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L Davis

Publications and source records attributed to L Davis.

At least 37 records · Page 2Linked to original sources

Effect of Withania somnifera on CTL activity.

The stimulatory effect of Withania somnifera on cytotoxic T lymphocytes was determined in Balb/C mice by the Winn's Neutralization assay using CTL sensitive EL4 thymoma cells as target cells. Withania somnifera showed a significant increase in CTL production both in vivo as well as in vitro. The survival time of E14 cells alone in treated animals was only 21 days and in the Withania extract treated group was 45 days with a percentage increase in life span (% ILS) of 114.28%. The survival rate of animals administered with EL4 cells (target) which were incubated with alloimmunized spleen cells (effector) from normal Balb/c mice was 33 days (% ILS 57.14%) and when this group was treated with Withania extract (20 mg/dose/animal i.p. for 10 days) their life span was increased to 53 days (% ILS 152.38%). The survival days of animals after the administration of EL4 cells incubated with alloimmunized spleen cells (effector) from Withania treated animals was 48 days (% ILS 118.18%) and when these animals continued with the Withania treatment their life span increased to 61 days (%ILS 177.27%). There was a significant increase in life span when animals were treated with EL4 cells incubated with effector cells generated by mixed lymphocyte culture of Balb/c mice and C57BL/6 mice in the presence (172.73%) and absence of Withania extract (59.09%). These studies indicate that Withania somnifera could stimulate the generation of cytotoxic T lymphocyte and it may reduce tumour growth.

Animals↗

Effect of Withania somnifera on cell mediated immune responses in mice.

Effect of Withania somnifera on the cellular immune responses (CMI) was studied in normal as well as tumour bearing animals. Administration of Withania extract was found to enhance the proliferation of lymphocytes, bone marrow cells and thymocytes in responses to mitogens. Both PHA and Con A mitogens along with Withania treated splenocytes, bone marrow cells and thymocytes could stimulate proliferation twice greater than the normal. Withania treated splenocytes along with the mitogen LPS (10 microg/ml) could stimulate the lymphocyte proliferation six times more than the normal. Natural killer cell activity (NK) was found to be enhanced significantly in both the normal and the tumour bearing group and it was found to be earlier than the control (48.92% cell lysis). Antibody dependent cellular cytotoxicity (ADCC) was found to be enhanced in the Withania treated group on the 9th day (65% cell lysis). An early Antibody dependent complement mediated cytotoxicity (ACC) was observed in the Withania treated group on day 13 (47% cell lysis).

Animals↗

Molecular polymorphism of the intermediate filament protein transitin.

Transitin is an avian intermediate filament protein whose transient expression in the progenitor cells of the muscle and nerve tissues is similar to that of mammalian nestin. Both proteins contain an alpha-helical core domain flanked by a short N-terminal head and a long C-terminal extremity. However, the tail region of transitin is significantly different from that of nestin in that it harbors a unique motif containing more than 50 leucine zipper-like heptad repeats which is not found in any other intermediate filament protein. Despite the absence of introns in this region of the transitin gene, it was reported that different isoforms of the protein were produced by exclusion or inclusion of a number of repeats generated by an unusual splicing mechanism recognizing consensus 5' and 3' splice sites contained within the coding sequence of the heptad repeat domain [Napier et al. (1999) J Mol Neurosci 12:11-22]. Two monoclonal antibodies (mAbs) reacting with repeated epitopes of this motif were used to monitor transitin expression during in vitro myogenesis of the quail myogenic cell line QM7. Confocal microscopy revealed that the subcellular domains decorated with mAbs A2B11 and VAP-5 were mutually exclusive: the intermediate filament network visualized with mAb VAP-5 appeared to abut on a submembranous domain defined by mAb A2B11. When QM7 cells were induced to differentiate by switching to medium containing low serum components, an early effect was the local loss of A2B11 cortical staining at the points of cell-cell contacts. The A2B11 signal also disappeared before that of VAP-5 in newly formed myotubes. Unexpectedly, the mutually exclusive staining pattern of the mAbs could not be explained by alternative splicing since both epitopes mapped to a repeated element preceding the consensus 5' splice sites of the heptad repeat domain. An alternative explanation would be that the central repeat domain of transitin is a polymorphic structure from which different conformations exist depending on the local context. This hypothesis is strengthened by the observation that in cultured neural crest cells, the A2B11 antigen is preferentially expressed by freely migrating crest cells whose intracellular pH and calcium concentrations are different from those of non-migrating cells.

