and A/J mice is approximately 5:2.5:1. The activity variation between SWR/J and A/J mice can be attributed to the effects of Asr-1, a cis-acting regulatory element near or within As-1 (arylsulfatase B structural locus). However, C57BL/6J and SWR/J mice share similar Asr-1 alleles and have comparable arylsulfatase B activities in nonhepatic tissues. The high arylsulfatase B activity occurring in C57BL/6J compared to SWR/J liver is largely determined by a site near Asr-1 and As-1. The C57BL/6J allele promotes a more prominent spike of liver arylsulfatase B activity at 12 days postnatal age and maintains a higher activity in the adult compared to SWR/J mice. This liver-specific genetic element exerts a trans effect and acts by affecting the accumulation of arylsulfatase B molecules in liver tissue.

Animals↗
PubMedDate not supplied

Improved bioresorbable microporous intravascular stents for gene therapy.

Drug imbibing microporous stents are under development at a number of centers to enhance healing of the arterial wall after balloon coronary angioplasty procedures. The authors improved the mechanical strength and reservoir properties of a biodegradable microporous stent reported to this Society in 1994. A combined tubular/helical coil stent is readily fabricated by flotation/precipitation and casting/ winding techniques. A two stage solvent swelling technique allows precise adjustment of the surface hydrophilic/hydrophobic balance. These developments permit seven-fold improvement in drug capacity without significantly altering mechanical properties. Stents modified in this manner retain tensile and compressive strength and are suitable for remote deployment. Elution kinetics of these modified stents suggest they are suitable for gene delivery. Successful gene transfer and transmural expression have been demonstrated after implantation of stents impregnated with a recombinant adenovirus carrying a nuclear localizing beta-galactosidase reporter gene into rabbit carotid arteries. These studies suggest that surface modified, bioresorbable polymer stents ultimately may be useful adjunctive devices for gene transfer during percutaneous transluminal revascularization.

Angioplasty, Balloon↗
PubMedDate not supplied

Discrimination amongst Leishmania by polymerase chain reaction and hybridization with small subunit ribosomal DNA derived oligonucleotides.

A method for discriminating among Leishmania is described, based upon small subunit ribosomal DNA sequence differences. The method was to amplify the entire 2.2 kb small subunit rDNA by polymerase chain reaction using conserved primers specific for the 5' and 3' termini of the small subunit ribosomal RNA, and then hybridize the product dotted onto nylon membranes with labeled oligonucleotides. The design of the hybridization probes was based upon complete small subunit rDNA sequences from L. amazonensis, L. major and L. guyanensis and partial sequences of L. mexicana, L. braziliensis, L. tropica and L. chagasi. A high degree of sequence similarity (> 99%) among species was found. However, sufficient sequence divergence occurred to permit the design of internal oligonucleotide probes specific for species complexes. This procedure successfully discriminated amongst a wide range of Leishmania isolates. The method detected as few as 10 cultured organisms and detected parasites in tissue samples from experimentally infected animals. Non-radioactive labeling showed the same specificity and sensitivity as radioactive probes.

Animals↗
PubMedDate not supplied

The business of palliative medicine: management metrics for an acute-care inpatient unit.

For any palliative medicine inpatient unit to be economically viable, certain management metrics need to be followed. Palliative medicine can provide both a compassionate and economical service within the current acute inpatient hospital environment. In this article, we will review the administrative and financial factors we have identified that influence the business of acute palliative medicine.

Commerce↗
PubMedDate not supplied

Does vascular stapling improve compliance of vascular anastomoses?

Elastic properties of vessel walls are altered by vascular anastomoses. Such alterations may lead to neointimal hyperplasia, which is a common cause of reocclusion following vascular surgery. The severity of paraanastomotic hypercompliant zones and anastomotic compliance drop depend on suturing material and on elastic properties of the anastomotic vessel segments. This study compares paraanastomotic hypercompliance and anastomotic compliance drop when using a new vascular closure system (VCS) and a conventional, continuous suture line in the preparation of end-to-end anastomoses. Compliance of artery-artery, vein-artery, and polytetrafluoroethylene-artery anastomoses was measured in an artificial circulation system at mean pressures of 60, 90, and 120 mm Hg, comparing conventional suturing and the VCS. When using the VCS for vein-artery anastomoses, significantly less postanastomotic hypercompliance was achieved at mean pressures of 60 mm Hg (14.2 +/-3.8% above remote postanastomotic area), compared to suture (55.1 +/-14.8%, p<0.05). At 90 mm Hg, respective values were 11.0 +/-2.3% for VCS and 54.7 +/-10.1% for suture, p<0.01. At 120 mm Hg, in polytetrafluoroethylene-artery anastomoses, the anastomotic compliance drop was significantly less when using the continuous suture line (93.9 +/-1.1% below remote postanastomotic compliance), compared to VCS (97.2 +/-0.2%, p<0.05). Compared to conventional suturing, use of the VCS reduced postanastomotic hypercompliance in vein-artery anastomoses.

