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Biomedical subjects

L W Jones

Publications and source records attributed to L W Jones.

At least 19 recordsLinked to original sources
PubMed2003

In vitro uptake and release studies of ocular pharmaceutical agents by silicon-containing and p-HEMA hydrogel contact lens materials.

The in vitro uptake and release behaviour of cromolyn sodium, ketotifen fumarate, ketorolac tromethamine and dexamethasone sodium phosphate with silicon-containing (lotrafilcon and balafilcon) and p-HEMA-containing (etafilcon, alphafilcon, polymacon, vifilcon and omafilcon) hydrogel contact lenses indicated that both drug and material affected the uptake and release behaviour. Rapid uptake and release (within 50 min) was observed for all drugs except ketotifen fumarate which was more gradual taking approximately 5h. Furthermore, the maximum uptake differed significantly between drugs and materials. The highest average uptake (7879+/-684 microg/lens) was cromolyn sodium and the lowest average uptake (67+/-13 microg/lens) was dexamethasone sodium phosphate. Partial release of the drug taken up was observed for all drugs except dexamethasone sodium phosphate where no release was detected. Sustained release was demonstrated only by ketotifen fumarate. Drug uptake/release appeared to be a function of lens material ionicity, water and silicon content. The silicon-containing materials released less drug than the p-HEMA-containing materials. The lotrafilcon material demonstrated less interactions with the drugs than the balafilcon material which can be explained by their different bulk composition and surface treatment.

Adsorption↗
PubMed2003

A randomized trial of exercise and quality of life in colorectal cancer survivors.

We conducted a randomized controlled trial to determine the effects of a home-based exercise intervention on change in quality of life (QOL) in recently resected colorectal cancer survivors, most of whom were receiving adjuvant therapy. Participants were randomly assigned in a 2:1 ratio to either an exercise (n = 69) or control (n = 33) group. The exercise group was asked to perform moderate intensity exercise 3-5 times per week for 20-30 min each time. The primary outcome was change in QOL as measured by the Functional Assessment of Cancer Therapy-Colorectal (FACT-C) scale. Adherence in the exercise group was good (75.8%) but contamination in the control group was problematic (51.6%). Intention-to-treat analysis revealed no significant differences between groups for change in the FACT-C (mean difference, -1.3; 95% CI, -7.8 to 5.1; P = 0.679). In an 'on-treatment' ancillary analysis, we compared participants who decreased versus increased their cardiovascular fitness over the course of the intervention. This analysis revealed significant differences in favour of the increased fitness group for the FACT-C (mean difference, 6.5; 95% CI, 0.4-12.6; P = 0.038). These data suggest that increased cardiovascular fitness is associated with improvements in QOL in colorectal cancer survivors but better controlled trials are needed.

Colorectal Neoplasms↗
PubMed2003

Ciprofloxacin interaction with silicon-based and conventional hydrogel contact lenses.

PURPOSE: Hydrogel contact lenses can be used as bandage lenses to protect the corneal surface after injury. The use of novel silicon-based hydrogel lens materials as bandage lenses has not gained widespread acceptance. As a first step toward advocating their usefulness as bandage lenses, their interaction with ocular pharmaceuticals must be understood because topical agents are often administered in conjunction with bandage lenses. METHODS: The in vitro uptake and release of ciprofloxacin from silicone-based hydrogel (SH) and conventional pHEMA-based (CH) hydrogel contact lenses was examined by spectrophotometric evaluation of the drug concentration in saline solution. RESULTS: The hydrogel contact lenses tested showed similar drug uptake (average 1800 microg/lens) but different levels of drug release. Multiphoton laser microscopy indicated that ciprofloxacin was distributed throughout the lens thickness, with higher levels of drug at the surface owing to drug precipitation. The drug adsorption onto the lenses was partially reversible. The SH lenses released a lower amount of drug than CH lenses (72 vs. 168 microg/lens). Ionic lenses released less drug than non-ionic lenses (127 vs. 151 microg/lens). CONCLUSIONS: The differences in ciprofloxacin uptake and release between SH and CH materials may not be clinically significant because the amount of drug released from all lenses would be above the MIC(90) of ciprofloxacin for common ocular pathogens. These results indicate that material properties have a significant impact on drug-lens interactions.

