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Biomedical subjects

N Lowe

Publications and source records attributed to N Lowe.

At least 37 records · Page 2Linked to original sources
PubMed1995

Mini-slit graft hair transplantation using the Ultrapulse carbon dioxide laser handpiece.

BACKGROUND: The new Ultrapulse carbon dioxide (CO2) laser technology has added a new dimension to many cosmetic surgery procedures including hair transplantation. Early reports by Unger and David (Laser Hair Transplantation. J Dermatol Surg Oncol 1994;20:515-21) have been encouraging with the potential of minimal bleeding, ease of placing transplanted grafts, and an overall shortened operative time. A 2-mm slit handpiece has been recently created to expedite this procedure. OBJECTIVE: The purpose of this study is to further investigate the use and efficiency of the new Ultrapulse CO2 laser slit handpiece in hair transplants. METHOD: Mini-slit graft hair transplants using the new Ultrapulse CO2 laser slit handpiece were done on 25 patients in 30 transplant sessions. Donor minigrafts were obtained by the strip harvesting technique using a triple-blade scalpel. Approximately 200-400 recipient slits were made with the 2-mm slit handpiece at the laser setting of 350 mJ, 12 W, 0.8 seconds per pulse. RESULTS: All grafts were easily placed into recipient sites with minimal bleeding and charring. The procedure was done in half the time of the conventional non-laser technique. Postoperatively, patients were quite satisfied with little pain and swelling. Histologic exams of the laser-treated slits showed minimal adjacent tissue necrosis. Long-term follow-up visits showed good regrowth of hair in these grafts. CONCLUSION: The new Ultrapulse CO2 laser slit handpiece proved to be an effective tool for mini-slit graft hair transplantation.

Adult↗
PubMed1994

Neural net-bootstrap hybrid methods for prediction of complications in patients implanted with artificial heart valves.

A novel hybrid methodology for prediction of valve related complications in patients with implanted artificial heart valves is discussed. Artificial neural networks provided a mechanism for prediction of postoperative valve-related deaths based on preoperative patient information and valve parameters. Then bootstrap methodology was applied for estimating prediction errors and maximizing prediction accuracy. Data from a clinical trial with 10 years of follow-up on 789 patients implanted with Carpentier-Edwards Pericardial Bioprosthesis were used. A random subset of the data was reserved for validation of the final outcome. The remaining patients' records were repeatedly divided into two groups, using resampling strategy provided by the bootstrap methodology. One of the groups was used for training the neural net and the other one for testing the trained network and determining error rates. Patient information, such as sex, age, NYHA class and anticoagulation therapy, as well as valve parameters, such as size and the date of implant were used as the network inputs. Calculated error rates were then used for assessing the distribution of the error, further optimization of the neural network, and constructing confidence intervals for the error rates. Thus, reliable statistical estimation was obtained on the prediction accuracy. Additionally this new hybrid methodology allowed us to optimize the neural network even further, raising the accuracy of prediction to 78%.

Bioprosthesis↗
PubMed1992

Interaction of ethanol with beta-carotene: delayed blood clearance and enhanced hepatotoxicity.

Because we had found that ethanol interacts with retinol, we investigated whether it also affects its precursor, beta-carotene. In 14 baboons fed ethanol (50% of total energy) for 2 to 5 yr with a standard amount of beta-carotene (one 200-gm carrot/day), levels of beta-carotene were much higher than in controls fed isocaloric carbohydrate, both in plasma (122.5 +/- 30.9 nmol/dl vs. 6.3 +/- 1.4 nmol/dl; p less than 0.005) and in liver (7.9 +/- 1.1 nmol/gm vs. 1.8 +/- 0.5 nmol/gm; p less than 0.001). Even 20 days after withdrawal of the carrots, plasma beta-carotene levels remained higher in alcohol-fed baboons than in controls (10.1 +/- 3.8 nmol/dl vs. less than 0.1 nmol/dl). Next, the diet was supplemented with beta-carotene beadlets: in four pairs of baboons given a low dose of beta-carotene (3 mg/1,000 kcal), plasma levels were significantly higher in alcohol-fed animals than in controls, even when expressed per cholesterol (although the latter increased with alcohol intake). Seven pairs of animals were given a higher dose (30 mg/1,000 kcal) of beta-carotene for 1 mo, followed, in four pairs, by 45 mg for another month. On cessation of beta-carotene treatment, plasma levels decreased more slowly in the alcohol-fed baboons than in the controls. Percutaneous liver biopsy specimens revealed that liver concentrations of beta-carotene correlated with plasma levels but were higher in the alcohol-fed baboons than in the control baboons, whereas the beta-carotene-induced increase in liver retinoids was lower (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Efficacy of a 1-week, twice-daily regimen of terbinafine 1% cream in the treatment of interdigital tinea pedis. Results of placebo-controlled, double-blind, multicenter trials.

