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Biomedical subjects

C M Brown

Publications and source records attributed to C M Brown.

At least 271 records · Page 15Linked to original sources
PubMed1969

Effects of temperature on composition and cell volume of Candida utilis.

Candida utilis NCYC 321 was grown in steady-state culture in a chemostat under glucose limitation or NH(4) (+) limitation at temperatures of 30, 25, 20, and 15 C and at dilution rates (equal to growth rates) in the range of 0.35 to 0.05 hr(-1). Deoxyribonucleic acid contents of cells grown under the various conditions remained approximately constant, but the contents of several other cell components varied. Over the range of 30 to 15 C, the greatest differences were in the ribonucleic acid (RNA) and protein contents of cells grown under NH(4) (+) limitation, which increased as the temperature was decreased. The contents of other components, particularly adenosine triphosphate in cells grown under glucose limitation, varied more when the cells were grown at different rates at a fixed temperature. Cells grown at a fixed rate under NH(4) (+) limitation increased in volume as the temperature was decreased below 30 C. The increase in volume was closely correlated with increases in the proportions of RNA and protein in the dry weight of cells. Cells grown under glucose limitation showed much smaller increases in volume; these increases were poorly correlated with the increased RNA content and hardly at all with the increased protein content. Increases in volume with a decrease in growth temperature from 30 to 20 C were also demonstrated in cells grown under phosphate limitation and to a much smaller extent in cells grown under glycerol limitation. The increased RNA synthesized at low temperatures by cells grown under NH(4) (+) limitation was found almost exclusively in the 40,000 x g supernatant fluid, but only about 40% of it sedimented at 100,000 x g. Cells grown at a fixed rate under NH(4) (+) limitation synthesized less total carbohydrate when the temperature was decreased from 30 to 15 C. This decrease was mainly in the trichloroacetic acid-soluble fraction (probably trehalose) and in the intracellular hot alkali-soluble glucan (probably glycogen). Cells grown at a fixed rate under glucose limitation showed a small increase in carbohydrate content as the temperature was decreased from 30 to 15 C.

Adenosine Triphosphate↗
PubMed1969

Fatty-acid composition of Candida utilis as affected by growth temperature and dissolved-oxygen tension.

Analyses were made of the fatty-acid composition of Candida utilis NCYC 321 grown in a chemostat at a dilution rate (equal to growth rate) of 0.1 hr(-1) and at temperatures in the range of 30 to 15 C and dissolved oxygen tensions between 75 and <1 mm of Hg. Cells grown under glucose limitation or NH(4) (+) limitation contained mainly C(16:0), C(16:1), C(18:0), C(18:1), C(18:2), and C(18:3) acids as detected by gas-liquid chromatography of methyl esters of the acids from lipids extracted with chloroform-methanol. The relative proportions of these acids varied with the growth temperature and the dissolved-oxygen tension in the culture. A decrease in growth temperature from 30 to 20 C led to an increased synthesis of unsaturated acids in cells grown under either limitation at a fixed-oxygen tension in the range of 75 to 5 mm of Hg. In cultures with a dissolved-oxygen tension of 1 and <1 mm of Hg, a further decrease in temperature to 15 C caused an increased synthesis of unsaturated fatty acids. A decrease in dissolved-oxygen tension led to a diminished synthesis of unsaturated fatty acids in cells grown at a fixed temperature under either limitation. Cells grown at a fixed temperature under glucose limitation synthesized a greater proportion of C(16) acids at the expense of C(18) acids as the dissolved oxygen tension was decreased from 75 to <1 mm of Hg. A preferential synthesis of C(16) acids also occurred as the growth temperature was decreased from 30 to 15 C in cells grown under glucose limitation at a fixed-oxygen tension. The same effect was observed in cells grown under NH(4) (+) limitation when the temperature was lowered from 30 to 20 C; but when the temperature was decreased further to 15 C, the cells synthesized a slightly greater proportion of C(18) acids. Synthesis of a large proportion of C(16) acids was accompanied by an excretion of pyruvate, and occasionally traces of 2-ketoglutarate, and an increased intracellular accumulation of certain amino acids.

Ammonia↗
PubMedDate not supplied

The diagnostic value of the D-xylose absorption test in horses with unexplained chronic weight loss.

A D-xylose absorption test was performed on 40 horses with chronic weight loss which could not be explained on history, physical findings, dietary evaluation, or initial laboratory data, i.e. unexplained weight loss. Six of the horses had D-xylose malabsorption and at post-mortem examination small intestinal lesions which accounted for the malabsorption were found in five. Five of the horses with normal absorption were examined post mortem and no lesions in any organs were found to account for the weight loss. The other 29 cases were still unexplained, and lost to follow-up.

Animals↗
PubMedDate not supplied

Use of alternative therapies and their impact on compliance: perceptions of community pharmacists in Texas.

