Biomedical subjects
C Tucker
Publications and source records attributed to C Tucker.
Patient information. Finding local heroes.
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Developmental analysis of the cytomegalovirus enhancer in transgenic animals.
The major immediate-early promoter (MIEP) of human, cytomegalovirus (HCMV) constitutes a primary genetic switch for viral activation. In this study, regulation of the enhancer-containing segment (nucleotides -670 to +54) of the HCMV MIEP attached to the 1acZ reporter gene was examined in the developing embryos of transgenic mice to identify temporal and tissue-specific expression. We find that the transgene reporter is first detected as a dorsal stripe of expression in the neural folds of embryos at day 8.5 postcoitum (p.c.). A broad expression pattern is exhibited in embryos at day 9.5 p.c. This pattern becomes more restricted by day 10.5 p.c. as organogenesis progresses. By day 14.5 p.c., prominent expression is observed in a subpopulation of central nervous system cells and spinal ganglia, endothelial cells, muscle, skin, thyroid, parathyroid, kidney, lung, liver, and gut cells, and the pancreas and submandibular and pituitary glands. This distribution pattern is discussed in relation to human congenital HCMV infection. These results suggest that the transcriptional activity of the HCMV MIEP may determine in part, the ability of the virus to specifically target developing fetal tissues in utero.
Superior gluteal artery perforator free flap for breast reconstruction.
The purpose of this paper is to present a new method of breast reconstruction utilizing skin and fat from the buttock without muscle sacrifice. Cadaver dissections were done to study the musculocutaneous perforators of the superior gluteal artery and vein. Eleven breasts were reconstructed successfully with skin/fat flaps based on the superior gluteal artery with its proximal perforators. Long flap vascular pedicles allow the internal mammary or thoracodorsal vessels to be used as recipient vessels. This new technique has several advantages over the previously described gluteus maximus myocutaneous flaps, including long vascular pedicle and no muscle sacrifice.
Developing a community for patients with sickle cell anemia at Harbor-UCLA.
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Effectiveness of the ivermectin sustained-release bolus in the control of bovine nematodosis.
OBJECTIVE: To evaluate the nematocidal effectiveness of the ivermectin sustained-release bolus throughout its 135-day delivery period. DESIGN: Twenty-four naturally infected calves were randomly allocated to 1 of 3 equivalent experimental groups: group-T1 calves were untreated controls, group-T2 calves each received a sustained-release bolus on trial day 0, and group-T3 calves were rendered nematode-free and used at 35-day intervals during the study as tracers. One contaminated pasture was used for all principal calves for the 135-day grazing interval of the study. Calves of groups T1 and T2 were also artificially administered mixed infective nematode larvae at intervals during the grazing period, after which, all calves were confined to concrete for 21 days prior to necropsy. ANIMALS: All calves were approximately 6 months old on trial day 0, weighed from 136 to 216 kg, and were of mixed breeding and sex. PROCEDURE: At intervals during the study, feces from all calves were analyzed for nematode egg counts, and all calves were weighed and examined for bolus retention (T2 calves only). For nematode recovery, all calves were necropsied 21 to 22 days after removal from the contaminated pasture. RESULTS: Parasitic populations of Haemonchus, Ostertagia, Trichostrongylus, Cooperia, Bunostomum, and Oesophagostomum spp were significantly reduced in cattle treated with the ivermectin sustained-release bolus. CONCLUSION: The nematocidal activity of the ivermectin sustained-release bolus proved highly effective, with > 98% efficacy for all nematode species present.
Efficacy of doramectin against naturally acquired gastrointestinal nematode infections in cattle.
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Residual anthelmintic activity of abamectin in artificially infected calves.
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Effectiveness of doramectin for treatment of experimentally induced gastrointestinal tract larval nematode infections in calves.
Anthelmintic efficacy of doramectin, a macrocyclic lactone of the avermectin family, was evaluated against larval parasitic nematodes in calves. The investigational product was given SC at a dosage of 0.2 mg/kg of body weight to 10 calves infected 6 days previously with third-stage larvae of the genera Haemonchus, Ostertagia, Cooperia, and Nematodirus. Ten additional calves with identical larval exposure were given saline solution SC also at 6 days after inoculation, and served as the nonmedicated controls. At 14 or 15 days after treatment, the calves were slaughtered in complete replicate for nematode recovery and subsequent quantifications. In comparing nematode numbers at necropsy for the saline- and doramectin-treated groups, nematocidal effectiveness as directed against fourth-stage larvae was: 100% for Haemonchus placei and Cooperia spp, > 99% for Ostertagia ostertagi, and 64.5% for Nematodirus helvetianus. All treatments were easily administered, and adverse behavioral or tissue reactions were not seen to result from doramectin administration.
Residual nematocidal effectiveness of ivermectin in cattle.
