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Biomedical subjects

R S Nelson

Publications and source records attributed to R S Nelson.

At least 19 recordsLinked to original sources
PubMed2006

Exploratory laparoscopy for recurrent right lower quadrant pain in a pediatric population.

Recurrent or chronic abdominal pain can be a challenging problem when conventional diagnostic studies fail to identify the cause. It is estimated that up to one-third of children suffer from abdominal pain, and in this population recurrent pain can be even more challenging. Although recurrent right lower quadrant (RLQ) or periumbilical pain may be attributed to chronic appendicitis, this diagnosis remains controversial. Our aim was to evaluate pediatric patients who had undergone laparoscopic exploration for chronic RLQ abdominal pain to determine their histologic diagnosis, etiology of pain, and contributing factors that may predict a positive outcome. Patients with abdominal pain greater than 1 month in duration who ultimately underwent laparoscopic exploration and appendectomy were included in the study. Patients were excluded if an identified source of pain was discovered during preoperative workup, or if postoperative follow-up was less than 2 years. Intraoperative findings were noted, and all specimens were histologically examined with additional, subsequent independent review. Pertinent findings from preoperative diagnostic tests, mental health history, and pre and postoperative symptomatology were noted. Patient outcomes were recorded at the time of follow-up and after 2 years to assess resolution of their symptoms. Of the 44 patients studied, 31 (70.5%) had partial or complete resolution of symptoms at 2 years. Thirteen (29.5%) continued to have pain. Twenty-eight patients (63.6%) had abnormal histology identified on appendiceal examination, and 14 had other abnormalities found at laparoscopy (31.8%). Eighteen patients were being treated for psychiatric diagnosis, and 21 suffered from chronic headaches. There were no long-term complications from surgery. Long-term follow-up revealed that 70% reported complete or partial relief of their RLQ pain at 2 years. No factors were identified that may be helpful in predicating outcome in this population. While exploration was beneficial for a majority of this population, patients and parents should be warned that this intervention might not provide the relief of symptoms or provide the diagnostic answer to their pain.

Abdominal Pain↗
PubMed2001

Role of nitric oxide (NO) in pulmonary dysfunction associated with experimental cirrhosis.

We examined the functional role of nitric oxide (NO) and nitric oxide synthase (NOS) isoforms in the pulmonary dysfunction seen in cirrhosis. Lungs were isolated from control and carbon tetrachloride (CCl(4))-induced cirrhotic rats and perfused at constant flow with a whole blood mixture. Ventilation with hypoxic gas resulted in attenuated hypoxic pulmonary vasoconstriction (HPV) in lungs from cirrhotic animals. Administration of the non-selective NOS inhibitor N-omega-Nitro-L-Arginine (L-NNA) resulted in HPV responses that were not different between groups. However, inhibition of inducible nitric oxide synthase (iNOS) did not restore cirrhotic HPV responses. Lungs from cirrhotic rats demonstrated enhanced endothelial-dependent vasodilation to vasopressin when preconstricted with hypoxia but not when preconstricted with thromboxane mimetic. Western blot analysis failed to demonstrate differences in pulmonary endothelial NOS (eNOS) or iNOS levels between groups. Our data suggest that, while NO may play a role in mediating the reduced pulmonary vasoreactivity observed in cirrhosis, other vasoactive factors are likely also important modulators of the pulmonary dysfunction seen in this disease.

Animals↗
PubMed2001

Potato spindle tuber viroid as inducer of RNA silencing in infected tomato.

Potato spindle tuber viroid (PSTVd), an RNA plant pathogen encoding no known proteins, induces systemic symptoms on tomato plants. We report detection of small RNAs of approximately 25 nucleotides with sequence specificity to PSTVd in infected plants: an indication of the presence of RNA silencing. RNA silencing, however, did not appear to be responsible for the differing symptoms induced by a mild and a severe strain of PSTVd. The unique structural and biological features of viroids make them attractive experimental tools to investigate mechanisms of RNA silencing and pathogen counterdefense.

Gene Silencing↗
PubMed2001

West Nile virus serosurvey and assessment of personal prevention efforts in an area with intense epizootic activity: Connecticut, 2000.

