Search PubMed⌕ Search

Biomedical subjects

S Haines

Publications and source records attributed to S Haines.

12 recordsLinked to original sources
PubMed1998

Randomized trial of cerebrospinal fluid shunt valve design in pediatric hydrocephalus.

OBJECTIVE: Forty percent of standard cerebrospinal fluid shunts implanted for the treatment of pediatric hydrocephalus fail within the first year. Two new shunt valves designed to limit excess flow, particularly in upright positions, were studied to compare treatment failure rates with those for standard differential-pressure valves. METHODS: Three hundred-forty-four hydrocephalic children (age, birth to 18 yr) undergoing their first cerebrospinal fluid shunt insertion were randomized at 12 North American or European pediatric neurosurgical centers. Patients received one of three valves, i.e., a standard differential-pressure valve; a Delta valve (Medtronic PS Medical, Goleta, CA), which contains a siphon-control component designed to reduce siphoning in upright positions; or an Orbis-Sigma valve (Cordis, Miami, FL), with a variable-resistance, flow-limiting component. Patients were monitored for a minimum of 1 year. Endpoints were defined as shunt failure resulting from shunt obstruction, overdrainage, loculations of the cerebral ventricles, or infection. Outcome events were assessed by blinded independent case review. RESULTS: One hundred-fifty patients reached an endpoint; shunt obstruction occurred in 108 (31.4%), overdrainage in 12 (3.5%), loculated ventricles in 2 (0.6%), and infection in 28 (8.1%). Sixty-one percent were shunt failure-free at 1 year and 47% at 2 years, with a median shunt failure-free duration of 656 days. There was no difference in shunt failure-free duration among the three valves (P = 0.24). CONCLUSION: Cerebrospinal fluid shunt failure, predominantly from shunt obstruction and infection, remains a persistent problem in pediatric hydrocephalus. Two new valve designs did not significantly affect shunt failure rates.

Adolescent↗
PubMed1997

Spreading and retention of vaginal formulations in post-menopausal women as assessed by gamma scintigraphy.

PURPOSE: In this paper we report on the first scintigraphic evaluation of vaginal dosage forms in post-menopausal women. To date, almost nothing is known about the in vivo performance of pharmaceutical formulations in the human vagina, which is a major deficiency in the rational design of drug delivery systems for both existing and new indications. METHODS: The vaginal spreading and clearance of a radiolabelled pessary formulation and Replens (polycarbophil) gel, was assessed in six healthy, post-menopausal female volunteers over a six hour period using the technique of gamma scintigraphy. RESULTS: In five out of the six subjects studied, clearance of the two formulations exhibited very little intra-subject variation. However, there was considerable inter-subject variability in clearance; in Subject 5 circa 80% of the products were retained whilst in Subject 2 less than 2% was present at the end of the six hour imaging period. Importantly, there was no evidence to suggest that either of the formulations dispersed material beyond the cervix, into the uterus, in any of the subjects studied. CONCLUSIONS: The lack of significant retention of these products in most of the volunteers has obvious implications for the delivery of therapeutic agents. This study shows that gamma scintigraphy is an invaluable technique with which to assess novel formulations aimed at optimising retention in the vagina for topical or systemic drug delivery.

Administration, Intravaginal↗
PubMed1997

Colonic spread of three rectally administered mesalazine (Pentasa) dosage forms in healthy volunteers as assessed by gamma scintigraphy.

BACKGROUND: Rectal administration of enemas, foams and suppositories is the most efficient method of delivering locally-acting drugs to the distal colon, sigmoid colon and rectum. Healthy volunteers provide an effective population to compare different formulations for rectal drug delivery. However, there is still only limited comparative information available on the dispersion of such dosage forms in human subjects. Therefore, the objective of this scintigraphic study was to compare colonic spread of an enema, a rectal foam and a suppository formulation in healthy volunteers. METHODS: This was a randomized, crossover study in eight healthy male volunteers. Each received Pentasa rectal formulations as either a 100 mL suspension enema (1 g mesalazine), one actuation of a non-CFC propellant rectal foam (1 g mesalazine in 5 mL concentrate, expanding to 40 mL on actuation), or one suppository (1 g mesalazine) on three separate occasions. The spread of the radiolabelled formulations was assessed over a 4-h period by gamma scintigraphy. RESULTS: The formulations were retained by all subjects for the whole of the 4-h imaging period. The enema spread to the splenic flexure in 7 out of 8 subjects, but was retained in the rectum and sigmoid colon in one individual. The foam spread as far as the descending colon in four subjects. In the remaining individuals the foam was retained in the rectum and sigmoid colon. The spread of the suppository was limited and confined to the rectum. CONCLUSIONS: The findings of this study are consistent with previous research and support the intended clinical uses of the enema, foam and suppository formulations to treat distal ulcerative colitis, proctosigmoiditis and proctitis, respectively. The results highlight the potential of gamma scintigraphy in providing in vivo 'proof of concept' data to help verify the targeting of pharmaceutical products to their intended site of delivery.

