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Biomedical subjects

M Hill

Publications and source records attributed to M Hill.

At least 217 records · Page 12Linked to original sources
PubMed1997

Farm worker injuries associated with bulls. New York State 1991-1996.

1. Although cows greatly outnumber bulls on dairy farms, bulls account for 25% of animal related injuries in a surveillance study of agricultural injury. In addition, bull injuries are more severe. 2. Because of their size and unpredictable behavior, bulls, especially those over 18 months of age, must be handled with extreme caution. 3. Important risk factors for the observed incidents were working alone and not having an escape route. 4. Bulls should be dehorned and confined in specially designed facilities to avoid human contact during feeding, watering, exercising, or breeding.

Accidents, Occupational↗
PubMed1997

Antisense inhibition of beta-actin mRNA localization and its effect on smooth muscle cell migration.

A crucial step in cell migration involves changes in the actin cytoskeleton in response to extracellular signals. We have previously shown that beta-actin transcripts are associated with mobile regions of mouse 3T3 fibroblasts when grown in the presence of serum. In the current study we used in situ hybridization and laser scanning confocal microscopy to show that cultured rat smooth muscle cells also localize beta-actin mRNA to the cell periphery and that this peripheral pool of beta-actin mRNA is dependent on the presence of growth factors in the culture medium. We also show that antisense phosphorothioated oligonucleotides directed against sequences in the 3' untranslated region of rat beta-actin mRNA block peripheral localization of beta-actin mRNA while the corresponding control oligonucleotides have no effect. Time-lapse video analysis demonstrates that the antisense oligonucleotides inhibit rat smooth muscle cell migration in culture and analysis of beta-actin mRNA confirms this is not due to changes in beta-actin gene expression or instability of the message. Our results suggest that depletion of beta-actin transcripts from the cell periphery is associated with suppression of SMC migration.

Actins↗
PubMed1997

Farm worker injuries associated with cows. New York State 1991-1996.

1. The size of cows and their unpredictable behavior constitute a hazard for workers who handle them. 2. When cows are startled by sudden movements and unfamiliar situations, they may kick, push, knock down, fall, or step on workers. 3. Cows in heat or those with calves are particularly excitable. Working in confining situations, such as milking stalls, exacerbates the danger of injury to handlers. 4. Knowledge of effective animal handling techniques and well designed handling facilities can reduce the incidence of injury.

Adolescent↗
PubMed1996

Phase III double-blind evaluation of an aloe vera gel as a prophylactic agent for radiation-induced skin toxicity.

PURPOSE: Considerable pilot data and clinical experience suggested that an aloe vera gel might help to prevent radiation therapy-induced dermatitis. METHODS AND MATERIALS: Two Phase III randomized trials were conducted. The first one was double blinded, utilized a placebo gel, and involved 194 women receiving breast or chest wall irradiation. The second trial randomized 108 such patients to aloe vera gel vs. no treatment. Skin dermatitis was scored weekly during both trials both by patients and by health care providers. RESULTS: Skin dermatitis scores were virtually identical on both treatment arms during both of the trials. The only toxicity from the gel was rare contact dermatitis. CONCLUSIONS: This dose and schedule of an aloe vera gel does not protect against radiation therapy-induced dermatitis.

Adult↗
PubMed1996

Concentration of the endogenous antiandrogen epitestosterone and androgenic C19-steroids in hyperplastic prostatic tissue.

Epitestosterone (epiT, 17 alpha-hydroxy-4-androsten-3-one), an endogenous C19-steroid in humans, was considered for a long time as a physiologically inactive steroid. Recently, its antiandrogenic properties have been discovered. For the evaluation of its biological availability in the target organs the tissue concentration is of importance. EpiT, testosterone, dihydrotestosterone, and androstenedione concentrations in prostatic tissue were determined in 15 prostate samples obtained by suprapubic prostatectomy for benign prostatic hyperplasia. The steroids were extracted and separated by high-pressure liquid chromatography and determined by specific radioimmunoassay (RIA) methods. The concentration of epiT (mean 58.4 +/- 40.4 SD, range 14.0-144.0 fmol/mg protein) exceeded that of testosterone and was approximately as high as that of dihydrotestosterone. EpiT level increased with age and the correlation was significant (P < 0.05). It did not correlate significantly with testosterone but did with androstenedione and dihydrotestosterone (P < 0.05, each). As expected, a positive correlation was found between testosterone and dihydrotestosterone levels.