Adsorption↗
PubMed1995

Studies of rhodamine-123: effect on rat prostate cancer and human prostate cancer cells in vitro.

The effect of the lipophilic, cationic dye, Rhodamine-123 (Rh-123), on prostate cancer in rats, and on three tumor cell lines in vitro is reported here. The general toxicity of Rh-123 in mice has been found to be minimal. Lobund-Wistar (L-W) rats with the autochthonous prostate cancer of Pollard were treated for six doses with Rh-123 at a dose of 15 mg/kg subcutaneously every other day. Microscopic examination of the tumors revealed cellular and acinar destruction. The effectiveness of Rh-123 as a cytotoxic agent was tested by clonogenic and viability assays in vitro with three human prostate cancer cell lines. Severe (60-95%) growth inhibition was observed following Rh-123 exposure for 2-5 days at doses as low as 1.6 micrograms/ml in all three prostate cancer cell lines.

Adenocarcinoma↗
PubMed1994

Management development: preparing nurse managers for the future. Part 1, Program model.

Nurse executives need to develop programs to help nurse managers meet rapidly changing role expectations and prepare for new healthcare challenges. This two-part series reports on one such program for nurse managers at The Johns Hopkins Hospital. Part 1 describes the program model, its conceptual framework, and its various components. Part 2 will present an in-depth evaluation of the program and recommendations for future development.

Baltimore↗
PubMed1991

Perineal injuries in children.

Over a 12-year period, 463 children under 13 years of age were treated for perineal injuries. The most common cause of injury was a fall astride, but motor vehicle trauma and rape were responsible for most of the severe and multiple injuries. Physical or sexual abuse was evident in 178 (38 per cent) of children, and four sustained injuries from forceful enema. Minor abrasions or first degree tears (88 per cent) and second degree tears (6 per cent) were sutured primarily or allowed to granulate with sepsis rates of 1.2 per cent and 14 per cent respectively. Twenty-nine (6 per cent) children sustained third degree lacerations; one died from secondary pelvic haemorrhage. In the 28 survivors, the outcome of primary (18) or delayed (ten) surgical repair was related to whether or not early defunctioning colostomy had been performed.

Accidents, Home↗
PubMed1991

Image guided localized 31P magnetic resonance spectroscopy of acute urinary tract obstruction.

Using 31P magnetic resonance spectroscopy, localized spectroscopy and magnetic resonance imaging we studied effects of acute urinary obstruction in the in vivo pig kidney. Accumulation of urine in the renal pelvis and collecting ducts resulted in the appearance of a new peak in the localized phosphorus spectra originating in the renal papilla, resonating at 3.43 to 4.56 ppm. This was inorganic phosphate with a pH of 5.60 to 6.79 (urine pH). Imaging did not show any dilatation of renal pelvis. There was a significant time dependent fall in renal [ATP] during urinary obstruction followed by a rapid "overshoot" of [ATP] and disappearance of the phosphate peak after release of obstruction. Possible mechanisms for this phenomenon are discussed. We conclude that 31P magnetic resonance spectroscopy provides early evidence of urinary obstruction in vivo and could be of value in clinical diagnosis.

Animals↗
PubMed1991

Possible allergic reactions to cyclopentolate hydrochloride: case reports with literature review of uses and adverse reactions.

Cyclopentolate has been widely used as a cycloplegic and mydriatic agent for over 30 years. It has gained widespread use as the cycloplegic drug of first choice for most children over the age of 1 year and allows many optometrists and ophthalmologists to carry out quick, successful cycloplegic refractions with few complications. During this time very few side-effects have been reported with the most commonly used 1% solution. This paper outlines two cases in which a possible allergic-type reaction occurred shortly after the instillation of 1% cyclopentolate hydrochloride in 'Minims' form (Smith and Nephew). This article also reviews the uses and side-effects of cyclopentolate and aims to warn practitioners about the possibility of such reactions, ways of avoiding their occurrence and suitable measures to take should they occur.

Child↗
PubMed1990

Metabolic effects of sodium nitroprusside on the pig kidney in vivo: studies by phosphorus-31 magnetic resonance spectroscopy.

