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D M Harris

Publications and source records attributed to D M Harris.

At least 37 records · Page 2Linked to original sources
PubMed1994

A hospital study of ice-making machines: their bacteriology, design, usage and upkeep.

Ice-making machines have occasionally been implicated in nosocomial infection. We have examined the ice-making machines in our hospital both bacteriologically and for their general state of cleanliness and repair. Results were variable but, in most cases few organisms of significance were found. Some design features are considered and recommendations for the purchase, maintenance, cleaning and use of these machines are included.

Cross Infection↗
PubMed1993

Effect of in vivo somatotropin treatment of growing pigs on adipose tissue lipogenesis.

The present study was undertaken to determine the effects of porcine somatotropin (pST) on glucose flux rates, lipogenic enzyme activities, and the abundance of fatty acid synthase mRNA in pig adipose tissue. Barrows were injected daily with 120 micrograms of pST/kg BW (n = 6) or excipient (n = 6). On d 11 of treatment, pigs were slaughtered (empty BW = 77 +/- 2 kg) and subcutaneous adipose tissue was collected. Basal incorporation of [14C]glucose into total lipid decreased by 86% with pST treatment, whereas glucose oxidation to CO2 decreased by 79%. Insulin (10 ng/mL) stimulated both glucose oxidation and incorporation into lipid by a small increment of similar magnitude for both treatment groups. Rates of lipogenesis determined in vitro were highly correlated with similar measurements made in vivo on the same set of animals (r = .76). The reduction in basal rates of lipogenesis corresponded to a 79% decrease in total (activated) acetyl-coenzyme A carboxylase activity and a 67% decrease in fatty acid synthase activity. Reduced nicotinamide adenine dinucleotide phosphate-generating enzymes were decreased to a lesser extent. Northern blot analysis of RNA from the same animals reveal a 90% decrease in mRNA for fatty acid synthase in the pST-treated group. The correlation between mRNA abundance and enzyme activity for fatty acid synthase was .90. These data indicate that the pST-induced reduction in adipose tissue lipid accretion in growing barrows is largely a result of diminished rates of lipogenesis that are manifestations of the decreased activities of the fatty acid-synthesizing enzymes. These changes seem to result from suppression of genes that encode for the lipogenic enzymes.

Acetyl-CoA Carboxylase↗
PubMed1993

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Antitrust Laws↗
PubMed1992

Effect of somatotropin on nonesterified fatty acid and glycerol metabolism in growing pigs.

Eight crossbred barrows (71 kg initial BW) were allocated to two treatments involving daily i.m. injections of either excipient (control) or recombinantly derived porcine somatotropin (120 micrograms/kg of BW). On d 8 of treatment, beginning 15 h after injection, glycerol and nonesterified fatty acid (NEFA) kinetics were determined using a primed, continuous infusion of [2-3H]glycerol and [9,10(n)-3H]oleic acid. Kinetics were examined under both basal conditions and during a hyperinsulinemic/euglycemic clamp. Plasma concentrations of NEFA and glycerol and their respective entry rates were highly correlated. Insulin had no effect on plasma glycerol or glycerol entry rate, probably due to the very low rates that were observed in both the control and somatotropin-treated pigs. However, both plasma NEFA and oleic acid entry rate were reduced during hyperinsulinemia. Although indices of fat mobilization tended to be higher in pigs treated with somatotropin, the magnitude of the increases were small and would be sufficient to account for only a minor fraction of the decreased lipid accretion observed in somatotropin-treated pigs.

Animals↗
PubMed1992

Effect of porcine somatotropin on in vivo glucose kinetics and lipogenesis in growing pigs.