West Nile virus (WNV) can cause large outbreaks of febrile illness and severe neurologic disease. This study estimates the seroprevalence of WNV infection and assesses risk perception and practices regarding potential exposures to mosquitoes of persons in an area with intense epizootics in 1999 and 2000. A serosurvey of persons aged > or = 12 years was conducted in southwestern Connecticut during October 10-15, 2000, using household-based stratified cluster sampling. Participants completed a questionnaire regarding concern for and personal measures taken with respect to WNV and provided a blood sample for WNV testing. Seven hundred thirty persons from 645 households participated. No person tested positive for WNV (95% CI: 0-0.5%). Overall, 44% of persons used mosquito repellent, 56% practiced > or = two personal precautions to avoid mosquitoes, and 61% of households did > or = two mosquito-source reduction activities. In multivariate analyses, using mosquito repellent was associated with age < 50 years, using English as the primary language in the home, being worried about WNV, being a little worried about pesticides, and finding mosquitoes frequently in the home (P<0.05). Females (OR = 2.0; CI = 1.2-2.9) and persons very worried about WNV (OR = 3.8; CI = 2.2-6.5) were more likely to practice > or = two personal precautions. Taking > or = two mosquito source reductions was associated with persons with English as the primary language (OR = 2.0; CI = 1.1-3.5) and finding a dead bird on the property (OR = 1.8; CI = 1.1-2.8). An intense epizootic can occur in an area without having a high risk for infection to humans. A better understanding of why certain people do not take personal protective measures, especially among those aged > or = 50 years and those whose primary language is not English, might be needed if educational campaigns are to prevent future WNV outbreaks.

Adolescent↗
PubMed2000

Vascular invasion routes and systemic accumulation patterns of tobacco mosaic virus in Nicotiana benthamiana.

Plant viruses must enter the host vascular system in order to invade the young growing parts of the plant rapidly. Functional entry sites into the leaf vascular system for rapid systemic infection have not been determined for any plant/virus system. Tobacco mosaic virus (TMV) entry into minor, major and transport veins from non-vascular cells of Nicotiana benthamiana in source tissue and its exit from veins in sink tissue was studied using a modified virus expressing green fluorescent protein (GFP). Using a surgical procedure that isolated specific leaf and stem tissues from complicating vascular tissues, we determined that TMV could enter minor, major or transport veins directly from non-vascular cells to produce a systemic infection. TMV first accumulated in abaxial or external phloem-associated cells in major veins and petioles of the inoculated leaf and stems below the inoculated leaf. It also initially accumulated exclusively in internal or adaxial phloem-associated cells in stems above the inoculated leaf and petioles or major veins of sink leaves. This work shows the functional equivalence of vein classes in source leaves for entry of TMV, and the lack of equivalence of vein classes in sink leaves for exit of TMV. Thus, the specialization of major veins for transport rather than loading of photoassimilates in source tissue does not preclude virus entry. During transport, the virus initially accumulates in specific vascular-associated cells, indicating that virus accumulation in this tissue is highly regulated. These findings have important implications for studies on the identification of symplasmic domains and host macromolecule vascular transport.

Plants, Toxic↗
PubMed1998

Public awareness of rabies and compliance with pet vaccination laws in Connecticut, 1993.

OBJECTIVE: To determine the degree of public awareness of rabies and compliance with cat and dog vaccination laws in Connecticut in 1993. DESIGN: Monthly telephone surveys. SAMPLE POPULATION: 1,810 households. PROCEDURE: A telephone interview was conducted, using rables-related questions contained in the Behavioral Risk Factor Surveillance System, with an adult member from households randomly selected statewide by telephone number. Results of the surveys for the year were aggregated, and weighted data were analyzed. RESULTS: Ninety percent of respondents had heard about rabies during the preceding year, and 84% considered it a problem in Connecticut. Forty-seven percent of households surveyed owned dogs or cats. Ninety-three percent of dogs and 80% of cats were reported to be vaccinated against rabies. Twenty-two percent of households with cats had at least 1 cat that was not current on rabies vaccination. CLINICAL RELEVANCE: In Connecticut, an epizootic of rabies in raccoons was accompanied by a high degree of awareness of rabies and rate of reported vaccination of dogs and cats. However, vaccination of cats was less common than that of dogs. Public education efforts should emphasize the necessity to vaccinate cats and to avoid contact with unknown cats in rabies epizootic or enzootic areas. A surveillance system can be used to help evaluate public health programs.

Adult↗
PubMed1998

Rabies prophylaxis following the feeding of a rabid pony.

A survey was performed to identify people who were exposed to a rabid pony and determine whether or not they received rabies postexposure prophylaxis (PEP). Sixty-one visitors who came in contact with the rabid pony were identified. These visitors heard about the rabid pony via the news media. Forty-five visitors were exposed during the 2 weeks before the pony died. Thirty-two of these 45 visitors received PEP. Thirty-one visitors had or may have had saliva contact to an open wound or mucosa and all 31 received PEP. Fourteen visitors had no saliva contact to a wound or mucosa and one received PEP. Sixteen visitors were exposed before the pony was potentially shedding rabies virus and one received PEP. No visitor was bitten by the pony. Most of the persons 31/33 (94%) who received PEP had an exposure for which PEP was indicated. Nonbite transmission of rabies is discussed.

