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Biomedical subjects

M Smith

Publications and source records attributed to M Smith.

At least 667 records · Page 37Linked to original sources
PubMed1994

Amino acid metabolism by hepatocytes in a hybrid liver support bioreactor.

The amino acid patterns of medium perfusate in a liver cell bioreactor developed for a hybrid liver support system have been measured. There were considerable changes in the concentrations of glutamic acid, glutamine, alanine, arginine, ornithine and branched chain amino acids during the first 10 days which is indicative of dynamic cellular metabolism. From day 15, steady state conditions of nitrogen metabolism are reflected by stable amino acid turnover. Monitoring of urea, K+, and P-450 activity suggests that hepatocytes have switched to a stable protein synthesis with a general amino acid uptake and keto acid release following cell volume increase.

Amino Acids↗
PubMed1994

Compliance devices preferred by elderly patients.

Many elderly patients take several medications for chronic conditions, a situation which causes problems in compliance with drug regimens. This study surveyed patients' preferences among four devices designed to make compliance easier: rub-off reminder labels, medication organizer trays, a container cap with a modified alarm clock, and a digital elapsed timer. Thirty-one enrolled patients used each device for one month then reported their ratings of four device attributes--clarity of directions for use, ease of use, convenience, and effectiveness in preventing dosing errors. The patients showed a strong preference for the medication organizer tray and generally preferred less-complex devices to those that were more difficult to learn to use.

Aged↗
PubMed1994

Alpha-keto acid metabolism by hepatocytes cultured in a hybrid liver support bioreactor.

Isolated pig liver cells cultured using a perfusion technique were analyzed over 39 days to test their ability to change the perfusate alpha-keto acid profile. While the pyruvate concentration in the culture medium decreased as of the first day, the alpha-ketoglutarate (KG), alpha-ketoisocaproate (KIC), alpha-ketoisovalerate (KIV) and alpha-keto-beta-methyl-n-valerate (KMV) were synthesized immediately and released by the liver cells. The metabolic capacity of the cell culture system increased up to day 10, decreased during the following 5 days and reached a steady state beyond day 15, which was maintained for at least 30 days. The branched chain alpha-keto acid release, in particular alpha-ketoisocaproate, reflects an effective transamination capacity of the newly developed culture system and shows an intact protein biosynthesis for at least 30 days in vitro.

Animals↗
PubMed1994

Genetic mapping of a locus for multiple epiphyseal dysplasia (EDM2) to a region of chromosome 1 containing a type IX collagen gene.

Multiple epiphyseal dysplasia (MED) is a dominantly inherited chondrodysplasia characterized by mild short stature and early-onset osteoarthrosis. Some forms of MED clinically resemble another chondrodysplasia phenotype, the mild form of pseudoachondroplasia (PSACH). On the basis of their clinical similarities as well as similar ultrastructural and biochemical features in cartilage from some patients, it has been proposed that MED and PSACH belong to a single bone-dysplasia family. Recently, both mild and severe PSACH as well as a form of MED have been linked to the same interval on chromosome 19, suggesting that they may be allelic disorders. Linkage studies with the chromosome 19 markers were carried out in a large family with MED and excluded the previously identified interval. Using this family, we have identified an MED locus on the short arm of chromosome 1, in a region containing the gene (COL9A2) that encodes the alpha 2 chain of type IX collagen, a structural component of the cartilage extracellular matrix.

Child↗
PubMed1994

[An educational program for blind infants. 1969].

Our longitudinal studies of blind infants have provided us with new information regarding the adaptive problems in the sensori-motor period and the impediments to development posed by blindness. We have reason to believe that some of the severe ego disturbances and cognitive deficits commonly found among blind children have their origins in the first eighteen months of life during the critical period of ego formation. As our research has progressed we have been able to translate these findings into a program of education and guidance for the blind infant which may be of interest to other professionals working with the blind. In this essay we will describe some aspects of our educational work with the blind baby and his parents and place our report within the context of our research findings.

Blindness↗
PubMed1994

Is LEEP a feasible addition to the family physician's office?