Crossbred barrows were used for in vivo studies investigating hormonal regulation of lipogenesis. The first experiment examined an in vivo method for determining rates of lipogenesis. Three barrows were infused with [U-14C]glucose and incorporation of radioactivity into triglycerides was determined in up to five biopsies of subcutaneous adipose tissue obtained over 7 h. Incorporation was linear after blood glucose specific radioactivity had reached a plateau and was constant over the entire infusion. For the second experiment, eight pigs (71 +/- 2.5 kg) were allocated to one of two treatments involving daily injections of excipient (control) or porcine somatotropin (pST; 120 micrograms/kg of BW). On d 10, beginning 15 h after injection, glucose incorporation into adipose tissue lipid was determined under both basal and hyperinsulinemic/euglycemic conditions. Basal glucose incorporation into lipid, particularly fatty acids, was markedly reduced (greater than 90%) during pST treatment. Although glucose incorporation was increased to a similar extent in both groups by hyperinsulinemia, the pST-treated pigs still exhibited markedly lower rates. Based on kinetic data, the decrease in lipid accretion of pST-treated pigs was primarily the result of a decrease in the rate of de novo synthesis. Furthermore, the reductions in glucose incorporation into fatty acids, glucose irreversible loss rate, and feed intake that occur with pST treatment were quantitatively similar.

Adipose Tissue↗
PubMed1991

Photodynamic therapy for corneal neovascularization.

We have previously described corneal neovascularization (CNV) induced by the intrastromal injection of interleukin-2 (IL-2) in inbred mice. Photodynamic therapy (PDT), administered by a deeply penetrating 630 nm fiberoptic laser, can destroy neoplasms and their associated neovascularization with some selectivity, but can damage neighboring tissues when used for CNV. We performed PDT with a 514 nm ophthalmic argon laser in an attempt to induce regression of CNV and reduce the associated toxicity. Eight weeks following IL-2 injection, mice with CNV were injected i.v. with dihematoporphyrin ether (DHE). Seventy-two hours later, 11 eyes (group I) were irradiated with eight 800 mW, 1000 mu, 2 s spots. Controls included 11 vascularized corneas from mice that received DHE but no laser (group II), 11 that received laser but no DHE (group III), and 35 untreated vascularized corneas (group IV). Comparison of the mean areas of CNV in groups I through IV pretreatment (6.0, 6.5, 6.7, and 7.6 mm2) and 12 weeks posttreatment (4.3, 6.3, 5.6, and 7.5 mm2) revealed that a significant decrease was seen in group I only (p less than 0.04, ANOVA). Complications in group I included blepharitis (9%) and iris damage (18%). Histologic studies revealed no evidence of posterior segment damage. PDT with the 514 nm laser is safe and efficacious for the treatment of IL-2-induced CNV in this model.

Analysis of Variance↗
PubMed1990

Prophylaxis against hepatitis A for travel.

OBJECTIVE: To develop a rational practice policy for prophylaxis against hepatitis A for travellers to high risk areas. DESIGN: 18 Month prospective study of consecutive patients who requested prophylaxis against hepatitis A. SETTING: Inner city general practice. SUBJECTS: 104 Patients aged 15-61 (mean 30) assessed for risk factors for hepatitis A and put into groups depending on predictions from the risk factors of their immunity. MAIN OUTCOME MEASURES AND RESULTS: All patients were screened for antibody to hepatitis A virus. Of 52 patients with no risk factors 47 had no antibody and were thus susceptible to hepatitis A. All 27 patients with major risk factors (having been brought up in an endemic area or with a history of jaundice) were immune. Of 25 patients with minor risk factors (a history of previous travel in high risk areas, drug abuse, having lived in a squat or travelled rough, or having lived with someone who had jaundice) 12 were immune (p less than 0.001, chi 2 test). CONCLUSIONS: All travellers requesting prophylaxis against hepatitis A should be assessed for risk factors for previous exposure to hepatitis A. Those with no risk factors could be immunised with human normal immunoglobulin without screening. The remainder should be tested for hepatitis A antibody and those found to be susceptible should be immunised.

