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Biomedical subjects

J S Lewis

Publications and source records attributed to J S Lewis.

At least 55 records · Page 3Linked to original sources
PubMed1998

Increase in endocervical CD4 lymphocytes among women with nonulcerative sexually transmitted diseases.

To assess associations of nonulcerative sexually transmitted diseases (STDs) with human immunodeficiency virus (HIV)-susceptible leukocytes on female genital mucosa, cervicovaginal specimens from 32 HIV-negative STD clinic patients with gonorrhea, chlamydial infection, or trichomoniasis were compared with specimens from 32 clinic patients without these infections. Twenty-eight patients had single infections (15 gonorrhea, 10 chlamydial infection, 3 trichomoniasis), and 4 had dual infections. A saline vaginal wash and saline suspensions of vaginal wall scrapings, ectocervical scrapings, and endocervical brushings were analyzed by flow cytometry. Specimens from the endocervix had the highest proportions of lymphocytes, monocytes, and Langerhans' cells. The median number of endocervical CD4 lymphocytes/10,000 cells was greater among patients with STDs than among those without (476 vs. 245; P < .001). These data suggest that the endocervix may have a particularly important role in heterosexual HIV transmission and that nonulcerative STDs may facilitate HIV transmission by increasing the presence of CD4 lymphocytes at this site.

Adolescent↗
PubMed1998

An investigation of genital ulcers in Jackson, Mississippi, with use of a multiplex polymerase chain reaction assay: high prevalence of chancroid and human immunodeficiency virus infection.

In 1994, an apparent outbreak of atypical genital ulcers was noted by clinicians at the sexually transmitted disease clinic in Jackson, Mississippi. Of 143 patients with ulcers tested with a multiplex polymerase chain reaction (PCR) assay, 56 (39%) were positive for Haemophilus ducreyi, 44 (31%) for herpes simplex virus, and 27 (19%) for Treponema pallidum; 12 (8%) were positive for > 1 organism. Of 136 patients tested for human immunodeficiency virus (HIV) by serology, 14 (10%) were HIV-seropositive, compared with none of 200 patients without ulcers (P < .001). HIV-1 DNA was detected by PCR in ulcers of 6 (50%) of 12 HIV-positive patients. Multivariate analysis indicated that men with chancroid were significantly more likely than male patients without ulcers to report sex with a crack cocaine user, exchange of money or drugs for sex, and multiple sex partners. The strong association between genital ulcers and HIV infection in this population highlights the urgency of preventing genital ulcers in the southern United States.

Chancroid↗
PubMed1998

New techniques and instruments for lens implantation.

Although no major breakthroughs have recently emerged in the area of lens insertion techniques and technology, small incremental advancements continue to take place for the placement of foldable intraocular lenses through small incisions. Folders have become more innovative in their ability to effectively fold lenses, and inserters have been downsized and enhanced to allow insertion through smaller incisions with more effective purchase of the lens. New cartridge injectors are increasing in popularity because of their ease of use and ability to pass through smaller incisions, especially with modifications. In addition, increased knowledge regarding techniques and complications of noncapsular supported intraocular lenses continues to be gained, adding to our ability to choose the proper technique for secondary lens insertion in these selected patients.

Equipment Design↗
PubMed1998

Radiotherapy, toxicity and dosimetry of copper-64-TETA-octreotide in tumor-bearing rats.

UNLABELLED: The efficacy of 64Cu [T1/2 = 12.7 hr; beta+ (0.655 MeV; 19%); beta- (0.573 MeV; 40%)] as a radioisotope for radiotherapy has been recently established. Here we demonstrate that 64Cu-1,4,8,11 -tetraazacyclotetradecane-N,N',N",N'''-tetraacetic acid (TETA)-octreotide, a somatostatin receptor ligand, inhibits the growth of CA20948 rat pancreatic tumors in Lewis rats at doses that cause minimal toxicity. METHODS: Tumor-bearing rats were administered a single 15 mCi (555 MBq) dose, a fractionated dose of 15 mCi given in 2-3 doses over 2-8 days, or control agents of buffer, unlabeled octreotide or 64Cu-labeled TETA. In certain experiments, blood was removed at times from 4-23 days post-treatment, and a complete blood count along with blood chemistry analyses were obtained. RESULTS: Tumor-growth inhibition was significantly greater in rats injected with a single 15 mCi dose than in rats injected with control agents (p < 0.05). Dose fractionation in two doses, either 1 or 2 days apart, induced significantly increased tumor-growth inhibition compared with rats given a single dose (p < 0.05). The only toxicity observed in treated rats was a decrease in the white blood cell count. This drop was more pronounced in rats treated with a single dose compared with those treated with a fractionated dose. Human absorbed doses of 64Cu-TETA-octreotide to normal organs were estimated from biodistribution data in Lewis rats, and these data indicate that radiotherapy with 64Cu-TETA-octreotide in humans would be feasible. CONCLUSION: Copper-64-TETA-octreotide is a promising radiopharmaceutical for targeted radiotherapy of somatostatin receptor-positive tumors.