BACKGROUND: Patients with tinea pedis often discontinue treatment before eradication of the fungus when their symptoms improve. The result is an incomplete cure/recurrence. OBJECTIVE: Terbinafine, a topical fungicidal agent, was evaluated in double-blind, placebo-controlled trials (159 patients) for its ability to achieve cure and relief of symptoms in the same time frame, that is, before compliance wanes. METHODS: Mycologic characteristics (with potassium hydroxide examination and culture) and clinical signs and symptoms were assessed at baseline, at the end of a 1-week, twice-daily treatment and at 1, 3, and 5 weeks after the completion of therapy. RESULTS: Both terbinafine and vehicle provided early relief of symptoms. However, only terbinafine gave progressive mycologic improvement such that at 5 weeks after treatment, 88% of the patients receiving terbinafine had converted from positive to negative mycology compared with 23% of the patients treated with vehicle. CONCLUSION: The rapid and potent fungicidal action of terbinafine results in a high cure rate in interdigital tinea pedis with 1 week of treatment and may avoid failures caused by non-compliance.

Antifungal Agents↗
PubMed1992

The effect of intralesional 5-fluorouracil therapeutic implant (MPI 5003) for treatment of basal cell carcinoma.

BACKGROUND: Basal cell carcinomas (BCCs) are usually treated with ablative procedures. A nonsurgical treatment alternative would be of value in selected patients. OBJECTIVE: We evaluated the safety and efficacy of a new preparation for intralesional sustained-release chemotherapy with MPI 5003, 5-Fluorouracil Therapeutic Implant, for treatment of BCCs. METHODS: Two doses of intralesional MPI 5003 (0.25 and 0.5 ml) were compared in a double-blind study of 20 patients with biopsy-proven BCC. One BCC per patient was treated weekly for up to 6 weeks and followed up monthly for 3 months until excisional biopsy for histologic examination. Before excision the cosmetic appearance of the test site was graded. RESULTS: Eighty percent of 10 BCCs treated with 0.5 ml of MPI 5003 had histologically confirmed cures as compared with 60% of 10 tumors treated with the lower dose (0.25 ml). Cosmetic assessments before excision were typically good to excellent. No systemic side effects occurred. CONCLUSION: Results indicate the potential of MPI 5003 for targeted local chemotherapy for BCC.

Adult↗
PubMed1992

Carbonic anhydrase 3 (CA3), a mesodermal marker.

Carbonic anhydrase 3 (CA3) is an abundant muscle protein characteristic of adult type 1, slow-twitch, fibres. The protein plays an important role in facilitated CO2 diffusion and diverse processes involving H+ and HCO-3 transport. Nucleotide sequence comparisons have identified putative promoter and enhancer regions in the 5' flanking sequences of the CA3 gene. Functional assays show that 2.8kb of 5' flanking sequence efficiently promotes transcription of a reporter gene in a muscle specific manner. Removal of sequences 5' to -722bp leads to a major loss of activity and this result implies that the proximal promoter region which includes a GArG box and four potential MyoD1 binding sites is not adequate for maximal transcription. The longest CA3 promoter construct is also active in 10T1/2 cells, which are precursor mesodermal cells and do not normally express CA3. In situ hybridization to mRNA in developing mouse embryos reveals a pattern of expression in myotomes and pre-muscles masses of the limb buds which is consistent with the regulation of CA3 by myogenic determination factors. These studies also showed that CA3 expression is not confined to cells of the muscle lineage since it is expressed in primitive mesoderm prior to the onset of myogenesis. Later in embryogenesis CA3 defines a subset of mesodermal cell types which includes not only skeletal muscle but also notochord and adipocytes.

Animals↗
PubMed1991

The human carbonic anhydrase I gene has two promoters with different tissue specificities.

Primer extension and S1 nuclease analysis of human carbonic anhydrase I (HCA1) mRNA transcripts in erythroid and non-erythroid tissues show that the HCA1 gene has two promoters with different tissue specificities, separated by 36 kb of DNA. The promoter of the HCA1 gene which is active in non-erythroid tissue shows strong sequence similarity with a similar region in the mouse CA1 gene, but has two equally used transcription start sites.

Animals↗
PubMed1991

Physical mapping of the human carbonic anhydrase gene cluster on chromosome 8.