Aged↗
PubMed1996

[Intravenous sedation of spontaneously breathing infants and small children before magnetic resonance tomography. A comparison of propofol and methohexital].

UNLABELLED: The purpose of the present study was to compare two sedation regimens with either propofol (P) or methohexital (M) for elective magnetic resonance imaging (MRI) in children with respect to safety, side effects, recovery, and discharge time. METHODS: After Institutional Review Board approval, 120 unpremedicated children with a mean age of 26.5 +/- 21.4 months (M) and 28.1 +/- 19.9 months (P) were randomly assigned to receive a hypnotic induction dose of either M or P. Supplemental bolus injections of M or P were administered to maintain adequate sedation. The following parameters were measured: heart rate, oxygen saturation by pulse oximetry (SpO2), respiratory rate, end-tidal CO2 (PetCO2), side effects, and recovery and discharge times. RESULTS: Spontaneous respiration was maintained in all patients, and ventilatory support was only necessary for 2 min in 1 M patient immediately after the induction dose. The mean loading and total doses for M were 2.3 +/- 0.7 and 6.1 +/- 3.3 mg/kg respectively, and for P 2.3 +/- 0.9 and 5.8 +/- 2.7 mg/kg. Following induction SpO2 < 90% occurred in 0.49% with M and in 0.64% with P (n.s.). Apnoe > 20s was observed in 2 children each after M and P (n.s.). The frequency of hypoventilation (PetCO2 > 48 mmHg) was 0.36% in the M group and 0.71% in the P group (n.s.). MRI sequences had to be repeated in 5% of the children in each group because of spontaneous movements. The heart rate fell significantly during MRI in both groups, while P children had lower frequencies than M children (P < 0.01). Recovery and discharge times were significantly shorter in the P group, at 0.8 min (0.08-4.8) and 2.2 min (0.2-15.0), compared to 1.5 min (0.3-28.5) and 3.5 min (0.6-40.0) in patients receiving P (P < 0.01). No patient required admission to the postanaesthesia care unit and all were free from nausea and vomiting. DISCUSSION: Intravenous sedation with M or P using the reported technique is a safe regimen for children undergoing elective MRI. The fast recovery and discharge times seem to offer advantages over general anaesthesia with endotracheal intubation. The faster recovery and discharge of only a few minutes after P compared with M is without clinical relevance.

Central Nervous System Depressants↗
PubMed1996

Prevention of recurrent atrial fibrillation with chronic dual-site right atrial pacing.

OBJECTIVES: We investigated 1) the feasibility, safety and efficacy of multisite right atrial pacing for prevention of atrial fibrillation (AF); and 2) the ability of atrial pacing in single- and dual-site modes to increase arrhythmia-free intervals in patients with drug-refractory AF. BACKGROUND: We recently developed and applied a novel technique of dual-site right atrial pacing in an unselected group of consecutive patients with AF requiring demand pacing. A prospective crossover study design was used to evaluate single- and dual-site right atrial pacing modes. METHODS: The frequency of AF during the 3 months before pacemaker implantation was analyzed. Consecutive consenting patients underwent insertion of two atrial leads and one ventricular lead with a DDDR pulse generator. Patients were placed in a dual-site pacing mode for the first 3 months and subsequently mode switched to single site pacing for 3 months. Mode switching was repeated at 6-month intervals thereafter. RESULTS: Atrial pacing resulted in a marked decline in AF recurrences (p < 0.001). During dual-site pacing with an optimal drug regimen, there was no AF recurrence in any patient compared with five recurrences in 12 patients during single-site pacing (p = 0.03). The mean (+/-SD) arrhythmia-free interval before pacing (14 +/- 14 days) was prolonged with dual- (89 +/- 7 days, p < 0.0001) and single-site pacing (76 +/- 27 days, p < 0.0001). Symptomatic AF episodes showed a declining trend during dual- and single-site pacing compared with those during the preimplantation period (p = 0.10). Mean antiarrhythmic drug use for all classes declined from 4 +/- 1.9 drugs before implantation to 1.5 +/- 0.5 (p < 0.01) drugs after implantation. Twelve (80%) of 15 patients remained in atrial paced rhythm at 13 +/- 3 months. CONCLUSIONS: We conclude that multisite right atrial pacing is feasible, effective and safe for long-term application. Atrial pacing significantly prolongs arrhythmia-free intervals in patients with drug-refractory paroxysmal AF. Dual-site right atrial pacing may offer additional benefits and should be considered either as the primary mode or in patients unresponsive to single-site pacing.