BACKGROUND: Seven thousand women die annually from cervical cancer in the US. This disease is preventable if cervical dysplasia is treated. Loop Electrosurgical Excision of the Cervix (LEEP) is a new treatment for dysplasia. This study evaluates the acceptability and feasibility of having LEEP available in a family physician's office. METHOD: We performed a retrospective audit of colposcopy patients at 2 family practice clinics over a 2-year period. We determined the patients who met criteria for LEEP, surveyed the patients and calculated the cost benefit to the clinic. RESULT: Out of 288 patients undergoing colposcopy, 40 (14%) were candidates for LEEP. Few complications, minimal discomfort, and performance of the procedure at their primary clinic were important to patients. Patient cost for LEEP in the office is $700 compared to $1450 in the hospital. Nine LEEP procedures per year provides a break-even point for the clinic. CONCLUSION: LEEP offers the advantage over laser treatment of lower cost, use of local anesthesia, and provision of a pathology specimen. Performing LEEP in the family physician's office is cost effective and meets patient needs.

Adult↗
PubMed1994

[Chylous cyst of the mesentery in adults. Apropos of a case].

Chylous cysts are in frequent entities which may have a variable pathogenesis. Their clinical and radiological presentation is fairly similar in each case report. Their CT appearance is very specific, but only histopathology can certify their etiology and their benign nature.

Adult↗
PubMed1994

Assessment of oral malodor in dogs.

This paper describes a methodology for measuring and assessing changes in canine oral malodor with the intent that it can be used to evaluate products designed to make pets' breath more acceptable to their owners. Ten judges, able to discriminate and rank malodorous chemical compounds, were trained as a formal sensory panel by an expert in sensory evaluation techniques. The panel was assembled to determine changes in oral malodor resulting from dietary manipulation. A dry experimental food served as the test food, and a commercial dry dog food as the reference food. Dogs fed the experimental food developed significantly less oral malodor (p < 0.01) than when they were fed the control food.

Animal Feed↗
PubMed1993

The introduction of external cephalic version at term into routine clinical practice.

External cephalic version (ECV) at > or = 37 weeks' gestation in suitable women with breech presentation was introduced in 1991 as a new management option at a University Teaching Hospital. After 16 months, the policy was audited by analysing a prospectively collected database of women offered ECV at term and by a retrospective review of all breech deliveries during the same period. A total of 52 women had ECV attempted with an immediate success rate of 46%. Four other cases had undergone spontaneous version by the time they attended for ECV. Of the remaining 72 breech deliveries, 49 were known to be breech and were not offered ECV; 39 of these had no contraindication (28% failure to offer ECV). Of the breech presentations, 22 remained undiagnosed until labour (18% of total study group). These results suggest that ECV at term can be introduced safely and without difficulty, with a strict protocol. Whilst the overall impact of ECV at term in clinical practice may be limited, if some vaginal breech deliveries and caesarean sections can be avoided it is a useful addition to the antenatal management of individual women with breech presentation.

Breech Presentation↗
PubMed1993

5-fluorouracil and interferon-alpha-2a in advanced colorectal cancer. Results of two treatment schedules.

BACKGROUND: Potential synergy between 5-fluorouracil (5-FU) and interferon alpha-2a (IFN-alpha-2a) has been demonstrated in the treatment of colorectal carcinoma. Continuous low-dose infusion of 5-FU may have superior response rates to bolus 5-FU in these malignancies. This report presents results of two Phase II trials using these principles in colorectal cancer. METHODS: Forty-eight patients were entered onto two protocols; 18 were treated with 5-FU by a bolus infusion schedule with concurrent IFN-alpha-2a (Group 1). Thirty patients were treated with continuous low-dose 5-FU and IFN-alpha-2a thrice weekly (Group 2). RESULTS: The overall response rates were 33% (95% confidence interval [CI], 16-68%) and 33% (95% CI, 17-53%), respectively, for Groups 1 and 2. In Group 2, in 16 previously untreated patients, there was a response rate of 56% (95% CI, 30-80%). The median survival was 11 months and 6 months for Groups 1 and 2, respectively. Toxicity in Group 1 was as expected, except the incidence of central nervous system toxicity was low, with only one patient requiring dose reduction because of cerebellar ataxia. The toxicity in Group 2 was substantial, with four patients being removed from study because of toxicity and all patients treated for more than 2 months requiring dose reductions. The most common (67%) toxicity was mucositis, with 33% of those patients classified as Grade III or IV (Southwest Oncology Group criteria). Other major toxicities were fatigue and hand/foot syndrome. CONCLUSIONS: The first trial confirms previous response rate data for bolus injection 5-FU and IFN-alpha-2a. The second trial of low-dose continuous infusion 5-FU with IFN-alpha-2a demonstrates similar efficacy with substantially greater toxicity.