Adolescent↗
PubMed1990

Photodynamic therapy in the treatment of squamous cell carcinoma of the head and neck.

Photodynamic therapy is an experimental modality for tumor treatment based on the combined action of the tumor-localizing agent, ie, hematoporphyrin derivative, and red light. From 1985 through 1989, 26 patients were treated using hematoporphyrin-derived drugs and 630-nm light delivered by a tunable dye laser. All patients had biopsy-proved squamous cell carcinoma of the head and neck, and they had either failed the traditional treatment modalities or refused conventional therapies. Histological complete responses were achieved in 20 (77%) of 26 patients and partial responses in 5 (19%) of 26 patients for periods up to 48 months. Only minimal toxic reaction was noted in the group. As a guide to treatment planning for a patient group with large tumors, we used an optical dosimetry model based on tissue optics. The rate of complete responses to this treatment was 8 (73%) of 11. Our data indicate that photodynamic therapy is capable of inducing significant clinical and histological responses in the majority of those treated, and in some patients a prolonged response is produced. In certain select head and neck malignancies, photodynamic therapy has an important role as a treatment modality.

Aged↗
PubMed1990

Postnatal growth of cochlear spiral in Mongolian gerbil.

Measurements were made of cochlear dimensions in an age-graded series of Mongolian gerbils. The radii of the cochlear spiral at five locations and the length of the modiolus were determined from in situ photographs of mid-modiolar sections. The anterior to posterior dimensions of the auditory bulla and of the inferior colliculus were also measured to provide a general context for inner ear growth functions. At birth in this species, the cochlear capsule is still growing, and, although the basal turn is closer to the final adult proportion than more apical turns, all radii approach adult dimensions together at 9-10 days after birth (DAB). Comparison of the morphological development of gerbil otic capsule with the change in cochlear tonotopic mapping observed during physiological development shows that growth is complete before the onset of measurable electrical responses at 12-14 DAB.

Animals↗
PubMed1988

Single-dose efficacy and safety of zindotrine, a new oral bronchodilator.

Zindotrine, a new bronchodilator, may be an alternative to theophylline in treating reversible airflow obstruction. Efficacy and cardiovascular effects of a single 300 mg oral dose of zindotrine were compared with placebo in a two-period, double-blind, crossover trial. Twelve subjects with airflow obstruction reversible after isoproterenol and theophylline completed the trial. Improvement in pulmonary function (forced vital capacity [FVC], forced expiratory volume in one second, and forced expiratory flow rate from 25 to 75 percent of FVC) was greater after zindotrine than with placebo. Pulmonary function tests increased 15 percent or more over baseline in 30 minutes after active drug, lasting up to 6 hours. Mild decreases in heart rate and mean blood pressure occurred after both treatments, with changes equal in both treatment groups. Six subjects had mild subjective side effects after zindotrine (headache, dizziness, vertigo, flushing, and heartburn) compared with one report of lightheadedness after placebo. A single dose of zindotrine 300 mg provides effective bronchodilator action with a relatively prolonged response and tolerable side effects.

Adult↗
PubMed1988

Autologous fibrin tissue adhesive: factors influencing bonding power.

Bonding power of Autologous Fibrin Tissue Adhesive (AFTA) is directly related to its fibrinogen concentration. By increasing the ammonium sulfate concentration 100% during fibrinogen precipitation, the bonding power of two glued 1-cm2 pieces of human dura almost doubled. No relationship between blood fibrinogen level and bonding power was demonstrated. Comparing AFTA with Fibrin Sealant, the commercial fibrin tissue adhesive, shearing strength between two glued pieces of human dura with AFTA was less 10 minutes and greater 30 minutes after gluing. Gluing a TORP (Richards) to a 1-cm2 piece of human dura yielded generally somewhat greater bonding power when using Fibrin Sealant. Autologous Fibrin Tissue Adhesive provides bonding power adequate for middle-ear surgery, eliminates transmission of viral diseases and, unlike Fibrin Sealant, AFTA is available in the United States.