Adult↗
PubMed1996

Lack of production of the 19-kDa glycolipoprotein in certain strains of Mycobacterium tuberculosis.

The 19-kDa glycolipoprotein of Mycobacterium tuberculosis (PT19) is a prominent antigen recognized by both T cells and antibodies from tuberculosis patients. We report here that two strains, I2646 and S1, when grown either in bacteriological culture or during infection of mice, do not produce this constituent, as judged by ELISA and Western blot assays. Southern blot analysis of the chromosomal DNA showed that both strains displayed the restriction fragment as in H37Rv DNA, suggesting the lack of gross gene alterations. Sequence analysis revealed multiple microlesions including small deletions, point mutations and nucleotide insertions, leading to either premature termination or alteration of open reading frame in both strains. Transformation of both mutant strains with the wild-type gene on a multicopy plasmid resulted in overproduction of native PT19. Infection of mice suggested that the I2646 is of low virulence and that the transformant-producing native PT19 exhibited higher virulence, as assessed by viable counts and gross lesions in the infected organs. The mechanisms and significance of the lack of PT19 production in certain M. tuberculosis strains is discussed.

Animals↗
PubMed1996

High-dose chemotherapy and autologous bone marrow transplant in relapsed Hodgkin's disease--a pragmatic prognostic index.

High-dose chemotherapy with autologous bone marrow transplantation is used in the treatment of relapsed or high-risk Hodgkin's disease. As prospective randomised studies have proved difficult to accrue to, current recommendations are based on the reports of large series of prospectively collected data. We have looked at the outcome of 89 patients treated in this way at a single institution and have developed an index to predict outcome. Of 89 patients, with a median age of 29 years (range 15-51 years), eight patients were in first complete remission/partial remission (CR/PR), 17 in second or later CR, 37 were responding relapses, 13 resistant relapses, 11 primary refractory and three untested relapses. Combinations of melphalan, BCNU and etoposide were given in all cases except in ten patients who received melphalan alone. The median follow-up was 43 months (range 6-77 months). A total of 24 patients were in CR at the time of autologous bone marrow transplantation (ABMT), 33 achieved CR with ABMT, 16 PR, to give a response rate to ABMT of 49/65 = 74% (95% CI 60-83%) with a CR rate of 51% (CI 36-62%). In a Cox's multivariate analysis the most important factors in predicting outcome after ABMT were response to treatment before entry, number of previous treatments and previous chemosensitivity. Using these factors we devised a prognostic index which reliably selects a group of patients (65%) with at least a 70% chance of being progression free from 1 year onwards. Patients who have never achieved a CR and have received three or more chemotherapy regimens do not benefit from high-dose chemotherapy as used in this study.

Adolescent↗
PubMed1996

The concentrations of the endogenous C19-steroids in hyperplastic prostatic tissue and the effect of finasteride treatment.

The concentrations of the antiandrogenic endogenous steroid epitestosterone (epiT) and of testosterone, dihydrotestosterone (DHT) and androstenedione in the prostate were determined in tissue samples obtained from 21 patients who underwent suprapubic prostatectomy for benign prostatic hyperplasia. Fifteen patients received no hormonal treatment before surgery and the other 6 patients were pretreated for 8 weeks before surgery with an oral dose of 5 mg/day finasteride. The steroids were extracted and separated by high pressure liquid chromatography and determined by specific radioimmunoassays. The concentration of epiT (mean 58.4 +/- 40.4 S.D., range 14.0-144.0 fmol/mg protein) exceeded that of testosterone and was nearly as high as that of DHT. The prostatic tissue from the patients treated with finasteride for 8 weeks showed a significant decrease not only in DHT but also in androstenedione and epiT, whereas the concentration of testosterone increased significantly.