Phosphorus-31 magnetic resonance spectroscopy was applied to the pig kidney in vivo to determine the metabolic effects of infusion of sodium nitroprusside, and of more severe hypotension produced by venesection or halothane. Sodium nitroprusside 7-20 micrograms kg-1 min-1 reduced mean systemic arterial pressure (AP) of the pig from 89 to 46 mm Hg. Glomerular filtration rate and total sodium reabsorption were reduced proportionally. Renal metabolism, assessed by the ratio [ATP]: [Pi] (inorganic phosphate), did not change. Adding halothane or venesection to nitroprusside hypotension caused a further reduction in systemic AP to 42 and 39 mm Hg, respectively. Renal [ATP] decreased in direct proportion to mean AP. It is concluded that sodium nitroprusside, even in high doses, does not reduce renal oxygen delivery as assessed by the ability of the kidney to maintain normal ATP content. However, haemorrhage or an increase in halothane dosage results in irreversible damage to the energy producing processes of the kidney. This may be relevant to the clinical use of the drug.

Adenosine Triphosphate↗
PubMed1989

Differentiation between renal cortex and medulla in the response to hypotension using localized 31P magnetic resonance spectroscopy.

Experiments were designed to test the hypothesis that renal medulla is more sensitive to hypoxia than is the cortex. Using the one-dimensional phase encoding technique to perform 31phosphorus magnetic resonance spectroscopy in a perfused porcine kidney preparation, cortex and medulla were differentiated on the basis of the unique resonance at 3 ppm found only in medulla. Hypotension-induced hypoxia reduced total renal oxygen consumption by 60%, and urine flow by 44%. Nonlocalized 31P MRS spectra showed that [ATP]/[Pi] ratio fell by 40%, and intrarenal pH by 0.1 unit. Virtually all of these changes could be accounted for by changes in the renal cortex, where initial [ATP]/[Pi] was higher than in medulla (1.16 vs. 0.68). In medulla [ATP]/[Pi] fell only 29% (n.s. versus control) and pH remained unchanged during hypotension. Thus the cortex appears to be more sensitive to hypoxia in this preparation, and observations fail to support the proposed hypothesis. They are consistent, however, with the greater capacity of medulla for anaerobic glycolysis. Localized 31P MRS provides improved noninvasive metabolic assessment of cold-preserved kidneys.

Adenosine Triphosphate↗
PubMed1988

Nuclear magnetic resonance imaging in detecting and staging prostatic cancer.

Thirteen patients were examined for grade, stage, and extent of their prostatic cancer, utilizing nuclear magnetic resonance imaging (MRI) and clinical workup for metastases. Of these 13 patients, 12 had known prostatic cancer proved by needle biopsy or by pathologic examination of transurethral prostatectomy tissue. Five of these patients underwent radical surgery allowing further correlation of clinical findings and MRI data with the surgical pathologic findings. MRI of the prostate was found to be a sensitive modality in detecting prostatic carcinoma and showing extension of disease in some cases. Also, in some cases it was not always possible to differentiate between prostatic carcinoma and benign prostatic hyperplasia with MRI.

Aged↗
PubMed1985

Selective growth of normal adult human urothelial cells in serum-free medium.

A serum-free medium (HMRI-2) has been developed for the outgrowth and subculture of epithelial cells from normal adult human ureter and bladder. Medium HMRI-2 consists of Ham's MCDB 152 with double the amounts of the essential amino acids in Stock 1, low Ca2+ (0.06 mM) and is supplemented with epithelial growth factor, 5 ng/ml; transferrin, 5 micrograms/ml; insulin, 5 micrograms/ml; ethanolamine and phosphoethanolamine, 0.1 mM each; hydrocortisone, 2.8 X 10(-6) M; and bovine pituitary extract, 126 micrograms protein/ml. The cultured cells showed ultrastructural markers of epithelial cells (prekeratin fibers, tonofilaments, surface microvilli with glycocalyx), exhibited ABO antigens, and had a normal human diploid karyotype. Primary cultures could be subcultured and also cryopreserved in HMRI-2 in liquid nitrogen. Cells in mass cultures showed a population doubling time of 40.5 +/- 4.5 h and had a maximum in vitro life span of 20 to 25 population doublings. It was observed that primary outgrowths, secondary cultures, and even cryopreserved cells all retained the capacity to respond to high Ca2+ and serum by differentiation and desquamation. This study has resulted in the availability of easily obtainable serum-free epithelial cultures from normal adult human ureter and bladder. The useful in vitro life span of these cultures may be important in future studies of carcinogenesis.

