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Biomedical subjects

E Johnson

Publications and source records attributed to E Johnson.

At least 181 records · Page 10Linked to original sources
PubMed1996

Ovarian intraepithelial neoplasia and ovarian cancer.

Ovarian cancer accounts for only 4% of cancers in women, but it is the leading cause of death from gynecologic malignancies in the United States. In the general population, a woman's lifetime risk of ovarian cancer is 1.4% but this risk can increase substantially in women with a strong family history of the disease. The high mortality rate from ovarian cancer is due primarily to the difficulty in detecting the disease in early stages; the disease tends to be asymptomatic until it is well advanced. The primary care physician needs to be alert to the possibility of an ovarian malignancy in all women with an intact ovary or ovaries who present with abdominal or pelvic complaints. There are no current recommendations for routine screening for ovarian cancer in the general population. Even in high-risk women, there are currently no convincing data to support extensive screening, although a number of studies looking at this issue are under way. Despite this lack of conclusive evidence, a consensus panel on ovarian cancer convened by the NIH recently issued guidelines for screening high-risk women. They recommend annual rectovaginal pelvic examination, testing of CA 125 level, and transvaginal ultrasonography. Color flow Doppler analysis of the ovarian vessels is also being studied as a possible screening modality. BRCA1 gene testing may soon play a role in women with a strong family history of the disease. Given its high mortality rate, primary prevention strategies for ovarian cancer should be used whenever possible. Oral contraceptive use appears to reduce the risk of ovarian cancer. Prophylactic oophorectomy may be suggested for women at particularly high risk of the disease. Here, too, the primary care physician can play an important role in helping a patient understand the risks and benefits of these options.

Biomarkers, Tumor↗
PubMed1996

Gestational trophoblastic disease.

GTD occurs in fewer than 1 in 1200 pregnancies in the United States, but it is much more common in Asia and Latin America, where its incidence may be as high as 1 in 200 pregnancies. Risk factors for GTD include advanced or young maternal age, low socioeconomic status, and prior hydatidiform mole. Early diagnosis and prompt treatment are key to a favorable outcome, and thus recognition of the signs and symptoms of the disease is important for all physicians. Because these diseases have low incidences and occur after reproductive events, screening for them in the general population is not worthwhile. No chemopreventive agents have yet been studied in women at risk for GTD, but the oral contraceptive is a good candidate.

Biomarkers, Tumor↗
PubMed1996

Preliminary experience of infusional brachytherapy using colloidal 32P.

In the past, we have clinically evaluated radiolabelled antibodies in Hodgkin's disease and hepatocellular cancer. Increased tumour pressure, reduced vascularity and poor diffusion has limited significant radiolabelled antibody tumour dose deposition. Using intratumoural infusion of macroaggregated albumin to blockade exiting vasculature followed by colloidal chromic 32Phosphorous, we have been able to achieve 75% to 100% tumour dose deposition by interstitial tumour infusion under computerised tomographic guidance. Phase I studies in a variety of solid tumours indicate extremely high doses may be achieved without toxicity (i.e. non-resectable pancreas 900,000 cGy to 1.7 million cGy) with tumour control and remission. This is a review of those studies and how the technique was applied.

Astrocytoma↗
PubMed1996

Widespread HIV counseling and testing linked to a community-based tuberculosis control program in a high-risk population.

The aim of the work reported here was to evaluate community-wide screening for HIV infection that was linked to a tuberculosis control program in a population at high risk for both infections. Between May 1990 and August 1992, adults in Cité Soleil, Haiti, were recruited by community health workers at their homes and in clinics for individual, clinic-based counseling and testing for HIV and tuberculosis. All of the screened subjects were offered post-test HIV counseling. Those with active tuberculosis received treatment, while those with latent tuberculosis and HIV infection were offered an opportunity to participate in a trial of antituberculosis chemoprophylaxis. The 10,611 individuals screened for HIV represented 10.0% of the adult population in Cité Soleil. HIV infection was detected in 1,629 (15.4%) and active tuberculosis in 242 (2.3%). Latent M. tuberculosis infection was found in 4,800 (67.5%) of 7,309 community residents who completed tuberculosis screening, 781 (16.3%) of whom were coinfected with HIV. The high prevalence of HIV infection found in this screened population, as compared to other groups undergoing HIV screening in the same community, suggests that people at high risk for HIV infection selectively sought or accepted tuberculosis clinic screening. Also, many people with active tuberculosis were identified earlier in the course of their disease than they would have been in the absence of a screening program. Overall, the results indicate that community-based screening for HIV infection within a tuberculosis control program can result in effective targeting of screening for both infections.

Adolescent↗
PubMed1995

Postnatal growth of lung parenchyma in the piglet: morphometry correlated with mechanics.