Animals↗
PubMed1997

Effects of natural and synthetic polyamines on the conformation of an oligodeoxyribonucleotide with the estrogen response element.

We studied the effects of natural and synthetic polyamines on the conformation of an oligodeoxyribonucleotide (ODN1) harboring the estrogen response element (ERE) by circular dichroism (CD) spectroscopy and polyacrylamide gel electrophoresis. Putrescine and spermidine had no marked effect on the CD spectrum of ODN1. In contrast, spermine provoked and stabilized two characteristic changes in the CD spectrum. The first change was indicated by an increase in the intensity of the CD band at 280 nm at 0.5 mM spermine in Tris-HCl buffer containing 50 mM NaCl. This change appears to be related to changes in base tilt and conformational alterations similar to A-DNA. At 1-2 mM spermine, the CD spectrum was characterized by a loss of positive bands at 220 and 270 nm. This change might have contributions from polyamine-induced condensation/aggregation of DNA. Spectral measurements were also conducted in Tris-HCl buffer containing 150 mM NaCl to minimize contributions from condensation and aggregation of ODN1. Under these conditions, CD spectral changes were retained by (ODN1), although the magnitude of the change was diminished. In contrast, a control oligdeoxyribonucleotide (ODN2) having similar base composition did not show any significant change in the CD spectrum in the presence of 150 mM NaCl and 2 mM spermine. The changes in the CD spectrum of ODN1 were highly sensitive to polyamine structure, as evidenced by experiments using spermine analogs with altered number of -CH2- groups separating the amino and imino groups. Electrophoretic mobility shift analysis further showed ODN1 stabilization by spermine and its analogs. These data demonstrate the ability of an ODN containing ERE to undergo conformational transitions in the presence of polyamines and suggest a possible mechanism for polyamine-mediated alterations in the interaction of estrogen receptor with ERE.

Base Sequence↗
PubMed1996

Copper radionuclides and radiopharmaceuticals in nuclear medicine.

The chemistry, radiochemistry, radiobiology, and radiopharmacology of radiopharmaceuticals containing copper radionuclides are reviewed. Copper radionuclides offer application in positron emission tomography, targeted radiotherapy, and single photon imaging. The chemistry of copper is relatively simple and well-suited to radiopharmaceutical application. Current radiopharmaceuticals include biomolecules labelled via bifunctional chelators primarily based on cyclic polyaminocarboxylates and polyamines, and pyruvaldehyde-bis(N4-methylthiosemicarbazone) (PTSM) and its analogues. The chemistry of copper, of which only a fraction has yet been exploited, is likely to be applied more fully in the future.

Animals↗
PubMed1995

The use of a bilobed flap in the correction of radial club hand.

A new incision is described for the correction of radial club hand. By the use of a bilobed flap, redundant skin is transferred from the ulnar side of the wrist to the radial side, where there is tension as the wrist becomes straight. The flap has been shown to be safe and effective in six consecutive cases, and access to the wrist and surrounding soft tissue structures is excellent.

Adolescent↗
PubMed1995

New techniques and instruments for lens implantation.

Although most of the new techniques and new instrumentation for intraocular lens implantation are related to foldable intraocular lenses or sutured posterior chamber lenses, there are some intriguing new concepts in intraocular lens techniques unrelated to these two areas.

Cataract Extraction↗
PubMed1993

Sulcus fixation without flaps.

BACKGROUND: Numerous techniques for sulcus fixation of posterior chamber implants in the absence of capsular support have been reported. All rely on partial thickness scleral flaps or the conjunctiva to prevent the requisite polypropylene knot from eroding. The author compares their success with that of a new surgical procedure. This new technique buries the knot within the eye. METHODS: One hundred scleral-sutured, sulcus-fixated cases were studied retrospectively. Each case was performed by the author or by a resident under this direction. Suture erosion was defined as the absence of scleral or conjunctival cover on part of the polypropylene suture. RESULTS: On 60 patients, partial thickness scleral flaps were used to protect the knot from exposure. Twelve (20%) of these patients had some degree of externalization of the suture. Of the 40 patients in whom knots were buried and no scleral flap was used, no (0%) erosion was observed. CONCLUSION: Sulcus fixation of posterior chamber knots has been criticized for increasing the risk of endophthalmitis. The track formed by an exposed suture allows an infectious agent to pass from the external eye to the supported intraocular lens (IOL). Scleral flaps add a degree of safety, but the knot can erode after several months. The author advocates burying the knot within the eye to avoid erosion and therefore endophthalmitis.