A cluster of genes encoding the three cytoplasmic carbonic anhydrase isozymes CAI, CAII, and CAIII lie on the long arm of chromosome 8 (8q22) in humans. These genes have been mapped using pulsed-field gel electrophoresis. The genes lie in the order CA2, CA3, CA1. CA2 and CA3 are separated by 20 kb and are transcribed in the same direction, away from CA1. CA1 is separated from CA3 by over 80 kb and is transcribed in the direction opposite to CA2 and CA3. The arrangement of the genes is consistent with proposals that the duplication event which gave rise to CA1 predated the duplication which gave rise to CA2 and CA3. The order of these three genes differs from that suggested for the mouse based on recombination frequency.

Blotting, Southern↗
PubMed1990

A clinical trial of beta carotene to prevent basal-cell and squamous-cell cancers of the skin. The Skin Cancer Prevention Study Group.

BACKGROUND: Beta carotene has been associated with a decreased risk of human cancer in many studies employing dietary questionnaires or blood measurements, and it has had protective effects in some animal models of carcinogenesis. METHODS: We tested the possible cancer-preventing effects of beta carotene by randomly assigning 1805 patients who had had a recent nonmelanoma skin cancer to receive either 50 mg of beta carotene or placebo per day and by conducting annual skin examinations to determine the occurrence of new nonmelanoma skin cancer. RESULTS: Adherence to the prescribed treatment was good, and after one year the actively treated group's median plasma beta carotene level (3021 nmol per liter) was much higher than that of the control group (354 nmol per liter). After five years of follow-up, however, there was no difference between the groups in the rate of occurrence of the first new nonmelanoma skin cancer (relative rate, 1.05; 95 percent confidence interval, 0.91 to 1.22). In subgroup analyses, active treatment showed no efficacy either in the patients whose initial plasma beta carotene level was in the lowest quartile or in those who currently smoked. There was also no significant difference between treated and control groups in the mean number of new nonmelanoma skin cancers per patient-year. CONCLUSIONS: In persons with a previous nonmelanoma skin cancer, treatment with beta carotene does not reduce the occurrence of new skin cancers over a five-year period of treatment and observation.

Aged↗
PubMed1990

Structure and methylation patterns of the gene encoding human carbonic anhydrase I.

The gene (CAI) encoding human carbonic anhydrase I (CAI) has been isolated and shown to have a total length of 50 kb. Some 36 kb of this consists of a large intron separating the erythroid-specific promoter from the coding region. A small (54 bp) noncoding exon from within this intron is occasionally found in transcripts. Two different polyadenylation sites have been found, the most distal of which is the most commonly used. Methylation levels near the promoter differ widely in cell lines. In CAI-expressing cells, a region of DNA near the promoter is demethylated in a generally highly methylated background. Surprisingly, non-CAI-expressing cell lines show much lower levels of methylation.

Amino Acid Sequence↗
PubMed1990

S-adenosyl-L-methionine attenuates alcohol-induced liver injury in the baboon.

Chronic ethanol consumption by baboons (50% of energy from a liquid diet) for 18 to 36 mo resulted in significant depletion of hepatic S-adenosyl-L-methionine concentration: 74.6 +/- 2.4 nmol/gm vs. 108.9 +/- 8.2 nmol/gm liver in controls (p less than 0.005). The depletion was corrected with S-adenosyl-L-methionine (0.4 mg/kcal) administration (102.1 +/- 15.4 nmol/gm after S-adenosyl-L-methionine-ethanol, with 121.4 +/- 11.9 nmol/gm in controls). Ethanol also induced a depletion of glutathione (2.63 +/- 0.13 mumol/gm after ethanol vs. 4.87 +/- 0.36 mumol/gm in controls) that was attenuated by S-adenosyl-L-methionine (3.89 +/- 0.51 mumol/gm in S-adenosyl-L-methionine-methanol vs. 5.22 +/- 0.53 mumol/gm in S-adenosyl-L-methionine controls). There was a significant correlation between hepatic S-adenosyl-L-methionine and glutathione level (r = 0.497; p less than 0.01). After the baboons received ethanol, we observed the expected increase in circulating levels of the mitochondrial enzyme glutamic dehydrogenase: 95.1 +/- 21.4 IU/L vs. 13.4 +/- 1.8 IU/L; p less than 0.001, whereas in a corresponding group of animals given S-adenosyl-L-methionine with ethanol, the values were only 30.3 +/- 7.1 IU/L (vs. 9.6 +/- 0.7 IU/L in the S-adenosyl-L-methionine controls). This attenuation by S-adenosyl-L-methionine of the ethanol-induced increase in plasma glutamic dehydrogenase (p less than 0.005) was associated with a decrease in the number of giant mitochondria (assessed in percutaneous liver biopsy specimens), with a corresponding change in the activity of succinate dehydrogenase, a mitochondrial marker enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine Transaminase↗
PubMed1990

Fluosol and oxygen breathing as an adjuvant to radiation therapy in the treatment of locally advanced non-small cell carcinoma of the lung: results of a phase I/II study.