BACKGROUND: A previous study of piglet lung growth (Mansell et. al. 1989. J. Appl. Physiol., 67:1422-1427) showed transient stiffness to changes in shape and volume immediately after birth. Later, elastic recoil was found to increase as the lung grew in weight and volume. The present study uses morphometry to test possible structural correlates of these two mechanical changes. METHODS: Piglet lungs were fixed near full inflation via the airways during the immediate newborn period (6-12 hours, n = 3), at 3-5 days (n = 6), 25-30 days (n = 5), and 80-85 days (n = 3). Morphometry comprised arithmetic and harmonic mean thicknesses of alveolar septae and average mean surface curvature. Measurements of curvature and airspace volume were combined to differentiate alveolar expansion from septal proliferation as mechanisms for volumetric growth. RESULTS: The unique mechanical behavior of the newborn lungs was associated with relatively thick alveolar septae. Marked thinning of the septae and resolution of the stiffness to shape and volume change had occurred by 3-5 days. An increase in elastic recoil during the first postnatal month was found to be associated with simple airspace expansion. The second and third months were characterized by septal proliferation and increase in arithmetic mean septal thickness but elastic recoil did not increase further. Harmonic mean septal thickness and airspace volume per gram of lung tissue did not change over the course of the study. CONCLUSIONS: 1) A relative stiffness to shape and volume change in freshly newborn piglet lungs is associated with relatively thick alveolar septal walls; 2) postnatal development of piglet lung parenchyma involves septal lengthening and thinning followed by septal proliferation; 3) the initial phase of septal lengthening, rather than the later phase of septal proliferation, is associated with increase in parenchymal recoil.

Animals↗
PubMed1995

Xenopus F-cadherin, a novel member of the cadherin family of cell adhesion molecules, is expressed at boundaries in the neural tube.

Development of the vertebrate CNS begins during neurulation when the neural plate gives rise to the neural tube. During neurulation, the different regions of the CNS can be identified in part by the appearance of flexures in the walls of the neural tube. Here we report the isolation and characterization of F-cadherin; a novel member of the cadherin family of cell adhesion molecules, which is expressed at flexures in the neural tube of Xenopus embryos. We show that F-cadherin is first expressed at neural plate stages, that its expression is altered when patterning of the neural tube is perturbed, and that its expression marks boundaries in the neural tube where cell mixing is restricted. These observations suggest that F-cadherin contributes to the regionalization of the neural tube perhaps by mediating differential cell adhesion.

Amino Acid Sequence↗
PubMed1995

Novel insertion sequence-like element IS982 in lactococci.

A novel insertion sequence-like (IS) element, designated IS982, was found on the lactose plasmid, pSK11L, from Lactococcus lactis subsp. cremoris SK11 and was located between the origin of replication and the oligopeptide transport gene cluster. The 1003-base pair (bp) IS982 was flanked by 18-bp perfect inverted repeats. IS982 contained an open reading frame encoding a putative transposase of 296 amino acids. An almost identical IS-like element (99% DNA sequence identity) was cloned and partially sequenced from the chromosome of Lactococcus lactis subsp. cremoris Wg2 with 17-bp perfect inverted repeats. Southern analysis indicated that in 12 lactococcal strains examined, IS982 was present with copy numbers ranging from 1 to at least 20. IS982 displayed sequence homology to the putative IS element RSBst-alpha from Bacillus stearothermophilus CU21, IS982 and RSBst-alpha were not related to other known insertion sequences and may represent a new family of IS elements.

Amino Acid Sequence↗
PubMed1995

Measuring health-related quality of life in persons with genital herpes.

A disease-specific measure was needed for use in an international clinical trial to evaluate an investigational drug for genital herpes. A new measure was developed initially in the UK and translated and adapted for use in France, Italy, Germany, Denmark, Spain and the USA. This paper describes the translation and adaptation of the USA measure. It also describes the assessment of internal consistency, reproducibility, content validity, and construct validity (convergent and discriminant) of the measure. Two outcome measures of the final genital herpes-specific measure were developed: (1) a 21-item symptoms subscale; and (2) a 20-item HRQOL subscale. Each measure was scored and analyzed separately; the psychometric testing discussed in this paper refers to the HRQOL subscale only. The internal consistency of the HRQOL subscale is high (r = 0.93), as is the reproducibility measured with a two week interval (r = 0.85). Convergent validity is moderate to high. (Fleming Self-Regard subscale, r = 0.48; SF-36 Social Functioning dimension r = 0.59; SF-36 Mental Health dimension r = 0.50). The number of herpes outbreaks in the past year was a significant predictor of scores on the HRQOL subscale (0-1 outbreaks, mean = 82.1; 2+ outbreaks, mean = 72.1, p = 0.058) suggesting discriminant validity. The measure is currently in a phase III clinical trial including anti-viral therapy where the question of responsiveness can be addressed.

Adult↗
PubMed1995

Structure and composition of the rodent lamina cribrosa.