Aged↗
PubMed1993

Direct DNA probe assay for Neisseria gonorrhoeae in pharyngeal and rectal specimens.

The direct detection of gonococcal DNA in rectal and pharyngeal specimens was evaluated by using a DNA probe-based assay (Gen-Probe, Inc., San Diego, Calif.). Rectal (234) and pharyngeal (608) swab specimens were obtained from 249 men and 372 women attending sexually transmitted disease clinics in Las Vegas and Reno, Nevada. The prevalence of gonococcal infection by culture at the pharyngeal and rectal sites was 2.9% (16 of 548 specimens) in women and 2.7% (8 of 294 specimens) in men. No false-positive reactions were observed among the 234 rectal specimens tested. Two probe-positive, culture-negative specimens were detected among the 361 pharyngeal specimens obtained from women. Both of these samples were confirmed as Neisseria gonorrhoeae by a probe competition assay. The overall correlation of the DNA probe test with pharyngeal and rectal cultures was 99.4% (837 of 842 cultures), with a sensitivity of 87.5% (21 of 24 cultures) and specificity of 99.7% (816 of 818 cultures). The positive and negative predictive values of the DNA assay were 91.3 and 99.8%, respectively. The direct DNA probe assay provides an alternative to culture screening for rectal and/or pharyngeal gonococcal infections.

DNA Probes↗
PubMed1993

Evaluation of the PACE 2 Neisseria gonorrhoeae assay by three public health laboratories.

The Gen-Probe PACE 2 DNA probe assay for Neisseria gonorrhoeae was compared with conventional culture techniques in three Florida public health laboratories with 436 patients (271 females and 165 males). The prevalence rates based on culture were 19.9, 55.8, and 33.5% for females, for males, and overall, respectively. Twenty-seven probe-positive specimens gave negative culture results. Twenty of these specimens were resolved as true positives after retesting with a probe competition assay. The resolved sensitivity, specificity, positive predictive value, and negative predictive value were 99.4, 99.6, 99.4, and 99.6%, respectively.

DNA Probes↗
PubMed1993

Assessing physician variability in parenteral nutrition orders given a set of patient parameters as a means of determining educational needs.

Diversity of physician training and experience results in variability of physicians' assessments of total parenteral nutrition needs for patients. The Surgery, Medicine, and Medicine Intensive Care team members at the Walter Reed Army Medical Center, Washington, DC, were asked individually to prescribe a parenteral nutrition order for a hypothetical patient with a given set of characteristics and laboratory parameters. The parenteral nutrition order form used provided the options of individualized or standardized total nutrient admixture/peripheral parenteral nutrition formulas. The variability of these orders was assessed and used as a basis for medical team education and individual prescriber counselling.

Adult↗
PubMed1993

Drafting a parenteral nutrition order form utilizing a physician assessment process.

The utilization of a physician critique process in the design of a parenteral nutrition order form, encouraging a standard order option, is assessed. In the critique process, physicians from surgery, medicine, and medical intensive care teams were tasked to use the draft order form and guideline sheet to prescribe a parenteral nutrition order for a hypothetical patient. Prescriber recommendations and problems with the nutrition order form and guideline sheet directed editorial improvements. The physician assessment process is an effective means to measure utility of a draft parenteral order form and prescribing guideline sheet. By utilizing physician expertise, deficiencies inherent in such an order form may be corrected prior to implementation.

Drug Prescriptions↗
PubMed1992

Urinary leukocyte esterase test: a screening method for the detection of asymptomatic chlamydial and gonococcal infections in men.

The ability of a urinary dipstick leukocyte esterase test (LET) to predict culture-verified asymptomatic urethral infections of Chlamydia trachomatis and Neisseria gonorrhoeae was determined in 1095 men (aged 18-39) who presented to an urban hospital for acute general medical care. Prevalence of chlamydial and gonococcal infections were 4% and 2.5% respectively; LET sensitivity was 41% and specificity was 91%. In the youngest one-third, the prevalence of infection and LET sensitivity and specificity increased to 9%, 58%, and 93%, respectively. Higher inclusion count in chlamydia culture was also significantly correlated with younger age. This is the first study to assess LET performance as a screening test for asymptomatic disease in adult men and suggests that LET has promising accuracy in young men but is less likely to be a useful screening test in men greater than 25 years old.

Adult↗