Administration, Rectal↗
PubMed1995

Evaluating hearing threshold differences between ears as a screen for acoustic neuroma.

Differences in pure tone thresholds between ears were evaluated at two different patient care facilities to determine this measure's value as a screen for acoustic neuroma. We evaluated the audiograms of tumor and nontumor groups to estimate the true positive rates and false positive rates for several decision rules. Threshold differences were found to be a more effective diagnostic tool for females than for males. However, even for the most effective rules, the efficiency of this test alone is mediocre, which indicates that hearing threshold differences between ears must be combined with other criteria for a cost-effective approach to acoustic neuroma identification. Furthermore, tumor size was not predicted by the amount of threshold asymmetry between ears, which suggests that some large, potentially life-threatening tumors may be missed if pure tone threshold differences are the sole criterion for referral for additional tests.

Adult↗
PubMed1995

Prototype instruments for endoscopic microsurgery: technical note.

The authors describe a concept of converting microsurgical instruments into endoscopes and demonstrate prototype devices. These instruments combine the benefits of microsurgery (multiple instruments, tactile feedback, bimanual manipulation, magnification) with those of endoscopy (minimally invasiveness, indirect line of vision).

Animals↗
PubMed1994

VASE exon expression alters NCAM-mediated cell-cell interactions.

The neural cell adhesion molecule (NCAM) is found on cells as several related polypeptides formed by alternative splicing of the single NCAM gene. The alternatively spliced 30-bp VASE exon in the fourth immunoglobulin-like domain is the structural variation nearest those portions of the polypeptide proposed to mediate cell-cell adhesion. To test the ability of distinct forms of the NCAM molecules to mediate cell adhesion, L cells were transfected with expression vectors encoding rat 140 kD NCAM +/- the VASE exon. L cell lines which expressed these polypeptides were isolated and tested for self-aggregation in a low shear, rapid aggregation assay. Increased cellular aggregation of the transfectants was observed to be a function of the NCAM molecule expressed. These transfected cells showed segregation in a long term co-aggregation assay: cells expressing NCAM--VASE formed aggregates which tended to exclude cells expressing NCAM+VASE and vice versa. These results provide direct evidence that this small difference in NCAM structure is sufficient to allow segregation of cells.

Animals↗
PubMed1993

Axon growth is enhanced by NCAM lacking the VASE exon when expressed in either the growth substrate or the growing axon.

The neural cell adhesion molecule NCAM exists as several related peptides formed by alternative splicing of the single NCAM gene. Here the ability of NCAM containing and lacking the alternatively spliced VASE exon to act as a permissive growth substrate was tested by examining retinal axon outgrowth on normal L cell fibroblasts and L cells expressing stably transfected 140 kD NCAM +/- VASE. L cells expressing either NCAM form were a more permissive substrate than control L cells. At higher substrate cell densities, greater axon outgrowth occurred on substrate cells expressing NCAM - VASE than on those expressing NCAM + VASE. Similar experiments tested retinal axon growth on neuronal substrates by utilizing clonal B35 cells, C3 cells that are NCAM lacking variants of B35, and C3 cells into which 140 kD NCAM +/- VASE has been restored by transfection. Axon growth on C3 cells transfected with NCAM - VASE was greater than that on all other substrates including cells transfected with NCAM + VASE. In these experiments C3 cells and transfected C3 expressing NCAM + VASE cell promoted similar outgrowth. The influence on neurite growth of the NCAM isoform of the neurite itself was tested by examining neurite formation using combinations of C3 cells and C3 NCAM transfectants both in the growth monolayer and as responding cells. C3 cells were able to extend neurites, indicating NCAM is not required for neurite growth. However, C3 derivatives transfected with NCAM +/- VASE had greater neurite outgrowth. The most extensive neurite growth was found when NCAM - VASE was expressed by both substrate cells and the responding neurite growing cells. Thus NCAM enhances axon or neurite outgrowth when present either in the growth substrate or on the growing axon. NCAM - VASE has a significantly greater growth promoting capability than NCAM + VASE. The expression of NCAM + VASE by more mature neural cells could thus be a significant factor in the reduced axonation capabilities of mature neurons.

Animals↗
PubMed1993

Clinical management of a hemodialysis patient with metastatic hypernephroma receiving experimental alfa interferon therapy.

The nursing interventions needed to promote optimal care for D.S. forcefully reminded the nurses of the challenges of nursing practice. The physiologic and emotional impact of the disease processes (ESRD and cancer), and the nature of chronic illness with concurrent experimental interferon therapy required continuous attention as the combined therapies progressed. The goals and interventions outlined are familiar to nephrology nurses. They are very effective in assisting this patient to adjust and to meet the expected outcomes. The unique nature of every patient remains the constant in our clinical practice. Nursing must continue to forge ahead in assessing a patient's needs, but always remembering that these needs must support the patient's relationship with his/her world.

Carcinoma, Renal Cell↗
PubMedDate not supplied

Nurses for sale?

Explore the source record for details and available documents.

Humans↗