5-alpha Reductase Inhibitors↗
PubMed1996

Infected pancreatic necrosis and peripancreatic fluid collections: serendipitous response to antibiotics and medical therapy in three patients.

Three patients with clinical and radiologic evidence of pancreatic necrosis or peripancreatic fluid collections/inflammatory masses who were advised to have surgery on the basis of bacterial infection on skinny-needle aspiration of the pancreas but were deemed medically unstable or refused operative intervention were treated with intensive antibiotic therapy. All three patients survived the attack of acute pancreatitis with infection on medical therapy alone. This suggests that occasional patients with infected necrosis and/or peripancreatic collections/inflammatory masses may respond to antibiotics, especially those antibiotics that have recently been shown to have a high penetration into pancreatic tissue.

Acute Disease↗
PubMed1996

Longitudinal studies of viral sequence, viral phenotype, and immunologic parameters of human immunodeficiency virus type 1 infection in perinatally infected twins with discordant disease courses.

Perinatal human immunodeficiency virus type 1 (HIV-1) infections cause a broad spectrum of clinical disease and are variable in both the age of the patient at onset of serious disease and the progression of the clinical course. Heterozygotic perinatally infected twins with a marked difference in their clinical courses were monitored during the first 2 years of life. Twin B, the second-born twin, developed AIDS by 6 months of age and died at 22 months of age, while twin A remained minimally symptomatic through the first 2 years. Sequential blood specimens were obtained from the twins in order to characterize the immunologic properties of the children and the phenotypes and genotypes of the HIV-1 isolates at various times. Twin A developed neutralizing antibodies and a high-level antibody-mediated cellular cytotoxicity (ADCC) response, while twin B had no neutralizing antibody and a much lower ADCC response. The virus isolates obtained from the two children at various time points proliferated equally well in peripheral blood mononuclear cells, were nonsyncytium inducing, and could not infect established T-cell lines. They differed in their ability to infect primary macrophages. In parallel to the biological studies, the HIV-1 tat and part of the env gene sequences of the longitudinal isolates at four time points were determined. Sequences of virus from both twins at different time points were highly conserved; the viruses evolved at a similar rate until the last analyzed time point, at which there was a dramatic increase in sequence diversity for the sicker child, especially in the tat gene. Our results show that the viruses isolated at different times do not have significant changes in growth properties. The absence or low levels of neutralizing antibodies may correlate with disease progression in the twins.

Acquired Immunodeficiency Syndrome↗
PubMed1996

A novel technique for identification of doppler microembolic signals based on the coincidence method: in vitro and in vivo evaluation.

BACKGROUND AND PURPOSE: The applicability of a novel differentiation technique in embolus detection based on the coincidence principle and using a multigate probe was evaluated in this study. METHODS: According to the coincidence method, high-intensity transients should only be classified as microembolic signals if they appear sequentially in the two sample volumes monitored and within a defined time window calculated from the blood velocity and the spatial distance between the insonation depths. Part A: microbubbles were introduced in a continuous flow bench model of the middle cerebral artery to evaluate the accuracy of the multigate probe in embolus detection. Part B: in the subjects and patients, the minimal and maximum time delays in the appearance of microembolic signals in the two middle cerebral artery sample volumes were calculated as 0.01 second and set at 0.1 second, respectively. The multigate probe was used to monitor (1) 5 normal volunteers in whom 1008 artifact signals were produced,(2) 2 patients undergoing aortic valve replacement surgery, and (3) 12 patients with potential cardiac or carotid embolic sources. RESULTS: In the bench model, 95.5% of microembolic signals produced by microbubbles appeared in the two sample volumes with a time delay between 0.02 and 0.05 second, while in the remaining 4.5% a shorter passage time of 0.01 second was measured. A total of 1968 high-intensity signals were recorded in subjects and patients. All but 20 of these (99%) appeared in both monitoring channels within the above time frame. To summarize, 996 (98.8%) of the 1004 artifact signals and 943 (98.1%) of the 961 microembolic signals were correctly classified. CONCLUSIONS: Application of the coincidence theory to distinguish microembolic signals from artifacts provides a promising new technique with high sensitivity and specificity that could decisively improve the validity of embolus detection.