Amino Acid Sequence↗

Meiotic recombination and chromosome segregation in Schizosaccharomyces pombe.

In most organisms homologous recombination is vital for the proper segregation of chromosomes during meiosis, the formation of haploid sex cells from diploid precursors. This review compares meiotic recombination and chromosome segregation in the fission yeast Schizosaccharomyces pombe and the distantly related budding yeast Saccharomyces cerevisiae, two especially tractable microorganisms. Certain features, such as the occurrence of DNA breaks associated with recombination, appear similar, suggesting that these features may be common in eukaryotes. Other features, such as the role of these breaks and the ability of chromosomes to segregate faithfully in the absence of recombination, appear different, suggesting multiple solutions to the problems faced in meiosis.

Animals↗

Interferon-alpha and ribavirin for the treatment of recurrent hepatitis C after liver transplantation.

BACKGROUND: Initial studies utilizing interferon-alpha and ribavirin for the treatment of recurrent hepatitis C virus (HCV) infection after liver transplantation showed promising results. Here we report our single-center experience using this combination therapy. METHODS: Liver transplant recipients with recurrent HCV (elevated serum aminotransferases, positive serum HCV RNA, and biopsy-proven hepatitis without rejection) received interferon-alpha (1.5-3 million units subcutaneously three times a week) and ribavirin (400-1000 mg p.o. daily) for 12 months or more. Serum aminotransferases, HCV RNA, and severity of hepatitis were followed. RESULTS: Thirty-two patients have been treated for at least 3 months, including 13 who have been on 12 or more months of therapy. Three died from allograft failure due to recurrent HCV. Dose reductions of interferon-alpha and/or ribavirin occurred in 22 patients. Thirteen had their medications permanently discontinued for severe adverse effects. Twenty-six patients (81%) had a biochemical response (BR; normalization of serum aminotransferases) after 3 months. End-of-treatment and sustained BR were 77% and 71%, respectively. Mean viral loads decreased 68-77%; however, only three patients became serum HCV RNA negative. After 12 months of therapy, no histological improvement was observed in 11 patients who were biopsied. Patients who received mycophenolate mofetil or daclizumab had a less likelihood of achieving a BR. CONCLUSIONS: A significant number of patients did not tolerate interferon-alpha or ribavirin. Although BR was excellent and mean viral loads decreased significantly, virological clearance was poor and no histological improvement was noted. A more efficacious treatment with less adverse effects for recurrent HCV after liver transplantation is needed.

Adult↗

Surveillance of work-related carpal tunnel syndrome in Massachusetts, 1992-1997: a report from the Massachusetts Sentinel Event Notification System for Occupational Risks (SENSOR).

BACKGROUND: This surveillance study was undertaken to target efforts to prevent work-related carpal tunnel syndrome (WR-CTS) and to assess physician case-reports as a source of surveillance data. METHODS: Physician case-reports and workers' compensation disability claims were used to document patterns of WR-CTS in Massachusetts from March 1992 to June 1997 by age, gender, industry, occupation, and calendar year. Characteristics of cases identified through the two data sources were compared. RESULTS: 4,836 cases of WR-CTS were ascertained; 6% were identified by both data sources. Whereas the two sets of cases were similar with respect to age and occupation categories, physician-reported cases were more likely male and employed in manufacturing. The number of compensation claims filed by women declined over time, and a substantial number of cases under age 25 years were identified. Manufacturing workers had the highest rates; the highest numbers of cases were employed in hospitals, grocery stores, and the insurance industry. Several technical/administrative support occupations likely to use video display terminals had both high rates and frequencies. CONCLUSION: WR-CTS is a significant public health problem. Physician reports are useful in understanding problem magnitude and targeting specific establishments for intervention but are currently of limited use in targeting specific industries and occupations.