Fluosol, a perfluorcarbon emulsion, has the ability to carry oxygen in solution. In conjunction with oxygen breathing and radiation, Fluosol has been shown in animal models to enhance local tumor control. In September 1985, a Phase I/II Study was instituted to evaluate the effect of this adjuvant therapy with radiation in non small cell carcinoma of the luing. Fifty patients were enrolled in the study which was closed for accrual in November 1987. Five patients were withdrawn prior to the institution of radiation: one patient diagnosed with bone metastasis and four patients withdrawn due to mild to moderate reactions to Fluosol. Of the 49 patients administered Fluosol, 34 mild to moderate adverse reactions were noted in 22 patients to either the test dose/infusion (16 reactions including withdrawn patients) or post infusion (18). Flushing, dyspnea and hypertension (test dose/infusion) and chills and/or fever (postinfusion) were the typical symptoms. Transient elevation of blood chemistries (SGOT, SGPT, alkaline phosphatase, BUN) were noted in some patients. Six patients had transient depression of WBC counts (toxicity scores of 1 or 2) and two patients had transient depression of platelets (toxicity score of 1). None of these altered treatment. Forty-five patients received Fluosol of which 34 completed the planned therapy. Six patients were diangosed with metastatic disease during therapy and three patients died of their disease during treatment. One patient was withdrawn due to ineligibility and one patient withdrawn due to moderate reactions to Fluosol during the 3rd and 4th infusions. The total dose of Fluosol was escalated from 42 mL/Kg to 49 mL/Kg in 5, 6, or 7 weekly infusions. Patients breathed 100% oxygen for a minimum of one-half hr prior to and during radiation treatment. Radiation therapy was administered at a daily fraction of 165 to 200 cGy per fraction to a total dose of 5940 to 6800 cGy. Seventeen of 34 patients (50%) achieved a complete response to treatment and 11 patients (32%) had a partial response. Thirteen patients remain alive (range of 12 to 20 months) including 10 of 17 complete responders, 2 of 11 partial responders, and 1 treated with chemotherapy postradiation. The median absolute survival time of the patients completing therapy was 15.5 months and the 12 and 18 month absolute survival rates were 81% and 74%, respectively. The 45 patients starting protocol therapy had a median absolute survival of 9.2 months with a 12-month and 18-month survival of 45% and 35%, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1990

A phase I/II study of the use of Fluosol as an adjuvant to radiation therapy in the treatment of primary high-grade brain tumors.

The main objective of this study was to evaluate the safety and efficacy of a perfluorochemical emulsion, Fluosol, with short-term high inspired oxygen tension as an adjuvant to radiation therapy in the treatment of high-grade tumors of the brain. Radiation was delivered to the whole brain at 1.8 Gy per daily treatment for 5 weeks to a total dose of 45 Gy. The radiation portals were then reduced in size to encompass the known volume of tumor, as determined by the presurgical contrast-enhancing ring on computed tomography (CT), plus a 3-cm margin. An additional 10 treatments of 2 Gy each were given to the smaller volume, to bring the total tumor dose to 65 Gy in 7 weeks. This report describes the experience of the first 18 patients treated at the University of Kansas Medical Center on this study, whose median follow-up time from the date of surgery is 77 weeks (62-115 w). Immediately following Fluosol administration on a Monday, patients breathed 100% oxygen for at least 45 minutes prior to and throughout their radiation treatment. On each subsequent day of the weeks in which they received Fluosol, patients breathed 100% oxygen. Hematology and blood chemistries were also drawn prior to Fluosol treatment each Friday during treatment and at the 2-week, 3-month, and 6-month follow-up visits. The median age of the patients was 45 years (16-72); 13 patients were male and 15 carried the diagnosis of glioblastoma multiforme (3 had anaplastic astrocytoma). Two thirds of the patients had an initial allergic reaction to the Fluosol consisting of back pain, shortness of breath, and flushing, but all responded to 50-100 mg of Benadryl. During radiation therapy, all patients developed scalp erythema and complete alopecia by the end of 3 weeks, but no patient required a treatment rest. The serum levels of SGOT, SGPT, and alkaline phosphatase were examined before and throughout the Fluosol treatment and, by week 5, 11/18 of the patients had increased values of all three enzymes above the upper range of normal. These increases persisted through the end of treatment, but most values returned to essentially normal by the 3-month follow-up visit. We conclude that Fluosol, given in the manner described above, appears to be associated with minimal significant side effects and no changes could be detected in the white matter of any of the patients at the time of their magnetic resonance imaging study at 6 months follow-up.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1990

Interaction of ethanol with enflurane metabolism and toxicity: role of P450IIE1.