Adult↗
PubMed1996

Antirenotropic action of antiandrogens cyproterone acetate, casodex, flutamide and epitestosterone.

The antirenotropic activities of three antiandrogens which are frequently used in the clinical praxis (cyproterone acetate, flutamide and casodex) and of natural endogenous antiandrogen epitestosterone were compared. The substances were administered in oil intraperitoneally to intact male mice. The weight of kidneys was decreased most effectively by casodex and epitestosterone, though the antiandrogenic activity expressed by the decreased weight of seminal vesicles was confirmed in all preparation tested, except for flutamide. Only epitestosterone significantly reduced the level of plasma testosterone, whereas casodex increased testosterone level in plasma. LH level was decreased by testosterone propionate and epitestosterone significantly, but about 50 percent increase in the mean LH level in casodex treated animals did not reach the statistical significance.

Journal Article↗
PubMed1996

The molecular composition of neuronal microfilaments is spatially and temporally regulated.

The actin-based microfilament system is thought to play a critical role in neuronal development. We have determined specific changes in the composition of microfilaments accompanying neuronal morphogenesis. By using specific antibodies against the isoforms for tropomyosin (Tm) (Tm-5 and TmBr-1/-3) and actin (beta- and gamma-actin), we found that during early morphogenesis in vivo immature growing axons contain beta- and gamma-actin and Tm-5. In particular, Tm-5 is exclusively located in the immature axonal processes relative to the neuronal cell body. In contrast, beta-actin and Tm-5 are absent in mature, quiescent axons. This developmental loss from axons is associated with an approximately twofold downregulation of beta-actin and Tm-5 levels in the brain; gamma-actin levels do not change, and this molecule is widely distributed throughout neurons during development. The loss of beta-actin and Tm-5 from axons is accompanied by a progressive appearance of TmBr-1/-3. This apparent replacement of Tm-5 with TmBr-1/-3 occurs over a 2 d time period during rat embryonic hindbrain development and is conserved in evolution between birds and mammals. The loss of Tm-5 from axons involves a redistribution of this molecule to the cell soma and dendrites. These findings suggest that specialized microfilament domains are associated with the development and maintenance of neuronal polarity. We conclude that these Tm isoforms and beta-actin are subject to specific patterns of segregation associated with axonal development and neuronal differentiation. This provides a potential molecular basis for the temporal and spatial specificity of microfilament function during neuronal differentiation.

Actin Cytoskeleton↗
PubMed1996

Diagnosis and management of asthma: occupational health nurses' awareness and use of national consensus practice guidelines.

A regional sample of members of the American Association of Occupational Health Nurses (AAOHN) from Maryland, Delaware, Virginia, and the District of Columbia was surveyed prior to the publication of the Expert Panel Report on Guidelines for the Diagnosis and Management of Asthma (time 1). The guidelines were disseminated directly to AAOHN members through an article in AAOHN Journal and an annual convention plenary session presentation at which copies of the Report were distributed. They were disseminated indirectly through medical journals and government documents. A follow up survey of AAOHN members' familiarity with and use of the Expert Panel Report was conducted 1 year later (time 2). Of the total eligible sample of 570 persons, 325 (57.0%) responded at time 1. Of these, 232 (71.4%) responded at time 2. One year after publication, 31 (13.4%) of the nurses participating in the time 2 survey were aware of the Report, 16 (6.9%) reported having an available copy of the Report, 31 (13.4%) were familiar with the recommendations in the Report, 17 (7.3%) referred to the guidelines and 34 (14.7%) based care on the guidelines. Multiple direct dissemination strategies of consensus guidelines to improve practice will be necessary if nurses' awareness and use are to be enhanced.

Asthma↗