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Biomedical subjects

C Palmer

Publications and source records attributed to C Palmer.

At least 91 records · Page 5Linked to original sources
PubMed1995

Fetal tissue derived from spontaneous pregnancy losses is insufficient for human transplantation.

OBJECTIVE: To determine if sufficient fetal tissue with desirable transplant characteristics can be obtained from spontaneous abortions. METHODS: A survey of fetal tissues collected from newly diagnosed spontaneous pregnancy losses from three Indianapolis hospitals was conducted from December 1992 to September 1993. Forty-nine of 356 mothers (13.8%) with spontaneous abortions or ectopic pregnancies consented to the evaluation of their products of conception by gross and microscopic pathologic examination, bacterial culture, cytogenetic analysis, cell culture, and maternal serologic tests. RESULTS: Forty-nine pregnancies (gestational age range 5-30 weeks) provided four identifiable embryos, 12 second-trimester fetuses, and one third-trimester fetus. Nine samples (18.4%) were of excellent or good quality on pathologic grading. Twenty-five of 38 samples tested (66%) grew pathogenic bacteria. Maternal serologic tests were negative for antibodies to human immunodeficiency virus, human T-cell lymphotropic virus, syphilis, and hepatitis B in all cases. One of 43 sera was reactive for hepatitis C, and 33 (77%) were positive for cytomegalovirus. Cytogenetic abnormalities were found in 25% of cultured samples. Five fetal brain samples had cell viabilities of 50% or more. Few viable fetal hepatocytes were found. Only two fetal brain samples (4.1%) were potential candidates for human transplantation. CONCLUSION: Spontaneous pregnancy losses yield minimal usable tissue for human transplantation because of a lack of embryonic or fetal tissues, delayed collection, decomposition, genetic abnormality, and bacterial contamination.

Abortion, Spontaneous↗
PubMed1995

Range of planning in music performance.

Two factors influence the range of planning in music performance; the structural content of musical events and the serial distances between them. In this experiment, pianists memorized and performed polyphonic music (which contained multiple simultaneous voices) in which the serial distance and phrase structure between the entrances of 2 musical voices were varied. The distance between each musical element and its influence on other elements was assessed in production errors and interonset timing measures. Errors and timing measures offered converging evidence for interactive effects of serial distance and phrase structure; intervening phrase boundaries reduced the serial distances over which musical elements influenced one another. These findings suggest structural as well as linear constraints on the planning of complex sequences.

Adolescent↗
PubMed1994

Molecular cytogenetic determination of a deletion/duplication of 1q that results in a trisomy 18 syndrome-like phenotype.

We report on an infant who presented at birth with some characteristics of trisomy 18 syndrome, including low birth weight, facial abnormalities, overlapping fingers, and congenital heart defects. On chromosome analysis, no additional chromosome 18 was observed and both chromosome 18 homologues appeared normal. However, a small piece of chromosomal material of unknown origin was detected at the tip of the long arm of chromosome 1. Fluorescence in situ hybridization (FISH) using whole chromosome 18 painting probes disclosed no additional hybridization at the telomere of 1q, suggesting that the material was derived from another chromosome. Further chromosome painting experiments suggested that the telomeric addition was of chromosome 1 origin. To identify subchromosomal regions involved in the rearrangement, additional FISH analyses were performed using single copy and repetitive DNA probes mapping to different portions of chromosome 1. The analyses showed that probes mapping to 1q34-43 were duplicated in the derivative chromosome 1. In addition, a DNA probe mapping to 1q44 was found to be deleted from the derivative chromosome 1. Our composite analysis suggests that a deletion and a duplication of chromosome 1q can result in some of the clinical findings usually associated with trisomy 18 syndrome. These results demonstrate the usefulness of FISH analysis when karyotype analysis is not consistent with the clinical description.

Abnormalities, Multiple↗
PubMed1994

Delays in childhood immunizations in public and private settings.

BACKGROUND: As the costs of childhood immunizations have increased over the past 10 years, patients have increasingly turned to public health departments for this service. This study compares reasons for delays in immunization among patients who obtained their immunizations at health departments and those who continued to utilize private physicians or clinics. METHODS: A birth certificate survey of all children born between September 1, 1988, and August 31, 1989, in four urban census tracts and two rural counties in Kentucky was performed in late 1991, when all children were over age 2 years. The percentage of patients whose immunizations had been delayed and the reasons for delay were noted. RESULTS: Children who utilized public health departments or a combination of health departments and private sources for their immunizations were more likely to have experienced delays than those who obtained immunizations from private providers (56% vs 34%, P = .002). In particular, patients in the public provider group were more likely than those in the private provider group to have missed immunizations for invalid contraindications (34% vs 8%, P = .02), missed appointments (22% vs 9%, P = .02), or failure to receive immunizations when at the health department for another visit (23% vs 11%, P = .04). CONCLUSIONS: While a large number of patients in both the private and public provider groups experienced delays in immunizations, patients who received immunizations from public sources were more likely to experience delays related to missed opportunities.

Birth Certificates↗
PubMed1994

Deferoxamine posttreatment reduces ischemic brain injury in neonatal rats.