Animals↗
PubMed1997

A CaMV 35S promoter driven cDNA clone of tobacco mosaic virus can infect host plant tissue despite being uninfectious when manually inoculated onto leaves.

Leading from the success of inoculating plants with viral RNA transcribed in vitro from full length cDNA clones, attempts have been made to build cDNA clones which are directly infectious by inoculation. However, we and others have found that viral cDNA clones driven by the CaMV 35S promoter were able to infect some host plants yet not others, when manually inoculated onto leaves. Alternative methods including microprojectile bombardment have been used to deliver an infectious TMV construct into plant cells resulting in the infection of all TMV host plants tested. Lack of infection via manual inoculation may be due to unsuccessful delivery of a viable construct into the plant cell nucleus.

DNA, Complementary↗
PubMed1997

Vaginal wall sling: long-term outcome analysis of factors contributing to patients satisfaction and surgical success.

PURPOSE: The clinical outcome of the vaginal wall sling was retrospectively evaluated to determine patient perception, satisfaction and factors contributing to postoperative success. MATERIAL AND METHODS: An outcome based study was conducted of 51 patients undergoing construction of a vaginal wall sling for genuine stress incontinence or intrinsic sphincteric deficiency. Preoperative symptoms, demographic parameters and video urodynamic studies were correlated with postoperative patient perception of symptoms to determine patient satisfaction and factors contributing to overall success. RESULTS: Of 42 patients (82%) available for followup 31 (74%) reported improvement in continence, 26 (62%) are currently satisfied with the urinary status, 72% in retrospect would repeat the procedure and 69% would recommended the vaginal wall sling to others. Despite long-term resolution of stress incontinence in 92% of those with genuine stress incontinence and 75% with intrinsic sphincter deficiency, postoperative urge incontinence was the single most important factor affecting patient satisfaction (p = 0.001). Patients without postoperative urge incontinence enjoyed the greatest levels of satisfaction, in excess of 90% (p = 0.001). Although preoperative leak point pressure correlated with resolution of stress incontinence, no preoperative demographic factors, symptoms or urodynamic parameters could reliably predict postoperative patients satisfaction. CONCLUSIONS: The vaginal wall sling represents an excellent option for the treatment of genuine stress incontinence and an acceptable option of intrinsic sphincteric deficiency. Patient perception and satisfaction remain closely associated with presence or resolution of postoperative urge incontinence. However, prediction of postoperative urge incontinence remains a challenge and should be considered when counseling patients preoperatively.

Aged↗
PubMed1996

Invasion of minor veins of tobacco leaves inoculated with tobacco mosaic virus mutants defective in phloem-dependent movement.

To fully understand vascular transport of plant viruses, the viral and host proteins, their structures and functions, and the specific vascular cells in which these factors function must be determined. We report here on the ability of various cDNA-derived coat protein (CP) mutants of tobacco mosaic virus (TMV) to invade vascular cells in minor veins of Nicotiana tabacum L. cv. Xanthi nn. The mutant viruses we studied, TMV CP-O, U1mCP15-17, and SNC015, respectively, encode a CP from a different tobamovirus (i.e., from odontoglossum ringspot virus) resulting in the formation of non-native capsids, a mutant CP that accumulates in aggregates but does not encapsidate the viral RNA, or no CP. TMV CP-O is impaired in phloem-dependent movement, whereas U1mCP15-17 and SNC015 do not accumulate by phloem-dependent movement. In developmentally-defined studies using immunocytochemical analyses we determined that all of these mutants invaded vascular parenchyma cells within minor veins in inoculated leaves. In addition, we determined that the CPs of TMV CP-O and U1mCP15-17 were present in companion (C) cells of minor veins in inoculated leaves, although more rarely than CP of wild-type virus. These results indicate that the movement of TMV into minor veins does not require the CP, and an encapsidation-competent CP is not required for, but may increase the efficiency of, movement into the conducting complex of the phloem (i.e., the C cell/sieve element complex). Also, a host factor(s) functions at or beyond the C cell/sieve element interface with other cells to allow efficient phloem-dependent accumulation of TMV CP-O.

Capsid↗
PubMed1996

Mapping nucleotides in the 126-kDa protein gene that control the differential symptoms induced by two strains of tobacco mosaic virus.