We assessed the duration of ivermectin persistence by measuring posttreatment nematocidal effectiveness; topical and injectable formulations of ivermectin were evaluated. Thirty-five nematode-free calves were randomly allocated to 1 of 5 treatment groups (7 calves/group). The treatment (Trt) group designations were: Trt 1, nonmedicated; Trt 2, injectable ivermectin administered at the rate of 0.2 mg/kg of body weight on day 0; Trt 3, injectable ivermectin administered at the aforementioned rate, but on day 7; Trt 4, topically administered ivermectin at the rate of 0.5 mg/kg on day 0; and Trt 5, topically administered ivermectin at the aforementioned rate, but on day 7. All calves were subsequently given infective larvae of Haemonchus, Cooperia, Trichostrongylus, and Oesophagostomum spp on day 21. One week later, each calf was additionally administered infective larvae of Dictyocaulus and Ostertagia spp. Trial calves were euthanatized on trial days 49 to 52 for nematode quantitation. On the basis of geometric mean comparisons, total nematode burdens were reduced from control group counts by 98.9 and 86.3% for calves treated on days 7 and 0 with injectable formulations, respectively, and 97.2 and 64.7% for calves treated on days 7 and 0 with pour-on formulations, respectively. Trichostrongylus colubriformis infections were most refractory to the persistent activity of ivermectin, with H placei also proving to be persistence limiting. All treatments were easily administered, and adverse behavioral or tissue reactions were not observed.
Chemical recognition of kingsnakes by crotalines: effects of size on the ophiophage defensive response.
When confronted by an ophiophagous (snake-eating) kingsnake, venomous snakes of the subfamily Crotalinae exhibit a suite of defensive responses including head hiding, thrashing, and an unusual response termed 'body bridging'. Other responses observed, such as biting and 'freezing', are more general in nature and can occur in a variety of contexts. Various crotalines of differing sizes were tested for their responses to kingsnakes (Lampropeltis getulus). Responses of individuals were recorded for up to 18 months. The results indicate that, if habituation can be overcome by periodically allowing a kingsnake to confront but not harm the crotaline, the response is dependent on the size of the crotaline, in that smaller specimens (< 0.9 m) respond readily, while larger snakes (> 1.0 m) tend not to respond. The size of the kingsnake apparently does not have an effect on the crotaline response. These data appear to resolve apparent conflicts in the literature regarding whether certain species respond to ophidian ophiophages. In addition, hexane extracts of kingsnake skin were fractionated using an alumina column. The various fractions obtained were tested to determine which elicited the defensive response. Activity was found only in the most non-polar fraction. Preliminary analysis by gas chromatography/mass spectrometry indicated that this fraction contained straight and branched, saturated and polyunsaturated long-chain hydrocarbons.
Biological significance of cell cycle kinetics in 128 standard risk newly diagnosed patients with acute myelocytic leukemia.
Bromodeoxyuridine (BrdU) was administered to 128 newly diagnosed patients with standard risk acute myelocytic leukaemia (AML) for cell cycle measurements. Labelling indices (LI) were obtained from both the bone marrow aspirate (BMasp) and biopsies (bx) and durations of S-phase (Ts) and total cell cycle time (Tc) were measured by double-labelling the S-phase cells in vitro with tritiated thymidine. Median LI BMasp was 8% and from BMbx was 25%. The median Ts was 12 h (range 3.1-35 h) and Tc was 48 h (range 11.5-211 h). All patients received induction therapy with a combination of cytosine arabinoside and an anthracycline. Outcome of therapy or FAB type were not related to cell cycle characteristics. Patients with above median LI BMasp, however, had longer remission durations (P = 0.03) as did patients with above median Ts (P = 0.03) and Tc (P = 0.03). Upon longer follow-ups, even some of the patients with slowly cycling myeloblasts have relapsed (log rank P = 0.453 and 0.203 for Ts and Tc respectively). We conclude that patients with rapidly cycling cells tend to relapse faster; however, slowly cycling nature of myeloblasts is not associated with curability.
Acute pain and substance abuse in surgical patients.
Studies have determined that nurses and physicians undermedicate patients for postoperative pain as a result of inadequate knowledge and erroneous attitudes. Fear of addiction seems to be the major reason for this undertreatment. A patient who abuses drugs requires larger than usual doses of narcotics postoperatively; however, larger doses are rarely given. This article emphasizes factors influencing the postoperative pain experience and presents 3 case studies to illustrate pain management in patients who abuse substances.
Turf issues in CMHCs.
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Giant esophageal fibrolipoma: case report and review of the literature.
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The use of written simulations and trained patients to evaluate a course in rheumatology.
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Safety assessment for the postictal confusional phase following complex partial seizure.
Misunderstanding of the postictal confusional state that follows the complex partial seizure has caused emotional and physical harm to patients. Concern about this phenomenon and its effects upon the patient prompted this study to explore, describe, and document one method of intervention to lessen these harmful effects. An evaluative descriptive research design was employed to assess patient safety during and after the postictal confusional phase following a complex partial seizure. A closed-structured questionnaire and participant observation were the methods used to collect data for this study. A Level of Safety Tool was specifically designed for this study.
A new method for assessing right-sided heart pressures using encapsulated microbubbles--a preliminary report.
A new noncatheter method for measuring pressures of the right side of the heart uses specially manufactured microbubbles of carbon dioxide injected into the peripheral venous system. Sudden expansion of these bubbles in the cardiac chambers causes bubble oscillations at a frequency that is primarily a function of surrounding pressure. The oscillations are recordable by a microphone on the chest wall. The preliminary experience has been in dogs and further development is needed before we can begin clinical testing of the method. In its current form, the potential for measuring higher systolic pressures seems better than that for lower diastolic pressures.