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Biomedical subjects

J Cummings

Publications and source records attributed to J Cummings.

175 records · Page 10Linked to original sources
PubMedDate not supplied

Adriamycin-loaded albumin microspheres: preparation, in vivo distribution and release in the rat.

Adriamycin-loaded bovine albumin microspheres have been prepared by a technique that allows preparation and administration to animals on the same day. Criteria adopted for injection were that microspheres should be stable and of a size such as to become trapped in capillary beds. These conditions were fulfilled by preparing microspheres using glutaraldehyde concentrations greater than 0.5 per cent and the appropriate combination of stirring speed and continuous phase viscosity. After systemic administration rats were sacrificed at intervals and major visceral organs examined for entrapped microspheres and serum for released drug. Microspheres sieved out in the first capillary bed encountered, the lung, then following biodegradation they disappeared at a rate dependent on the amount of cross-linking agent used in their preparation. In contrast to bolus injection, serum drug levels after microsphere administration indicated an initial rapid release followed by a more protracted phase lasting at least 24 h. This latter observation is consistent with drug release during biodegradation of carrier.

Animals↗
PubMedDate not supplied

Case report: total parenteral nutrition extravasation associated with spinal cord compression and necrosis.

A preterm infant, whose course was complicated by sepsis, necrotizing enterocolitis with jejunal perforation, intraventricular hemorrhage and cerebellar hemorrhage, suffered permanent and total paralysis below the neck from extravasation of parenteral nutrition fluids through a femoral venous catheter. MRI imaging revealed extravasation of fluid into the paraspinus musculature with extension into the spinal canal. This fluid was identified as hyperalimentation and intralipid. Postmortem examination found evidence of necrosis of the spinal cord as well as perforation of the right iliac vein.

Catheterization, Central Venous↗
PubMedDate not supplied

Neospora caninum infection in English Springer Spaniel littermates. Diagnostic evaluation and organism isolation.

Progressive paraparesis developed in four male English Springer Spaniel pups from a litter of five during the first 10 weeks of life. Two of the pups, which had the earliest onset of neurologic signs, were euthanatized without further workup. However, a detailed investigation was completed on the remaining two littermates at 12 weeks of age. Both pups had progressive paraparesis for 3 to 4 weeks before presentation, with one dog developing subsequent asymmetric pelvic limb extensor rigidity. Based on results from neurologic examination, cerebrospinal fluid (CSF) analysis, electrophysiology, and muscle/nerve biopsy, a presumptive diagnosis of protozoal polyradiculitis and polymyositis was made. Necropsy of the most severely affected pup confirmed the clinical diagnosis of inflammatory nerve root and muscle disease but no organisms were found. To increase the potential yield of organisms, the second pup was placed on immunosuppressive doses of corticosteroids and euthanatized 2 weeks later. Numerous organisms were found in lesions in muscle and the central nervous system. Organisms grew in tissue culture and were isolated from the peritoneal fluid of gerbils inoculated with infected tissue. Organisms were not isolated from inoculated mice, guinea pigs, rabbits, and hamsters. No parasites were seen in feces or tissues of three cats fed infected dog tissues. Serologic testing demonstrated a strong positive titer to Neospora caninum in both pups, and electron microscopy showed the characteristic morphology of this parasite.

Animals↗
PubMedDate not supplied

COAD (clinical outcome assessment documentation) charting: using the quality improvement process to meet the new JCAHO nursing standards.

The shortage of nurses has prompted departments across the nation to examine nursing practices in individual healthcare facilities and to initiate changes where relevant. Saint Thomas Hospital, a 571-bed tertiary-care facility, developed a number of strategies designed to allow nurses to focus on skills consistent with professional practice and to reassign technical and clerical duties to other members of the healthcare team. One of the changes implemented was the clinical outcome assessment documentation (COAD) system, which communicates the plan of care without the use of a separate form, expedites charting times, and eliminates duplication. This system also facilitates the documentation of the patient's progress toward outcome-oriented goals. Evaluation of the COAD system after implementation showed improvement in documentation of the nursing process, staff satisfaction with the system, and compliance with the Joint Commission's 1991 nursing standards.

Hospital Bed Capacity, 500 and over↗
PubMedDate not supplied

Exclusion mapping in familial non-specific dementia.

We present genetic linkage data in a large family in which non-specific dementia is inherited as an autosomal dominant trait. We have analyzed 45 highly polymorphic microsatellite sequences and excluded a quarter of the genome as the site of the pathogenic mutation in this family.

Adult↗
PubMedDate not supplied

Tea drinking and haemostasis: a randomized, placebo-controlled, crossover study in free-living subjects.

The hypothesis that tea drinking may protect against coronary heart disease (CHD) through effects on clotting as measured by plasma fibrinogen, tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) was tested in 65 healthy volunteers (31 men and 34 women; aged 20-74 years) in a randomized, blind, placebo-controlled, crossover study lasting 10 weeks (run-in phase 2 weeks, tea and placebo phases 4 weeks). During the placebo phase, intakes of milk, sugar, water and caffeine were matched to those in the tea phase during which 6 mugs of tea were drunk daily. Compliance with tea intake was measured by marking tea bags with p-aminobenzoic acid and measuring recovery in 24-hour urine collections. The mean +/- SD fibrinogen level, PAI-1 activity and tPA antigen level at baseline of 2.91 +/- 0.81 g/l, 7.9 +/- 5.3 U/ml and 4.76 +/- 2.17 ng/ml, respectively, were in the normal range. No significant differences in these variables between the run-in, tea or placebo phases were observed. The putative protective effect of tea against development of CHD is not mediated through effects of black tea on fibrinogen, tPA or PAI-1.