Anastomosis, Surgical↗
PubMedDate not supplied

Racial inequality and child neglect: findings in a metropolitan area.

Despite contradictory evidence, child neglect is often believed to occur more frequently in the African American than in the Caucasian population. This article reports findings on the racial differences among 182 families referred for neglect in a large metropolitan area. Although almost all of the families were poor, African American families in the neglect sample suffered even more from economic inequality than those in the general population. Implications of the findings for social welfare policy and child welfare practice are discussed.

Black or African American↗
PubMedDate not supplied

Comparative evaluation of cefadroxil and cephalexin in children and adolescents with pyodermas. Cefadroxil Once Daily Pyoderma Study Group.

This randomized, multicenter study compared the safety and efficacy of cefadroxil with that of cephalexin for the treatment of pyodermas in children and adolescents (1-18 years of age). Cefadroxil was given as a single oral daily dose of 30 mg/kg, and cephalexin 30 mg/kg/day was given in two divided doses. The maximum daily dose for both drugs was 1 gm, and treatment was administered for 10 days. Clinical and bacteriologic evaluations were made on days 4 or 5 during therapy and 2 to 4 days after therapy was completed. Of the 462 patients enrolled in the study, 156 patients in the cefadroxil group and 133 patients in the cephalexin group were evaluable. Staphylococcus aureus (56% of isolates) and Streptococcus pyogenes (39% of isolates) were isolated most frequently. The bacteriologic response was statistically greater in the patients treated with cefadroxil than in those treated with cephalexin (96% versus 89%; P = 0.042). A satisfactory clinical response was reported in 147 (94%) cefadroxil-treated patients and 122 (92%) cephalexin-treated patients (P = 0.476). The overall effective response to treatment was significantly higher with cefadroxil than with cephalexin (94% versus 86%; P = 0.024). Compliance with 9 or 10 days of therapy was similar in both treatment groups, although there was a difference between the two treatment groups with respect to completion of medication regimen: 95% of patients taking cefadroxil once daily--versus 65% of patients taking cephalexin twice daily--took 100% of their medication (P < 0.0001). Adverse events were infrequent and mild. The results of this study demonstrate that once-daily cefadroxil offers greater bacteriologic eradication and a better overall effective response than twice-daily cephalexin for the treatment of pyodermas caused by gram-positive pathogens in children and adolescents.

Adolescent↗
PubMedDate not supplied

Delivering HIV/AIDS services: the professional care provider speaks out.

BACKGROUND: This study evaluates the stresses and satisfactions experienced by health care and social service providers working in HIV/AIDS service agencies in New York City. This study was part of the Ryan White Title I Evaluation in New York City. METHODS: This study is based on semi-structured interviews with 86 randomly sampled providers from a representative sample of 29 HIV/AIDS service agencies. Personal interviews were completed with a cross section of AIDS care providers. All staff interviewed were audiotaped to facilitate data analysis. Staff discussed their frustrations and their personal satisfaction at working in AIDS care. In addition, all staff completed the Maslach Burnout Inventory (MBI) to facilitate a structured comparison of their levels of burnout. RESULTS: Using the three subscales of the MBI, we found that interviewed AIDS care providers experienced lower than expected levels of burnout. Compared to national norms, health care and social service providers showed above-average levels of personal accomplishment, below-average levels of depersonalization, and average levels of emotional exhaustion. Interview transcripts were analyzed focusing on three broad themes: unique stressors of HIV/AIDS services, positive aspects of HIV/AIDS services, and effective provider supports. The study confirms that HIV/AIDS care providers feel a high level of personal commitment to working with HIV-positive clients. Personal commitment to HIV-positive clients may blunt some of the stresses associated with HIV/AIDS care.

Acquired Immunodeficiency Syndrome↗