The differential symptom determinants of the Holmes' masked (M) and U1 strains of tobacco mosaic virus previously were mapped to the 5'-coterminal open reading frame (ORF) encoding the 126-kDa protein and the N-terminal two-thirds of the 183-kDa protein. Both proteins influence viral RNA accumulation, but the function of, and impact on, symptom formation by large domains within the 126-kDa gene, which are not conserved with sequences in analogous ORFs from other related viruses, are unknown. In the current study, cDNA clones representing each strain (i.e., MIC-TMV and U1-TMV) were mutated in these nonconserved domains to further define the nucleotides responsible for mosaic symptom induction on Nicotiana tabacum. Progeny virus of a mutant containing only eight nucleotide substitutions from the MIC-TMV sequence to the U1-TMV sequence within the 126-kDa protein ORF of MIC-TMV induced U1-TMV-like symptoms. Single or multiple substitutions among these eight nucleotides further defined residues critical for symptom modulation. Complementary substitutions in the MIC-TMV and U1-TMV sequences did not always yield progeny virus that induced complementary visual symptoms. Progeny of some mutants contained second-site spontaneous mutations at specific positions shown to influence symptom phenotype. For a subset of the stable site-directed mutants, there was no correlation between severity of systemic symptoms and chlorotic lesion size or virus accumulation in these chlorotic lesions on inoculated leaves.

Base Sequence↗
PubMed1996

'Abnormal' diastolic Doppler patterns in patients over age 65 with severe left ventricular systolic dysfunction.

OBJECTIVE: The purpose of this study was to determine whether Doppler diastolic filling patterns of the left ventricle are altered in patients over age 65 with poor left ventricular function, compared to patients with normal left ventricular systolic function. BACKGROUND: In elderly, healthy subjects, the mitral valve Doppler inflow pattern exhibits an increase in atrial contribution to left ventricular filling. Myocardial disease, which results in stiffness, may also cause an increase in A wave velocity. METHODS: Twenty-seven patients over age 65, with left ventricular systolic dysfunction, were age and sex-matched with 19 patients with normal left ventricular systolic function. Patients with significant mitral or aortic valvular disease were excluded. Maximal early inflow velocity, maximal atrial inflow velocity, heart rate, acceleration time and deceleration time were calculated. RESULTS: Comparing the group with normal left ventricular systolic function, the group with decreased left ventricular systolic function had pseudonormalization of the maximal early flow/atrial flow velocity ratio (1.7 +/- 1.3 vs. 0.9 +/- 0.3; P = 0.003), E wave velocity was similar (82 +/- 28 vs. 70 +/- 24 cm/s; P = n.s.), and A wave velocity was diminished (66 +/- 30 vs. 84 +/- 20 cm/s; P = 0.02). The acceleration time was similar for the groups (53 +/- 17 vs. 46 +/- 21 ms), but the deceleration time was shorter in patients with left ventricular systolic dysfunction (122 +/- 33 vs. 192 +/- 80 ms; P < 0.001). CONCLUSION: Such differences may relate to increased left atrial pressure, increased left ventricular diastolic pressure and/or decreased atrial systolic function. These findings are important when interpreting left ventricular filling indices by Doppler echocardiography in elderly patients.

Aged↗
PubMed1996

Prostatic carcinoma with abundant xanthomatous cytoplasm. Foamy gland carcinoma.

Foamy gland carcinoma, an unusual variant of prostate carcinoma, is characterized by abundant xanthomatous cytoplasm. We studied 38 needle biopsies in which at least one core contained cancer with >20% foamy morphology. On average, each cancer was 72% foamy, and 11 cancers were entirely foamy. In addition to the characteristic cytoplasm, 20 cases had abundant intraluminal dense pink amorphous secretions. Nuclear enlargement and prominent nucleoli were either absent of rare in 23 (61%) and 27 (71%) of foamy gland carcinomas, respectively. High-molecular-weight cyto-keratin stains were done in 20 cases; 19 foamy gland carcinomas were negative, confirming the diagnosis of carcinoma and one case had keratin staining inconsistent with a known benign pattern. Of the 27 cases with associated ordinary gland carcinoma on needle biopsy, 26 (96%) were Gleason sum greater than 4. Subsequent radical prostatectomy (RP) and transurethral resection demonstrating cancer were available in 17 cases. Of the 15 subsequent RPs, only five were organ-confined and only one was Gleason sum less than 5. The cancers in the RP group ranged from 1 to 90% foamy (mean, 39%). Foamy gland carcinoma must be recognized as carcinoma by its abundant foamy cytoplasm, its architectural pattern of crowded or infiltrative glands, and frequently present pink acellular secretions. The more typical features of adenocarcinoma, nuclear enlargement and prominent nucleoli, are frequently absent. Its relatively benign cytology makes this lesion difficult to recognize as carcinoma; 74% of our cases were seen in consultation. Despite its benign cytology, foamy gland carcinoma is best classified as intermediate-grade carcinoma.