Adult↗
PubMedDate not supplied

Posterior subluxations of the medial and lateral tibiofemoral compartments. An in vitro ligament sectioning study in cadaveric knees.

We report for the first time the abnormal increases in posterior subluxation of the medial and lateral tibial plateaus after sectioning the posterolateral structures and posterior cruciate ligament. We applied specific forces and moments to the knees of seven cadaveric whole lower limbs and measured the position of the tibia at which the ligaments and the geometry of the joint limited motion. Removal of only the posterolateral structures resulted in an average increase in posterior translation of the lateral tibial plateau of 8.0 mm (range, 5.7 to 10.6) at 30 degrees of flexion over the intact state (P < 0.01), but no significant increase at 90 degrees of flexion (mean, 2.7 mm). Knees with underlying physiologic cruciate ligament laxity (high anterior/posterior displacement in the intact knee) had the greatest lateral tibial plateau subluxation (P < 0.01). There was no abnormal posterior translation of the medial tibial plateau. After sectioning the posterior cruciate ligament and the posterolateral structures, statistically significant increases in posterior translation of both the medial and lateral tibial plateaus occurred at 30 degrees and 90 degrees of flexion (P < 0.01). The increase in posterior translation of the lateral tibial plateau over the intact state averaged 17.8 and 23.5 mm at 30 degrees and 90 degrees of flexion, respectively; for the medial tibial plateau this increase averaged 7.6 and 12.3 mm at 30 degrees and 90 degrees of flexion, respectively. The diagnosis of abnormal tibiofemoral rotatory subluxations requires knowledge of the anteroposterior direction and magnitude of each tibial plateau under both low flexion and high flexion knee angle positions.

Adult↗
PubMedDate not supplied

In vitro release of adriamycin from drug-loaded albumin and haemoglobin microspheres.

Release of adriamycin from albumin and haemoglobin microspheres has been determined in vitro using a flow through system. Release from cross-linked albumin microspheres is controlled by the percentage of glutaraldehyde used but release profiles of spheres of 23, 41 and 60 microns diameter were virtually superimposable. Not all of the adriamycin is released from the microspheres over 20 h; as biodegradation occurs in vivo after 24 h the amount of drug remaining in the system at 20 h is likely to be principally released by degradation of the protein matrix in vivo. Estimates of the retained adriamycin vary from 16-26 per cent for albumin (n = 3) and 30 per cent for haemoglobin (n = 1).

Albumins↗
PubMedDate not supplied

Adriamycin-loaded niosomes: drug entrapment, stability and release.

The effect of encapsulation of adriamycin into niosomes, and its resultant chemical purity, was studied by means of HPLC and high-speed scanning spectrophotometry (the simultaneous use of which allowed investigation of potential non-fluorescent drug degradation products), and the process shown not to adversely affect the drug. Efficiency of entrapment of aqueous solutions of the drug was apparently dependent on neither vesicle composition nor method of production, and evidence of a degree of surfactant-adriamycin association was provided by the high entrapment values. Light-induced drug degradation was reduced by niosome encapsulation, and efflux of entrapped adriamycin was decreased by inclusion of cholesterol into the vesicles, in a manner similar to that reported for liposome preparations. Thus only chemically pure adriamycin was entrapped in, and released from, niosomes.

Doxorubicin↗
PubMedDate not supplied

In vitro formation of a toxic aglycone metabolite of 4-demethoxydaunorubicin in conditions that parallel the stomach.

4-Demethoxydaunorubicin is a new anthracycline anticancer drug administered orally to cancer patients. In vitro chemical stability has been studied in conditions that parallel the stomach (pH 1, dark, 37 degrees C) by HPLC. The drug was converted to its aglycone form at a rate of 3% (total starting amount) per hour. Thus, after only 3 to 4 hours significant aglycone formation had occurred (greater than 10%). The aglycone was detected to be present in patient urine in significant amount. Anthracycline aglycones lack cytotoxicity but retain toxic potential to host tissues. Formation in vivo in the stomach would result in a reduction in the therapeutic index of the drug.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Usefulness of magnetic resonance imaging for the diagnosis of acute musculoskeletal infections in children.

A 30-month prospective study was conducted on 43 children who presented with clinical findings suggestive of acute hematogenous musculoskeletal infection. Magnetic resonance imaging (MRI) was found to be extremely sensitive (0.97) and specific (0.92) in helping to diagnose these infections, with only one false positive and one false negative study. Bone scans are more likely to yield false positive and negative examinations. MRI is particularly useful in difficult cases in which there are conflicting clinical data or infection involving the spine or pelvis. After MRI demonstrates the location of the disease process, histologic and/or bacteriologic confirmation of the etiology is still mandatory.

Acute Disease↗