Administration of enflurane (EF), a widely-used anesthetic agent, sometimes results in occult liver injury. As hepatic cytochromes P450 oxidize EF to a reactive intermediate, we assessed whether one such microsomal enzyme, ethanol-inducible P450IIE1, plays an obligatory role in EF metabolic activation and hepatotoxicity. Liver microsomes from rats fed ethanol (36% of total calories for 14 days) oxidized 1 mM EF (measured by its defluorination) at rates nearly 10-fold greater than those from control rats, reflecting the markedly enhanced content of immunoreactive microsomal P450IIE1 in the former animals. P450IIE1 involvement in hepatic EF oxidation was further suggested by the pronounced inhibition of microsomal defluorination noted with P450IIE1 antibodies and with ethanol, a specific substrate for this enzyme. EF administration to rats treated chronically with ethanol caused significant elevations in plasma levels of aspartate and alanine aminotransferases and glutamate dehydrogenase, indicative of hepatic injury, whereas concurrent treatment of naive rats with EF and ethanol failed to produce the same effect. Our results imply that ethanol-inducible P450IIE1 is the primary catalyst of hepatic EF bioactivation and that the increased bioactivation occurring in vivo secondary to chronic ethanol consumption is attendant with an increased incidence of EF hepatotoxicity.

Animals↗
PubMed1989

Multiple GF-1 binding sites flank the erythroid specific transcription unit of the human carbonic anhydrase I gene.

Six potential GF-1 sites which bind an erythroid factor are present in the 5' and 3' regions flanking the erythroid-specific transcription unit of the human carbonic anhydrase I (HCAI) gene. When two of these sites are placed upstream of a minimal eukaryotic promoter they confer up-regulated expression in erythroid over non-erythroid cells. The presence of the erythroid factor in TPA-treated HEL cells in which the level of HCAI transcript has greatly decreased and in non-HCAI-expressing K562 cells suggests that in these cases the presence of the factor is not sufficient for HCAI expression.

Base Sequence↗
PubMed1989

Nucleotide sequence of the aliphatic amidase regulator gene (amiR) of Pseudomonas aeruginosa.

The nucleotide sequence of a 1001 bp ClaI/XhoI DNA fragment encoding the amidase regulator gene (amiR) from Pseudomonas aeruginosa has been determined. The sequence derives from strain PAC433, a constitutive high expressing amidase mutant, and contains two overlapping open reading frames. Analysis of the sequence has identified one of the reading frames as amiR. The gene encodes a 196 amino acid polypeptide which shows a strong bias towards codons with G or C in the third position. The amiR gene shows no sequence homology with other bacterial regulator proteins.

Amidohydrolases↗
PubMed1989

Increased hepatic retinal dehydrogenase activity after phenobarbital and ethanol administration.

Cytosolic retinal dehydrogenase (EC 1.2.1.36, retinal: NAD+ oxidoreductase) activity was measured by assessing the conversion of retinal to retinoic acid by HPLC. In vitro, acetaldehyde, chloral hydrate and disulfiram were found to be inhibitors, whereas 95% of the activity remained in the presence of cyanide or in the absence of oxygen. In rats, retinal dehydrogenase activity prevailed over that of retinal oxidase. By contrast, in deermice, 80% of retinal oxidation was due to the oxidase rather than the retinal dehydrogenase activity in a normal strain (ADH+) as well as in one lacking alcohol dehydrogenase (ADH-). In ADH- deermice, retinal oxidase activity was greater than in ADH+ animals. In vivo, in the rat, chronic ethanol administration resulted in a significant increase of the dehydrogenase activity in the liver, but not in other tissues. After phenobarbital administration, hepatic retinal dehydrogenase activity was increased 8-fold, but no extrahepatic induction was observed. Conversely, feeding rats with a diet devoid of the precursor for the substrate (retinal) by replacing retinyl acetate with an equivalent amount of retinoic acid resulted in decreased retinal dehydrogenase activity. Under conditions in which retinal dehydrogenase activity is rate-limiting for the metabolism of retinal to retinoic acid, its induction after phenobarbital or ethanol administration may contribute to hepatic vitamin A depletion.

Aldehyde Oxidoreductases↗