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Biomedical subjects

M York

Publications and source records attributed to M York.

33 records · Page 2Linked to original sources
PubMed1993

The distribution of medication along the spinal canal after chronic intrathecal administration.

Chronic intrathecal drug infusion for the treatment of neurological diseases, such as spasticity and chronic pain, has become an accepted method of therapy in recent years. Concurrent pharmacokinetic studies have shown that the cisternal cerebrospinal fluid (CSF) drug level is considerably lower than the lumbar CSF level during continuous infusion into the lumbar subarachnoid space. One factor that makes analysis of this decline in drug level difficult to quantify is that it is only feasible to sample CSF at the two extremes of the spinal subarachnoid space. Using a radionuclide technique, we have examined the distribution along the spinal canal of a hydrophilic compound, indium-111 diethylenetriamine pentaacetic acid, that was delivered over 72 hours into the lumbar subarachnoid space in five patients with implanted drug pumps. Over a 20-cm distance of the thoracic cord, radionuclide counts decreased gradually so that the indium-111 diethylenetriamine pentaacetic acid concentration surrounding the cord at the T2 vertebral level was 43% of that at the T12 level in four patients. Therefore, it appears that even with a hydrophilic compound, which minimizes spinal cord capillary losses, there is still a considerable reduction of CSF drug concentration along the spinal canal. The clinical implication of this gradual decline in drug level is that for intrathecal infusion of relatively hydrophilic compounds there may not be any advantage in placing the catheter tip at more rostral locations, such as at the midthoracic or cervical cord.

Analgesia, Epidural↗
PubMed1992

In vivo genotoxicity studies with p-benzoquinone dioxime.

P-Benzoquinone dioxime (BQD) appears to be a sex-specific rat carcinogen inducing tumours of the urinary bladder in female rats. The present paper shows that BQD is a direct-acting mutagen in Salmonella typhimurium TA98, confirming published data. In contrast to this in vitro data, negative results were obtained after oral administration of BQD to female rats in both the bone marrow micronucleus test and the in vivo liver UDS test. BQD did, however, induce a marked effect upon S-phase synthesis in the livers of female rats between 14 and 48 hr after a single oral dose of 250 mg/kg. A similar effect was also observed in the livers of male rats. There was no evidence of hepatotoxicity (in terms of elevated liver enzyme levels) after treatment of female rats with the compound indicating that the increase in cell proliferation was due to a direct mitogenic effect of BQD in this organ. Some liver mitogens have been found to be liver carcinogens; this does not appear to be the case for BQD. Nevertheless, the mitogenic activity of this compound might play a contributory role to the induction of bladder cancer in rats if it also acted as a mitogen in this tissue. Further studies are indicated, measuring genotoxicity and cell-proliferative activity in the bladder in order to further elucidate the mechanism of action of this compound as a rodent carcinogen.

Administration, Oral↗
PubMed1990

Blood culture phlebotomy: switching needles does not prevent contamination.

OBJECTIVE: To determine how switching to a sterile needle after phlebotomy and before the inoculation of blood culture bottles affects the rate of skin flora contamination. DESIGN: A randomized trial. SETTING: Medical inpatient services and the emergency department of a large university hospital. PARTICIPANTS: Housestaff, medical students, nurses, and physician assistants who draw blood cultures on the general medicine, cardiology, and renal transplant units and in the emergency department. INTERVENTIONS: Phlebotomists were randomly assigned to draw blood cultures by either the conventional method or an alternative method in which the blood culture bottles were inoculated without switching needles. MEASUREMENTS AND MAIN RESULTS: There was no difference in the rate of contamination between the conventional technique (6 of 462 cases, 1.30%) and the alternative technique (7 of 451 cases, 1.55%) (95% CI for the difference in rates, -1.8% to 1.2%). CONCLUSIONS: The needle switch in the conventional blood culture technique does not reduce the rate of skin flora contamination. Blood cultures should no longer be obtained by switching needles.

Blood Specimen Collection↗
PubMed1989

Unexpected isolation of Bordetella pertussis from patients with acquired immunodeficiency syndrome.

We isolated Bordetella pertussis from three patients with acquired immunodeficiency syndrome who underwent diagnostic bronchoscopy for evaluation of respiratory symptoms. The B. pertussis isolates were recovered from medium (charcoal-yeast extract agar) formulated to enhance recovery of Legionella spp., and one of the isolates stained positively with antisera directed against Legionella spp.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[Endoscopic autotransplantation of fat tissue in the treatment of urinary incontinence in the female].

Urinary incontinence in women is a frequently encountered condition. We present an endoscopic technique for correction of this disorder, which may be used to treat vesico-ureteral reflux and also post-prostatectomy incontinence in men. The procedure, carried out under epidural anesthesia, consists of implanting cylinders of fatty tissue removed by liposuction from subcutaneous tissue, in the bladder neck using an endoscopic injection needle. Our series presently includes 12 patients suffering from incontinence without cystocele, followed up on average for 6 months. Although it is too early to make conclusions, the results are quite promising in terms of subsequent prognosis.

Adipose Tissue↗
PubMed1985

Successful chemotherapy for cystosarcoma phyllodes in a young woman.

Cystosarcoma phyllodes is a rare neoplasm of the breast. The tumor contains both stromal and epithelial elements. Local excision or simple mastectomy is usually curative. Most recurrences are local and can be controlled with excision. We treated a 23-year-old woman in whom disease had metastasized to the lungs with six courses of doxorubicin hydrochloride and cisplatin at three-week intervals and achieved complete remission.

Adult↗
PubMedDate not supplied

A critical review of the assessment of eye irritation potential using the Draize rabbit eye test.

Traditionally, the eye irritation potential of substances and products has been assessed using the Draize eye test. While this procedure has been criticized in terms of its scientific validity and its ethical acceptability, it remains the only official, government-recognized procedure for predicting the irritant effect of substances in the eye. The relative absence of serious human accidents testifies to the success of the predictions. With the development of alternative non-animal procedures to replace the Draize test, the data generated in the Draize procedure are also being used as a 'gold standard' against which the performance of alternative procedures is measured. The major sources of variability are small group size and inability of existing scoring systems to reflect the complexities of the total in vivo response. In addition, the use of algorithms to simplify the in vivo data (for comparison with in vitro data) also misrepresents the in vivo data. Addressing the above issues would inevitably increase the use of animals. This would go against the general public demand for a reduction in the use of animals. Therefore the issue is to decide upon a simple parameter (for comparison with in vitro data) that encompasses the complexity of the irritation response and accurately reflects irritation without requiring the use of additional test animals. Such a parameter could be the recovery time. In addition, controlled human testing to benchmark the Draize data would be invaluable. The future use of Draize data in the validation of in vitro alternatives is undisputed, but the utility of these data will only be enhanced by a proper understanding of the shortcomings of the Draize test.

Animals↗
PubMedDate not supplied

Treatment of low back pain with intraspinal opioids delivered via implanted pumps.

Low back pain, more recently defined as "failed back surgery syndrome" is a common, yet devastating, pain complaint. Although physical therapy and systemic analgesics provide relief in most patients, intraspinal opioids delivered via implanted pumps may be indicated in those individuals who cannot tolerate oral medications. Orthopaedic nurses are essential in the identification and care of patients who might benefit from this therapy.

Aged↗