OBJECTIVE: To assess community pharmacists' experiences with the use of alternative therapies by their patients with chronic illnesses. DESIGN: Mail survey. SETTING: State of Texas. PARTICIPANTS: 142 community independent and chain pharmacists. MAIN OUTCOME MEASURES: Pharmacists' recollections about patients' use of alternative therapies. RESULTS: Pharmacists estimated that 17% of their patients with chronic illnesses used some form of alternative therapy. A majority (66.9%) indicated that they have patients who used some type of alternative therapy for chronic conditions and that a majority (59.7%) of these patients consulted with them regarding those therapies. However, in only 11.1% of these cases did pharmacists document alternative therapy use in patients' pharmacy records. Pharmacists reported that 25.9% of these patients who use alternative therapies for chronic conditions were not compliant with their prescribed medication regimen. One-third (33.1%) of respondents indicated they knew of no patients who used alternative therapies, and 35.9% had never asked. CONCLUSION: Pharmacists need information on patients' use of alternative therapies for chronic illnesses to make valid therapy decisions and to monitor outcomes. Future research should identify actions that pharmacists take to address drug-related problems among alternative therapy users and assess the impact of these actions on drug therapy-related outcomes.

Adult↗
PubMedDate not supplied

Use of herbal remedies by patients in a health maintenance organization.

OBJECTIVE: To examine the use of and experiences with herbal remedies among a group of patients enrolled in a health maintenance organization (HMO). DESIGN: Self-administered questionnaire. SETTING: Central Texas city. PARTICIPANTS: 135 HMO patients. INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE: Patients' self-reported use of herbal remedies. RESULTS: Almost 40% of patients indicated they had used herbal remedies. The majority had used herbal remedies to treat or prevent a health condition (e.g., common cold). The remedies most frequently used were garlic, aloe gel, cranberry, and echinacea. Most respondents gathered their information on herbal remedies from the popular media, and most based their use decisions primarily on the recommendations of friends and/or relatives. Although most were unsure of the quality of the products, they felt they were safe and somewhat effective, and few had experienced any direct side effects they attributed to the herbal remedies. Most patients used the products without the knowledge of their physician or pharmacist. Herbal remedies were most often used in place of prescription or over-the-counter (OTC) medications and most frequently purchased in health food stores and mass merchandizer/grocery stores. Herbal remedies were sometimes used along with prescription or OTC medications. CONCLUSION: Given that patients are using herbal remedies for a variety of health conditions without medical supervision, pharmacists need to actively and consistently obtain information about herbal remedy use to effectively advise patients and monitor outcomes. More research is needed on herbal remedy use among patient populations and on outcomes in patients who use herbal remedies to treat primary health conditions.

Adult↗
PubMedDate not supplied

Equine degenerative myeloencephalopathy: a vitamin E deficiency that may be familial.

Two horse farms, on which there was a high incidence of proven and suspected equine degenerative myeloencephalopathy (EDM), were studied. Symmetric ataxia and paresis, along with laryngeal adductor, cervicofacial, local cervical, and cutaneous trunci hyporeflexia, characterized the syndrome. Serum vitamin E concentration reflected a deficient state in affected and unaffected horses on both farms when compared with selected reference groups and with published values. A high incidence of the disease was evident in offspring of two particular sires on one farm. Vitamin E supplementation resulted in correction of the deficient state in most horses and was associated with a drastic reduction in the incidence of EDM on one farm from 40% to less than 10% the year following vitamin E supplementation. In addition, during the last year, the severity of signs in the few cases was dramatically reduced. This information substantiates the hypothesis that EDM is a vitamin E-responsive disorder of Equidae with a possible familial predisposition.

Animals↗
PubMedDate not supplied

Translational termination efficiency in both bacteria and mammals is regulated by the base following the stop codon.

The translational stop signal and polypeptide release factor (RF) complexed with Escherichia coli ribosomes have been shown to be in close physical contact by site-directed photochemical cross-linking experiments. The RF has a protease-sensitive site in a highly conserved exposed loop that is proposed to interact with the peptidyltransferase center of the ribosome. Loss of peptidyl-tRNA hydrolysis activity and enhanced codon-ribosome binding by the cleaved RF is consistent with a model whereby the RF spans the decoding and peptidyltransferase centers of the ribosome with domains of the RF linked by conformational coupling. The cross-link between the stop signal and RF at the ribosomal decoding site is influenced by the base following the termination codon. This base determines the efficiency with which the stop signal is decoded by the RF in both mammalian and bacterial systems in vivo. The wide range of efficiencies correlates with the frequency with which the signals occur at natural termination sites, with rarely used weak signals often found at recoding sites and strong signals found in highly expressed genes. Stop signals are found at some recoding sites in viruses where -1 frame-shifting occurs, but the generally accepted mechanism of simultaneous slippage from the A and P sites does not explain their presence here. The HIV-1 gag-pol-1 frame shifting site has been used to show that stop signals significantly influence frame-shifting efficiency on prokaryotic ribosomes by a RF-mediated mechanism. These data can be explained by an E/P site simultaneous slippage mechanism whereby the stop codon actually enters the ribosomal A site and can influence the event.