Adenocarcinoma↗
PubMed1993

Peptide selection by class I molecules of the major histocompatibility complex.

Class I molecules of the major histocompatibility complex (MHC) bind peptides derived from cytoplasmic proteins. Comparison of over 100 such peptides reveals the importance of the carboxy-terminal residue in selective binding. Recent evidence implicates the proteases and transporters of the processing pathway in providing peptides with the correct residues at the carboxyl terminus.

Journal Article↗
PubMed1993

Concussive brain injury is associated with a prolonged accumulation of calcium: a 45Ca autoradiographic study.

In order to determine the extent and duration of calcium (Ca2+) flux following a lateral fluid percussion brain injury in the rat, 45Ca autoradiography was used to study animals immediately, 6, 24 and 96 h after the insult. In addition, cell suspension studies were conducted to determine the extent of cellular flux of 45Ca. Optical density and/or scintillation counting was utilized to provide a relative measure of 45Ca accumulation within 20 different structures. The results indicated that in animals who exhibited no gross morphological damage, 45Ca accumulation following injury was exhibited primarily within the ipsilateral cerebral cortex, dorsal hippocampus and striatum. This accumulation continued for several days returning to control levels by the 4th day after injury. In animals who sustained morphological damage, the contusion site exhibited a marked accumulation of 45Ca which did not resolve spontaneously over the course of 4 days. We conclude from this work that Ca2+ flux is a major component of this experimental model of traumatic injury. Furthermore, that depending on the extent of cell damage, the accumulation of Ca2+ is regionally different. Finally, that even in an injury which by itself does not produce gross morphological tissue damage, accumulation of Ca2+ can continue for at least 48 h.

Animals↗
PubMed1993

Partial functional mapping of the human interleukin-8 type A receptor. Identification of a major ligand binding domain.

We have previously demonstrated that a basic amino acid residue of interleukin (IL)-8, namely Arg-6, is critical for the binding of IL-8 to its receptor. We reasoned that this residue is likely to be poised to directly interact with a counterpart acidic residue on the receptor. To identify this key residue, we systematically mutated to Ala all acidic residues present on the ligand accessible surface of IL-8 receptor type A. Using this strategy, we demonstrate that two residues which are present in extracellular loop 3 of the receptor, namely Glu-275 and Arg-280, are critical for ligand binding. In addition, we show that although Asp-11 is critical for ligand binding, a conservative mutation of Asp-11 to Glu or a substitution of Asp-11 with Lys (the residue found at position 11 in IL-8 receptor type B) does not affect the Kd of the receptor/ligand interaction. These data suggest that Lys-11 recruits a new and favorable interaction with IL-8 (analogous to that of IL-8 receptor type B with IL-8) or that the cavity created by mutating Asp-11 to Ala is particularly deleterious. Finally, we discuss fluorescence-activated cell sorter staining data which support the hypothesis that the N-terminal region and the extracellular loop 3 of the receptor may lie in close proximity of one another and constitute a major binding domain for IL-8.

Alanine↗
PubMed1993

Aqueous tube-shunt implantation and pars plana vitrectomy in eyes with refractory glaucoma.

We reviewed the surgical outcome of 20 eyes of 20 consecutive patients who had undergone combined aqueous tube-shunt implantation and vitrectomy for complicated glaucoma associated with vitreoretinal disorders. After a mean follow-up of 10.39 +/- 5.43 months, visual acuity remained stable or improved in 13 patients (65%), and intraocular pressure was controlled (< 22 mm Hg) in 15 (75%). The most common complications were corneal edema (seven eyes) and choroidal effusion (three eyes). Combined tube-shunt implantation and pars plana vitrectomy may successfully control intraocular pressure and maintain preoperative visual acuity in refractory glaucoma associated with vitreoretinal disorders.

Adolescent↗