Administrative Personnel↗

Availability and quality of industry and occupation information in the Massachusetts Cancer Registry.

BACKGROUND: Industry and occupation (I/O) data from state cancer registries can be useful in generating and evaluating hypotheses about occupational cancer risks. The quality of these data is uncertain. METHODS: We reviewed medical records on 1,020 cases from the Massachusetts Cancer Registry (MCR). We compared the presence and detail of I/O data from this dedicated record review (DRR) with routine reporting to the MCR in order to evaluate the potential to increase the availability of I/O data. RESULTS: Compared to routine reporting, the DRR increased the percentage of codable I/O data from 63.6 to 80.4%. The DRR also provided more detail in existing codes in 15.4% of cases. Other sections of the medical record in addition to the face sheet and sections of the record from the period before cancer diagnosis were important sources of additional information. Duration and timing of the corresponding I/O information were rarely recorded. CONCLUSIONS: The nearly one-third (32%) of records that had some improvement in I/O information with a dedicated review indicates considerable opportunity to improve the utility of this resource.

Adolescent↗

Validity of a telephone-administered 24-hour dietary recall in telephone and non-telephone households in the rural Lower Mississippi Delta region.

OBJECTIVE: To determine if 24-hour dietary recall data are influenced by whether data are collected by telephone or face-to-face interviews in telephone and non-telephone households. DESIGN: Dual sampling frame of telephone and non-telephone households. In telephone households, participants completed a 24-hour dietary recall either by face-to-face interview or telephone interview. In non-telephone households, participants completed a 24-hour dietary recall either by face-to-face interview or by using a cellular telephone provided by a field interviewer. SUBJECTS/SETTING: Four hundred nine participants from the rural Delta region of Arkansas, Louisiana, and Mississippi. MAIN OUTCOME MEASURES: Mean energy and protein intakes. STATISTICAL ANALYSES PERFORMED: Comparison of telephone and non-telephone households, controlling for type of interview, and comparison of telephone and face-to-face interviews in each household type using unpaired t tests and linear regression, adjusting for gender, age, and body mass index. RESULTS: Mean differences between telephone and face-to-face interviews for telephone households were -171 kcal (P = 0.1) and -6.9 g protein (P = 0.2), and for non-telephone households -143 kcal (P = 0.6) and 0.4 g protein (P = 1.0). Mean differences between telephone and non-telephone households for telephone interviews were 0 kcal (P = 1.0) and -0.9 g protein (P = 0.9), and for face-to-face interviews 28 kcal (P = 0.9) and 6.4 g protein (P = 0.5). Findings persisted when adjusted for gender, age, and body mass index. No statistically significant differences were detected for mean energy or protein intake between telephone and face-to-face interviews or between telephone and non-telephone households. APPLICATIONS/CONCLUSIONS: These data provide support that telephone surveys adequately describe energy and protein intakes for a rural, low-income population.

Adolescent↗

Effect of Withania somnifera on DMBA induced carcinogenesis.

Administration of an extract of Withania somnifera was found to reduce two stage skin carcinogenesis induced by DMBA (dimethyl benzanthracene) and croton oil. Withania somnifera was administered at a concentration of (20 mg/dose/animal i.p.) consecutively on 5 days prior to DMBA administration and continued twice weekly for 10 weeks. After the 180th day of carcinogen administration, all of the animals developed papilloma in the control group whereas only six out of 12 animals developed papilloma in the treated group. A total of 11 papillomas were found in the control group while only six developed them in the Withania somnifera treated group. Enzyme analysis of skin and liver showed significant enhancement in antioxidant enzymes such as GSH, GST, Glutathione peroxides and Catalases in Withania somnifera treated group when compared with the control. The elevated level of lipid peroxide in the control group was significantly inhibited by Withania somnifera administration. These studies indicate that Withania somnifera could reduce the papilloma induced alterations to the antioxidant defense systems.