Adolescent↗
PubMed1985

Growth of a malignant human urothelial cell line (J82) in a serum-free medium (HMRI-1) developed previously for normal human urothelium.

A malignant human urothelial cell line (J82) has been cultured in a serum-free medium (HMRI-1) developed specifically for normal human urothelium. Unlike the normal human urothelium which grew as an attached monolayer, the J82 cells proliferated as free floating cellular aggregates. Comparative growth kinetic studies have shown that the J82 cells, unlike normal cultured urothelial cells, did not require epidermal growth factor, bovine pituitary extract or transferrin as single additives in the HMRI-1. However, deletion of certain combinations of these factors markedly reduced growth. It was concluded that the J82 cells had a reduced dependency on the normal urothelial cell growth factors suggesting that the J82 cells had altered nutritional requirements which might possibly be associated with the production of autocrine growth factors.

Carcinoma, Transitional Cell↗
PubMed1982

Autogenous vaccine therapy for condyloma acuminatum. A double-blind controlled study.

In an attempt to substantiate claims that autogenous vaccine is an effective form of immunotherapy for condyloma acuminatum, a double-blind cross-over study was carried out on 34 patients, in which autogenous wart vaccine was compared with a placebo vaccine identically prepared from each patient's own normal skin. It was found that the duration of disease was an important determinant of curability in patients with condylomata acuminata (P less than 0.001) and that when this factor was taken into account autogenous wart vaccine was not significantly more effective than the placebo (P = 0.43).

Anus Diseases↗
PubMed1982

Chromosomal instability of SV40-transformed human prostatic epithelial cell lines.

Three SV40-transformed derivatives (G1, T2, and T5) of human prostatic epithelial cells were analyzed karyotypically. For comparison, an SV40 derivative (TA) obtained from isogenic fibroblasts, was also studied. The chromosome complements of these cells, as well as a sub-clone of T2 isolated in soft agar (T2-A5), were analyzed using banding techniques. Numerical as well as structural changes were observed in all transformed cultures. Karyotypic changes in all cells at a given passage level appeared to be random. On the other hand, characteristic differences in modal chromosome number, and type and number of abnormal chromosomes were observed among the different lines. Most cells of two of the three epithelial lines (T1 and T2) were either hypo- or pseudodiploid, whereas T5 consisted of a mixed hypodiploid and hypotetraploid population. The TA subline was also predominantly hypo- and pseudodiploid. Dicentrics, telomeric associations, translocations, and loss of chromosomes were the most prominent abnormalities. The loss of chromosome 18 was characteristic for all epithelial lines. All T1 and T5 cells had lost either one or both copies of the 18. While individual cells of the original T2 line had random karyotypes, most of T2-A5 cells had a relatively uniform karyotypic pattern. They also had a similar pattern of abnormal chromosomes. These observations suggest that culture in soft agar may have selected a particular chromosomal variant. We conclude that transformation of prostatic epithelial cells by SV40 may bring about site-specific as well as random chromosomal changes. These changes could reflect either intermediate or sequential stages in progression to neoplasia.

Cell Line↗
PubMed1980

Differential properties among clones of simian virus 40-transformed human epithelial cells.

Monolayer cultures of human prostatic epithelial cells were exposed to SV40 virus at 35th population doubling. Clones were isolated from infected plates after growth had ceased on the control plates. The nuclei of these clones were virtually all positive for viral T-antigen by immunofluorescence. When the properties of three of these lines were compared to those of normal cells, they were found to have altered morphology, ultrastructure, chromosomes, and growth behavior. All transformed lines had reduced serum dependence and were capable of growing in soft agar. However, their reduced serum dependence was not due to reduced growth factor requirements because each subline's response to growth factors was different.

Agar↗