To define the architecture and extracellular matrix composition of the lamina cribrosa in rodents, normal, adult pigmented rat and guinea pig eyes were frozen and sectioned for light microscopic immunohistochemistry. Antibodies specific for collagens I, III, IV and VI, laminin, elastin, and chondroitin and dermatan sulfate proteoglycans were exposed to longitudinal and cross-sections of optic nerve heads and their binding distributions observed with the avidin-biotin-peroxidase complex technique. Cross-sections of the intraocular portion of the rat optic nerve head revealed a horizontally oval shape with distinct, vertically oriented, laminar beams. The guinea pig optic nervehead cross-section was circular, with randomly oriented beams. In both animals, collagens I, III and VI were found throughout the laminar beams, along with elastin fibrils. Collagen IV and laminin antibodies deposited along laminar beam margins and within the beams, representing astrocytic and vascular endothelial cell basement membranes. Both animals showed evidence for dermatan and chondroitin sulfate-containing proteoglycans in all connective tissue structures of the nerve head. In the rat, chondroitin-4 sulfate proteoglycans appeared localized to the sclera and laminar beams. The rat and the guinea pig optic nerve head possess an identifiable lamina cribrosa with structural proteins nearly identical to that of the primate. Both animals may provide affordable alternative animal models for in vivo studies on the role of the lamina cribrosa in glaucomatous optic nerve damage.

Animals↗
PubMed1995

fs (1) Yb is required for ovary follicle cell differentiation in Drosophila melanogaster and has genetic interactions with the Notch group of neurogenic genes.

Phenotypic and genetic analyses demonstrate that fs (1) Yb activity is required in the soma for the development of a subset of ovarian follicle cells and to support later stages of egg maturation. Mutations in fs (1) Yb cause a range of ovarian phenotypes, from the improper segregation of egg chambers to abnormal dorsal appendage formation. The mutant phenotypes associated with fs (1) Yb are very similar to the ovarian aberrations produced by temperature-sensitive alleles of Notch and Delta. Possible functional or regulatory interactions between fs (1) Yb and Notch are suggested by genetic studies. A duplication of the Notch locus partially suppresses the female-sterility caused by fs (1) Yb mutations, while reducing Notch dosage makes the fs (1) Yb mutant phenotype more severe. In addition, fs (1) Yb alleles also interact with genes that are known to act with or regulate Notch activity, including Delta, daughterless, and mastermind. However, differences between the mutant ovarian phenotype of fs (1) Yb and that of Notch or Delta indicate that the genes do not have completely overlapping functions in the ovary. We propose that fs (1) Yb acts as an ovary-specific factor that determines follicle cell fate.

Alleles↗
PubMed1995

Pentamidine aerosol versus trimethoprim-sulfamethoxazole for Pneumocystis carinii in acquired immune deficiency syndrome.

Pneumocystis carinii pneumonia remains one of the most common opportunistic infections in patients with acquired immune deficiency syndrome (AIDS). Treatment with either intravenous pentamidine or trimethoprim-sulfamethoxazole (TMP-SMX) is frequently complicated by serious adverse reactions. This study was a prospective, blinded comparison of 600 mg/d of pentamidine as an aerosol versus 15 mg/kg/d of trimethoprim plus 75 mg/kg/d of sulfamethoxazole for patients with mild or moderately severe P. carinii pneumonia (alveolar arterial oxygen difference of less than 55 mm Hg). Of 367 participants who were randomized to receive study therapies, 287 had proven and 16 had presumed Pneumocystis pneumonia. There were 29 deaths within 35 d of study initiation: 12 in the aerosolized pentamidine group and 17 in the TMP-SMX groups (log rank p = 0.28). The difference in mortality was 3.4% (95% CI = -3.5, 10.8%). Ninety-four patients treated with aerosolized pentamidine had to have their study therapy changed because of lack of efficacy, compared with 22 patients treated with TMP-SMX (p = 0.002). In addition PaO2 improved faster in patients treated with TMP-SMX. However, aerosolized pentamidine was discontinued less often than TMP-SMX because of toxicity (9.4 versus 40% p < 0.001). Rash (0.6 versus 14.9%), nausea and vomiting (1.7 versus 12.2%), and abnormalities of liver function tests (1.7 versus 12.2%) were the most common adverse effects necessitating treatment discontinuation. During 6-mo. follow-up there was no difference in mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Related Opportunistic Infections↗
PubMed1995

A congenital heart defect in Drosophila caused by an action-potential mutation.

The mutation no action potential (nap) induces arrhythmia in the heartbeat of Drosophila melanogaster larvae at temperatures above 20 degrees C; heartbeat becomes normally rhythmic again after a shift back to 20 degrees C. For this phenotype, napa is almost completely recessive to the wild type, napa also reduces the temperature-sensitivity of heart rate over a wide range of temperature, for this phenotype, napa is dominant over the wild type, napa causes reversible paralysis in adults by epistatic effects on the expression of paralyrica, a gene encoding a voltage-dependent sodium channel. However, the paramutation, which induces paralysis in adults at 29 degrees C, has no effect on larval heartbeat at temperatures between 20 degrees and 37.5 degrees C. The period gene, contra earlier reports, has no effect on heartbeat.

Action Potentials↗