9,10-Dimethyl-1,2-benzanthracene↗

Evidence that hospital hygiene is important in the control of methicillin-resistant Staphylococcus aureus.

Observational and microbiological data were collected from the patients and environment of a male general surgical ward over a period of 27 months from January 1998. Isolates of methicillin-resistant Staphylococcus aureus (MRSA) from patients and environment were typed by antibiogram, bacteriophage and pulsed field gel electrophoresis of chromosomal DNA. In September 1999, an intervention was put in place which included increasing the domestic cleaning time by 57 hours per week, with emphasis on removal of dust by vacuum cleaning, and allocation of responsibility for the routine cleaning of shared medical equipment. From January 1998 to September 1999, despite standard infection control measures (emphasis on hand hygiene, isolation of affected patients and staggered closure and cleaning of ward bays), 69 patients acquired a strain of E-MRSA16. This strain was also widespread in the ward environment. Typing confirmed that isolates from patients and environment were indistinguishable from one another and that the outbreak was due to a single strain. This strain was responsible for postoperative infection in approximately one third of the patients who acquired it. In the six months following the intervention, only three patients were colonized with the outbreak MRSA and monthly surveys failed to detect this strain in the environment. Thorough and continuous attention to ward hygiene and removal of dust was needed, to terminate a prolonged outbreak of MRSA infection on a general surgical ward, in addition to standard infection control measures. Control of hospital-acquired infection with MRSA requires a combination of measures, none of which are completely effective in isolation.

Cost-Benefit Analysis↗

The Saccharomyces cerevisiae MUM2 gene interacts with the DNA replication machinery and is required for meiotic levels of double strand breaks.

The Saccharomyces cerevisiae MUM2 gene is essential for meiotic, but not mitotic, DNA replication and thus sporulation. Genetic interactions between MUM2 and a component of the origin recognition complex and polymerase alpha-primase suggest that MUM2 influences the function of the DNA replication machinery. Early meiotic gene expression is induced to a much greater extent in mum2 cells than in meiotic cells treated with the DNA synthesis inhibitor hydroxyurea. This result indicates that the mum2 meiotic arrest is downstream of the arrest induced by hydroxyurea and suggests that DNA synthesis is initiated in the mutant. Genetic analyses indicate that the recombination that occurs in mum2 mutants is dependent on the normal recombination machinery and on synaptonemal complex components and therefore is not a consequence of lesions created by incompletely replicated DNA. Both meiotic ectopic and allelic recombination are similarly reduced in the mum2 mutant, and the levels are consistent with the levels of meiosis-specific DSBs that are generated. Cytological analyses of mum2 mutants show that chromosome pairing and synapsis occur, although at reduced levels compared to wild type. Given the near-wild-type levels of meiotic gene expression, pairing, and synapsis, we suggest that the reduction in DNA replication is directly responsible for the reduced level of DSBs and meiotic recombination.

Alleles↗

Characterization of ocular surface symptoms from optometric practices in North America.