Ammonium Sulfate↗
PubMed1988

Effects of caffeine and 3-isobutyl 1-methyl xanthine on caprine milk secretion.

The objective of these studies was to determine if methyl xanthines can be used to alter milk production or composition in ruminants by enhancing adipose tissue mobilization. Three trials were conducted, one with intravenous caffeine infusions, one with intramuscular caffeine injections, and one with intramuscular injections of 3-isobutyl 1-methyl xanthine. Results indicate that: 1) continuous intravenous infusions of caffeine (720 mg/d) may reverse the milk fat depression of intravenously infused glucose in dairy goats; 2) intramuscular injections of caffeine (200 mg twice daily) do not reverse the milk fat-depressing effects of pelleted dairy goat diets during the 4th mo of lactation; and 3) intramuscular injections of 3-isobutyl 1-methyl xanthine (50 mg twice daily) do not consistently affect milk production of early lactation dairy goats.

1-Methyl-3-isobutylxanthine↗
PubMed1987

Endogenous porphyrin fluorescence in tumors.

The fluorescence of endogenous porphyrins in tumors has been attributed to the presence of several different species of bacteria inhabiting ulcerated and necrotic tissues. We have examined this "autofluorescence" in carcinogen-induced tumors in the hamster oral mucosa and in patients with cancer of the oral cavity. In several instances, bright autofluorescence of normal tissues has been observed. This represents a potential false-positive identification of cancer when systemic hematoporphyrin derivative fluorescence is used as a diagnostic technique.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1987

Current source density analysis of frequency coding in the inferior colliculus.

Current source density (CSD) analysis is a technique that provides information about the time course and spatial location of transmembrane currents derived from a laminar collection of evoked potentials. Restrictive conditions for acquisition of evoked potentials are required in order to yield a one-dimensional CSD analysis that is an accurate estimate of synaptic activity. Satisfaction of these conditions was assumed in recordings of tone-burst-evoked potentials along the axis of symmetry (tonotopic) in the inferior colliculus of adult mongolian gerbils. Off-line these data were converted into distance/voltage functions. The second spatial derivatives of these functions gave a family of profiles of the spatial distribution of current source and sink densities at discrete latencies relative to the stimulus. Results indicate a frequency-dependent spatial shift in the evoked current sink of about 280 microns octave. This sink, indicative of local excitatory synaptic drive, is surrounded, both spatially and temporally, by current sources. The spatial extent of excitation as estimated from CSD analysis, compares well quantitatively with predictions from an across-neuron model that is based on single unit data.

Acoustic Stimulation↗
PubMed1987

Corneal neovascularization. Pathogenesis and inhibition.

Corneal neovascularization (CNV) can cause significant visual loss because of the scarring and lipid deposition that frequently accompany it. In addition, penetrating keratoplasty in a vascularized recipient carries a significant risk of failure from allograft rejection. Frequently CNV is induced by nonspecific inflammatory stimuli, mediated primarily by polymorphonuclear neutrophils. Neovascularization can also be associated with specific corneal immune reactions, such as herpes simplex keratitis. Immunologically mediated CNV may be more amenable to treatment than CNV that results from nonspecific inflammation. Photodynamic therapy (PDT) following the intravenous injection of hematoporphyrin derivative or purified dihematoporphyrin ether (DHE) has been shown to suppress tumor growth and blood vessel growth in the eye. We have developed a murine model of CNV induced by the intrastromal injection of stimulated lymphocytes or interleukin-2 (IL-2). We have noted corneal DHE retention following its intravenous injection in mice with IL-2 induced CNV. Preliminary studies indicate that PDT can induce regression of CNV in these mice. Other recent studies that have enhanced our understanding of the pathogenesis and treatment of CNV are reviewed, and directions for future research are discussed.

Animals↗