BACKGROUND AND PURPOSE: Iron catalyzes the formation of damaging reactive species during cerebral reperfusion. Brain iron concentration is highest at birth, so the brain of the asphyxiated newborn may be at increased risk of iron-dependent injury. We investigated whether the ferric iron chelator deferoxamine could reduce hypoxic-ischemic brain injury in neonatal rats. Because deferoxamine has concentration-dependent activities other than iron chelation, we measured brain deferoxamine levels and calculated deferoxamine pharmacokinetic parameters. METHODS: We produced hypoxic-ischemic injury to the right cerebral hemisphere of 7-day-old rats by right common carotid artery ligation followed by 2.25 hours of hypoxia in 8% oxygen. At 5 minutes of recovery from hypoxia the rats received 100 mg/kg deferoxamine mesylate or saline subcutaneously. Rats (saline, n = 33; deferoxamine, n = 38) were killed at 42 hours of recovery to assess early acute edema by measurement of hemispheric water content. Other rats (saline, n = 31; deferoxamine, n = 32) were killed at 30 days of age for morphometric determination of right hemisphere atrophy. In still other rats, we measured deferoxamine levels in blood and brain after hypoxia-ischemia. RESULTS: Deferoxamine significantly reduced right hemisphere injury as measured by early water content (P < .01) and later atrophy (P = .019). Deferoxamine brain levels peaked between 100 and 200 mumol/L at 40 to 60 minutes after injection and exceeded serum levels by +/- 70%. CONCLUSIONS: Deferoxamine administered after induction of cerebral hypoxia-ischemia reduces injury in 7-day-old rats. Deferoxamine concentrates in the brain at levels between 100 and 200 mumol/L. At the concentrations achieved, deferoxamine might protect the brain through mechanisms unrelated to its ability to chelate iron.

Animals↗
PubMed1994

Harmonic, melodic, and frequency height influences in the perception of multivoiced music.

Two experiments addressed the influences of harmonic relations, melody location, and relative frequency height on the perceptual organization of multivoiced music. In Experiment 1, listeners detected pitch changes in multivoiced piano music. Harmonically related pitch changes and those in the middle-frequency range were least noticeable. All pitch changes were noticeable in the high-frequency voice containing the melody (the most important voice), suggesting that melody can dominate harmonic relations. However, the presence of upper partials in the piano timbre used may have accounted for the harmonic effects. Experiment 2 employed pure sine tones, and replicated the effects of Experiment 1. In addition, the influence of the high-frequency melody on the noticeability of harmonically related pitches was lessened by the presence of a second melody. These findings suggest that harmonic, melodic, and relative frequency height relationships among voices interact in the perceptual organization of multivoiced music.

Acoustic Stimulation↗
PubMed1993

Units of knowledge in music performance.

The units of knowledge that form cognitive plans for music performance were examined in production errors. In Experiment 1, pianists performed multivoice homophonic music (containing strong across-voice associations) and polyphonic music (containing strong within-voice associations). Pitch errors reflected more chordal (across-voice) units in homophonic performances and more single-note units in polyphonic performances. Error instructions were harmonically and diatonically related to their intended pitches more often than chance, which demonstrates retrieval-based influences on planning. In Experiment 2, pianists conceptualized one of several voices as melody. Both the melody and the voice controlled by outer right-hand fingers (a common location of melody) contained fewer errors, which implies that there are conceptual, retrieval-based, and articulatory influences on units of knowledge that contribute to planning music performance.

Adult↗
PubMed1993

Tuberculin reactivity after neonatal percutaneous BCG immunisation.

A total of 348 neonates of Asian ethnic origin were given percutaneous BCG vaccination using a multiple puncture head. Fifty five (15.8%) were tuberculin negative when tested 6-9 weeks after vaccination, a significantly higher proportion than after intradermal vaccination. The number of abscesses after vaccination was however significantly lower.

Administration, Cutaneous↗
PubMed1993

Detection of serum antibody responses in cattle with natural or experimental Neospora infections.

Parasite-specific antibody responses were detected using an indirect fluorescent antibody (IFA) test in cattle that were naturally or experimentally infected with Neospora parasites. The test was developed using Neospora tachyzoites isolated from an aborted bovine fetus and grown in bovine cell cultures (isolate BPA1). In all cases, infections were confirmed by the identification of Neospora tachyzoites and/or bradyzoite cysts in fetal or calf tissues using an immunoperoxidase test procedure. Fifty-five naturally infected cows that aborted Neospora-infected fetuses had titers of 320-5,120 at the time of abortion. The titer of 6 cows that were serologically monitored over a prolonged period decreased to 160-640 within 150 days after they aborted infected fetuses. Two of the cows showed an increase in their Neospora titers during their subsequent pregnancy, and they gave birth to congenitally infected calves that had precolostral titers of 10,240-20,480. Postcolostral titers of these calves and of 4 other calves with congenital Neospora infections were all > or = 5,120, whereas calves with no detectable parasites had titers < or = 160. Two pregnant heifers that were experimentally infected with the BPA1 isolate at approximately 120 days gestation seroconverted to Neospora antigens within 9 days and developed peak titers of 5,120 and 20,480 within 32 days of infection. The fetus taken by caesarean section 32 days postinfection from 1 heifer and the full-term calf born to the other had Neospora titers of 640 and 10,240, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Veterinary↗
PubMed1993

Allopurinol administered after inducing hypoxia-ischemia reduces brain injury in 7-day-old rats.