PURPOSE: This study characterized ocular symptoms typical of dry eye in an unselected optometric clinical population in the United States and Canada. METHODS: Self-administered dry eye questionnaires, one for non-contact lens wearers (dry eye questionnaire) and one for contact lens wearers (contact lens dry eye questionnaire), were completed at six clinical sites in North America. Both questionnaires included categoric scales to measure the prevalence, frequency, diurnal severity, and intrusiveness of nine ocular surface symptoms. The questionnaires also asked how much these ocular symptoms affected daily activities and contained questions about computer use, medications, and allergies. The examining doctors, who were masked to questionnaire responses, recorded a nondirected dry eye diagnosis for each patient, based on their own diagnostic criteria. RESULTS: The dry eye questionnaires were completed by 1,054 patients. The most common ocular symptom was discomfort, with 64% of non--contact lens wearers and 79% of contact lens wearers reporting the symptom at least infrequently. There was a diurnal increase in the intensity of many symptoms, with symptoms such as discomfort, dryness, and visual changes reported to be more intense in the evening. The 22% percent of non-contact lens wearers and 15% of contact lens wearers diagnosed with dry eye (most in the mild to moderate categories) reported symptoms at a greater frequency than those not diagnosed with dry eye. CONCLUSIONS: Our results show that symptoms of ocular irritation and visual disturbances were relatively common in this unselected clinical population. The intensity of many ocular symptoms increased late in the day, which suggested that environmental factors played a role in the etiology of the symptoms.

Activities of Daily Living↗

Foreign matter salpingitis 3 years after typhlitis.

This case suggests that typhlitis may cause delayed abdominal pathology. A history of this condition should be considered in the work-up of any patient with gastrointestinal or genitourinary pathology.

Abdomen, Acute↗

Peroxisome proliferator-activated receptor-gamma activity is associated with renal microvasculature.

Peroxisome proliferator-activated receptor-gamma (PPAR gamma) is a nuclear transcription factor and the pharmacological target for antidiabetic thiazolidinediones (TZDs). TZDs ameliorate diabetic nephropathy and have direct effects on cultured mesangial cells (MCs); however, in situ hybridization failed to detect expression of PPAR gamma in glomeruli in vivo. The purpose of this study was to determine whether PPAR gamma is expressed in renal glomeruli. Two rabbit PPAR gamma isoforms were cloned. Nuclease protection assays demonstrate that both PPAR gamma isoforms are expressed in freshly isolated glomeruli. Treatment of rabbits with the TZD troglitazone selectively induced expression of an endogenous PPAR gamma target gene, adipocyte fatty acid-binding protein (A-FABP), in renal glomerular cells and renal medullary microvascular endothelial cells, demonstrated by both in situ hybridization and immunostain. Troglitazone also dramatically increased A-FABP expression in cultured MCs. Constitutive PPAR gamma expression was detected in cultured rabbit MCs. Endogenous MC PPAR gamma can also drive PPAR gamma reporter. Troglitazone and 15-deoxy-Delta 12,14 prostaglandin J(2) at low concentrations reduced mesangial cell [(3)H]thymidine incorporation without affecting viability. These data suggest that constitutive PPAR gamma activity exists in renal glomeruli in vivo and could provide a pharmacological target to directly modulate glomerular injury.

Amino Acid Sequence↗

Urogenital distribution of a mouse membrane-associated prostaglandin E(2) synthase.

PGE(2) plays a critical role in regulating renal function and facilitating reproduction. One of the rate-limiting biosynthetic enzymes in PGE(2) synthesis is the terminal PGE(2) synthase (PGES). In the present studies, we report the functional expression of a membrane-associated murine PGES (mPGES) and its expression in urogenital tissues. Two independent cDNA clones sharing an identical open reading frame of 459 bp and encoding a peptide of 153 amino acids, but differing in the 3'-untranslated region, were identified. Assays for enzymatic activity, using microsomes prepared from cells transfected with mPGES cDNA, showed that these cDNA sequences encode a functional protein that catalyzes the conversion of PGH(2) to PGE(2). Constitutive expression of mPGES was highest in the mouse kidney, ovary, and urinary bladder but was also expressed at lower levels in uterus and testis. Renal mPGES expression was predominantly localized to epithelia of distal tubules and medullary collecting ducts. High expression was also seen in transitional epithelial cells of bladder and ureter and in the primary and secondary follicles in the ovary. In conclusion, mPGES is constitutively expressed along the urogenital tract, where it may have important roles in normal physiology and disease.

Amino Acid Sequence↗