Animals↗
PubMedDate not supplied

Hypophosphatemia induced in mice by transplantation of a tumor-derived cell line from a patient with oncogenic rickets.

A cultured cell line was derived from a hemangiopericytoma obtained at surgery from a 9 year-old boy with hypophosphatemic rickets. Hypophosphatemia and metabolic bone disease were cured in the patient after tumor removal. Cells from passage 5 were transplanted into 8 week-old athymic female mice. Additional animals received innocula of cells thawed from the stored original tumor tissue, as well as MRC-5 fibroblasts. Serum phosphate levels 3-7 months post-transplantation were lowest in mice which received the cultured cell line (n = 5) 6.1 +/- 0.6 mg/dl (p < 0.05 compared to the other groups), thawed tumor cells (n = 8) 7.2 +/- 0.7 mg/dl, MRC fibroblasts (n = 4) 8.1 +/- 1.0 mg/dl, no transplant (n = 10) 8.7 +/- 1.9 mg/dl. Repeat of the experiment with cultured tumor cells from passage 12 no longer altered phosphate levels. A substance produced and release by the tumor in situ and by tumor-derived cultured cells is capable of producing hypophosphatemia. Experimental manipulation of functional tumor-derived cell lines may help elucidate the factor(s) causing hypophosphatemia in oncogenic osteomalacia/rickets.

Animals↗
PubMedDate not supplied

Masticatory function in patients with juvenile rheumatoid arthritis.

PURPOSE: Children with Juvenile Rheumatoid Arthritis (JRA) rarely report temporomandibular joint (TMJ) pain, which may be due to pain avoidance mechanisms resulting in compromised masticatory function. This study examined the relationship between self-report measures of pain and dysfunction and measures of chewing performance in 44 JRA children and 34 normal controls. METHODS: The children were divided into three groups: Group 1, JRA children with temporomandibular joint disorder (TMD); Group 2, JRA children without TMD; Group 3, normal control children without TMD. Both visual and analog scales of jaw pain, ability to chew, and quality of life were administered before and after chewing tasks. Children chewed standardized portions of an artificial food for 20 cycles and expectorated the particles into a cup. This process was repeated five times. Median particle size and a broadness of particle distribution index were measured. Also, the number of chewing cycles prior to the child's first swallow for a cube of carrot was recorded. RESULTS: The broadness of particle distribution index was greater for Group 1 (P < 0.001) and Group 2 (P < 0.03) than for Group 3 with no difference in number of chews for carrot mastication among groups. Group 1 reported more pain and dysfunction before the chewing tasks than Groups 2 or 3 (P < 0.05). Interestingly, only Group 3 reported increased pain and decreased ability to chew after chewing tasks (P < 0.02). CONCLUSION: Children with JRA compromise their masticatory function as a pain avoidance mechanism. Such findings may have profound implications with regard to the nutritional status for these children.

Adolescent↗
PubMedDate not supplied

Antiretroviral adherence and use of alternative therapies among older HIV-infected adults.

OBJECTIVE: To investigate adherence to antiretroviral therapy and use of alternative therapies among older human immunodeficiency virus (HIV)-infected adults, and to assess relationships between antiretroviral adherence and clinical outcomes. METHODS: One hundred older HIV-infected patients, aged 50 and over, treated at two large HIV clinics in Washington, DC, were enrolled. A cross-sectional methodology used structured interviews to investigate antiretroviral regimens, use of alternative therapies, and demographics. Medical records provided viral load and CD4 count within 3 months of interview. RESULTS: The mean self-reported adherence was 94%, and 55 patients reported 100% adherence to antiretroviral therapy. Correlation analysis showed a significant negative correlation between adherence and viral load (r = -312, p = 0.005). There was no significant difference in adherence based on race, gender, mode of transmission, or education. Twenty-one patients (21%) reported the use of an alternative therapy, with several patients using multiple alternative therapies. There was no significant difference in adherence score (p = 0.514) or viral load (p = 0.860) based upon use of alternative therapies. CONCLUSIONS: Older HIV-infected study patients reported high levels of adherence to antiretroviral regimens, and adherence was highly correlated with HIV viral load. Use of alternative therapies did not significantly impact adherence to antiretroviral agents or viral load. High adherence among this older population may be related to older patients' familiarity with medication usage, their increasing awareness of HIV as a disease that requires optimal adherence, and educational efforts promoted by the two clinics in which they are clients.

Anti-HIV Agents↗