We determined that treatment of immature rats with allopurinol at 15 min after cerebral hypoxia-ischemia reduces brain damage. Seven-d postnatal rats were subjected to right common carotid artery ligation followed by 2.25 h of hypoxia (8% O2). At 15 min of recovery in room air, the rat pups received either allopurinol (135 mg/kg s.c.) or saline. Some of the rats (n = 65) were killed at 42 h of recovery for measurement of cerebral hemispheric water content. Other animals (n = 63) were killed at 30 d for morphologic assessment of the severity of damage. In separate rats, we measured the levels of allopurinol and its metabolites in serum and in the brain around the time of peak serum levels. We also determined the effect of allopurinol on rat pup body temperature. Allopurinol reduced the increase in right hemisphere water content and markedly reduced atrophy. No cavitary lesions were seen in the 31 allopurinol-treated rats, whereas 15 of 32 saline-treated rats had cavitary cerebral lesions. Histologic examination confirmed that the allopurinol-treated rats had less brain injury. Serum allopurinol and oxypurinol peaked between 0.5 and 1 h after allopurinol injection. Their peak serum concentrations at 0.75 h postinjection combined was between 360 and 510 microM. Allopurinol did not lower rectal temperature more than 0.04 degrees C. In conclusion, high-dose allopurinol administered at 15 min of recovery from cerebral hypoxia-ischemia markedly reduces both acute brain edema and long-term cerebral injury in immature rats.

Allopurinol↗
PubMed1993

Potential new therapies for perinatal cerebral hypoxia-ischemia.

Recent studies in neonatal animals have shown that hypoxic-ischemic brain damage can be reduced by interventions initiated after the hypoxic-ischemic insult. In this article, the authors focus on potentially new modalities of therapy capable of preventing--or at least reducing--brain damage arising from perinatal cerebral hypoxia-ischemia. Management strategies include oxygen-free radical inhibitors and scavengers, excitatory amino acid antagonists, and calcium channel blocker. Additional information is provided regarding the critical role of glucose in perinatal cerebral hypoxia-ischemia and also the protective effect of hypothermia on preventing brain damage.

Asphyxia Neonatorum↗
PubMed1992

Allopurinol preserves cerebral energy metabolism during perinatal hypoxia-ischemia: a 31P NMR study in unanesthetized immature rats.

The effects of high dose allopurinol (ALLOP) pretreatment on the cerebral energy metabolism of unanesthetized 7-day-postnatal rats during exposure to 3 h of cerebral hypoxia-ischemia were serially quantitated using non-invasive 31P NMR spectroscopy. Adenosine triphosphate, integrated over the last 2 h of hypoxia and expressed as a fraction of baseline, was 0.73 +/- 0.16 with ALLOP pretreatment (200 mg/kg s.c.) compared to 0.52 +/- 0.05 for saline pretreatment (P = 0.001). Inorganic phosphate/phosphocreatine (Pi/PCr), integrated over the same time interval, was 2.63 +/- 1.23 relative to baseline with ALLOP versus 5.13 +/- 1.45 for saline-treated pups (P less than 0.0005). We suggest that the neuroprotection achieved with high dose ALLOP pretreatment may be attributed in part to preservation of energy metabolites.

Adenosine Triphosphate↗
PubMed1992

Growth kinetics and chemoprevention of aberrant crypts in the rat colon.

Single and multiple colonic crypts exhibiting dysplasia that are detectable in situ by staining of rat colon with methylene blue are called aberrant crypts (AC) and may serve as an intermediate marker for colon cancer. In a characterization study, we have established the kinetics of AC growth and development over a period of 20 d following injection of rats with the carcinogen azoxymethane (AOM). AC are not present at 5 d post-injection, but are a constant feature at 10 d and thereafter. Multiple AC, presumably clonal, begin to evolve at 10 d and are consistent by 20 d, forming incipient microadenomata. We have examined 20 candidate chemopreventive agents for inhibition of AC. All agents were given in AIN-76 diet, at two dose levels, with injections of AOM. AC were measured after 5 weeks of growth. Among the most active AC-inhibiting agents were BHA, DFMO, quercetin, diallyl sulfide, 18 beta-glycyrrhetinic acid, and ascorbyl palmitate. In a post-initiation study, the differentiating agent sodium butyrate was ineffective, but piroxicam was highly effective in modulating AC growth. Further, piroxicam inhibited AC development at all stages of growth from single to polycryptal clusters of AC. The AC assay shows marked sensitivity and specificity for screening agents for chemoprevention of colon cancer.

Animals↗
PubMed1992

Are we making any progress?

This report offers a limited view, by example, of dentistry's multifaceted interactions with several agencies on selected issues. It is intended to be neither comprehensive nor predictive.

American Dental Association↗