Adenocarcinoma↗
PubMed1996

The 126- and 183-kilodalton proteins of tobacco mosaic virus, and not their common nucleotide sequence, control mosaic symptom formation in tobacco.

Nucleotide substitutions at two positions within the open reading frame encoding the 126-kDa protein in the attenuated masked (M) strain of tobacco mosaic tobamovirus (TMV) to those found in the virulent U1-TMV genome led to the induction of near U1-TMV-like symptoms on leaves of Nicotiana tabacum L. cv. Xanthi nn by progeny virus (M. H. Shintaku, S. A. Carter, Y. Bao, and R. S. Nelson, Virology 221:218-225, 1996). In this study, further site-directed mutations were made at these positions within the M strain cDNA to determine whether the protein or nucleotide sequence directly controlled the symptom phenotype. The protein and not the nucleotide sequence directly controlled the symptom phenotype when amino acid 360 within the 126-kDa protein sequence was altered and likely controlled the symptom phenotype when amino acid 601 was altered. The effects of the substitutions at amino acid position 360 on viral protein accumulation were studied by pulse-labeling proteins in infected protoplasts. Accumulation of the 126- and 183-kDa proteins was less for an attenuated mutant than for two virulent mutants, but the viral movement protein and coat protein accumulated to levels reported to be sufficient for normal systemic symptom development. The size of necrotic local lesions on N. tabacum L. cv. Xanthi NN was negatively correlated with symptom development and accumulation of the 126-kDa protein for these mutants. With reference to this last finding, an explanation of the cause of the differing symptoms induced by these viruses is presented.

Amino Acid Sequence↗
PubMed1996

Enhanced cytochemical detection of viral proteins and RNAs using double-sided labeling and light microscopy.

We have developed a double-sided labeling technique for detecting viral proteins or RNAs in plastic-embedded leaf tissue by immunocytochemistry or in situ hybridization, respectively, and light microscopy. The signal from the target was enhanced by double-sided labeling when compared with single-sided labeling because sections were submerged in labeling solutions with both sides accessible to antibodies or complementary RNAs. The additional label was visible during microscopic analysis. Background signal was decreased since the tissue was probed and washed under conditions where folds and creases in the tissue were minimized. This technique uses the same equipment and chemicals as for single-sided labeling, and thus adjustments for reagent expenditures are not necessary. The procedure should be applicable to animal and plant tissue.

Animals↗
PubMed1995

Is esthesioneuroblastoma a peripheral neuroectodermal tumor?

Esthesioneuroblastoma (ENB; olfactory neuroblastoma) is a rare, locally aggressive neoplasm of the sinonasal area and anterior cranial fossa. The histogenesis of the lesion is not clearly delineated, and the broad histological spectrum of ENB has confounded the issue. The location, histological features (neuropil, Homer Wright, and olfactory rosettes), and reported immunocytochemical reactions (neuron-specific enolase (NSE) and chromogranin (CHR) positivity) suggest that ENB may be a neural or neuroendocrine neoplasm derived from the olfactory membrane. Recent demonstration in two of three metastatic putative ENB cell lines of the 11;22 chromosomal translocation, seen in Ewing's sarcoma (ES) of bone and peripheral neuroectodermal tumors (PNET) of bone and soft tissue, has led to the conclusion that ENB may be closely related histogenetically to PNET. The overwhelming majority of cases of ES and PNET express the protein product of MIC-2, a gene located on the pseudoautosomal region of the X and Y chromosomes. This protein can be identified immunocytochemically by antibodies 12E7, HBA71, and ON13. We studied the expression of MIC-2 using the 12E7 antibody as well as multiple neural markers in 18 ENB samples obtained from the files of The Johns Hopkins Hospital. The patients ranged in age from 19 to 90 years (mean, 47.5; median, 47) and included five men and 13 women. None of the 18 specimens reacted with antibody 12E7, but 16 were positive for NSE, nine reacted to synaptophysin (SYN), and 13 showed antibodies to chromogranin (CHR). Our studies agree with the previous suggestions that ENB is a primitive neural tumor but fail to support the hypothesis that it is a member of the PNET family.

12E7 Antigen↗