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Biomedical subjects

R Jones

Publications and source records attributed to R Jones.

At least 631 records · Page 35Linked to original sources
PubMed1991

Three psychological treatments for bulimia nervosa. A comparative trial.

The specificity and magnitude of the effects of cognitive behavior therapy in the treatment of bulimia nervosa were evaluated. Seventy-five patients who met strict diagnostic criteria were treated with either cognitive behavior therapy, a simplified behavioral version of this treatment, or interpersonal psychotherapy. Assessment was by interview and self-report questionnaire, and many aspects of functioning were evaluated. All three treatments resulted in an improvement in the measures of the psychopathology. Cognitive behavior therapy was more effective than interpersonal psychotherapy in modifying the disturbed attitudes to shape and weight, extreme attempts to diet, and self-induced vomiting. Cognitive behavior therapy was more effective than behavior therapy in modifying the disturbed attitudes to shape and weight and extreme dieting, but it was equivalent in other respects. The findings suggest that cognitive behavior therapy, when applied to patients with bulimia nervosa, operates through mechanisms specific to this treatment and is more effective than both interpersonal psychotherapy and a simplified behavioral version of cognitive behavior therapy.

Adolescent↗
PubMed1991

p80cdc25 mitotic inducer is the tyrosine phosphatase that activates p34cdc2 kinase in fission yeast.

We have investigated the mechanism by which fission yeast p80cdc25 induces mitosis. The in vivo active domain was localized to the C-terminal 23 kDa of p80cdc25. This domain produced as a bacterial fusion protein (GST-cdc25) caused tyrosyl dephosphorylation and activation of immunoprecipitated p34cdc2. Furthermore, GST-cdc25 dephosphorylated both para-nitrophenyl-phosphate (pNPP) and casein phosphorylated on serine in vitro. Reaction requirements and inhibitor sensitivities were the same as those of phosphotyrosine phosphatases (PTPases). Analysis of cdc25 C-terminal domains from a variety of species revealed a conserved motif having critical residues present at the active site of PTPases. Mutation of the cdc25 Cys480 codon, corresponding to an essential cysteine in the active site of PTPases, abolished the phosphatase activity of GST-cdc25. These data indicate that cdc25 proteins define a novel subclass of eukaryotic PTPases, and strongly argue that cdc25 proteins directly dephosphorylate and activate p34cdc2 kinase to induce M-phase.

Amino Acid Sequence↗
PubMed1991

Myelin basic protein specific T cell lines and clones derived from the CNS of rats with EAE only recognize encephalitogenic epitopes.

The epitope specificities of myelin basic protein (BP) specific T cell lines derived from the spinal cords (SC) and lymph nodes (LN) of rats with experimental autoimmune encephalomyelitis (EAE) were compared. To induce EAE, Lewis rats were immunized with guinea pig (GP)-BP and complete Freund's adjuvant. Mononuclear cells from the SC and LN of these animals proliferated in response to BP and the purified protein derivative (PPD) of mycobacterium. After initially being cultured in growth medium, SC mononuclear cells had an enhanced response to BP and lost their response to PPD. LN cells cultured in identical conditions lost their response to both BP and PPD. LN-derived BP specific cell lines recognized only two epitopes of GP-BP: an encephalitogenic epitope in residues 72-89 and a non-encephalitogenic epitope in residues 43-68. SC-derived BP specific cell lines and clones recognized the 72-89 epitope and a second encephalitogenic epitope contained in residues 87-99 but not the non-encephalitogenic 43-68 epitope. Unlike those from LN, BP-specific T cell lines and clones derived from the CNS appear to recognize only encephalitogenic epitopes, including epitopes not recognized by LN lines.

Animals↗
PubMed1991

Alterations in distribution of surface and intracellular antigens during epididymal maturation of rat spermatozoa.

The surface membrane of mammalian spermatozoa is known to undergo considerable conformational and organizational changes during epididymal maturation. However, much less is known about remodelling of intracellular membranes. In this communication we have used specific immunological markers to study the behavior of several antigens both on and within rat spermatozoa as they mature in the epididymis. Four monoclonal antibodies (McAbs) designated 5B1, 1B5, 2D6, and 1B6 were used to probe testicular and caput and cauda epididymal spermatozoa by indirect immunofluorescence and immunogold labeling techniques. None of the McAbs bound to testicular spermatozoa; in all cases, they became reactive only on spermatozoa which had reached the caput epididymis. McAb 5B1 was restricted to the outer acrosomal membrane (OAM) of the acrosomal cap domain. The epitope first appeared on antigen(s) with molecular mass (Mr) of approximately 200 kDa in immature spermatozoa, but later in mature spermatozoa the antigen(s) had Mr of approximately 160 kDa. The antigen(s) recognized by 1B5 McAb on the other hand was initially distributed over the OAM of the entire acrosomal domain (cap + equatorial segment), but during maturation it became progressively more restricted in area until in cauda spermatozoa only the anterior tip of the OAM bound the McAb. McAb 2D6 also bound to the entire OAM and acrosomal contents of caput spermatozoa, but, unlike 5B1 and 1B5 McAbs, reactivity was transient. That is, staining was first detected in caput spermatozoa but then disappeared in corpus and cauda spermatozoa. In contrast to all of the above, 1B6 McAb bound to the surface membrane overlying the entire head domain of caput spermatozoa, but during maturation it became restricted to the postacrosomal domain. These results indicate that, in addition to remodeling of the surface membrane during epididymal maturation, extensive processing of intracellular membrane antigens also takes place and that it is very active within the acrosome. The nature of these intracellular processing events remains to be elucidated, but they may have important consequences for membrane fusion and cell recognition phenomena during fertilization.

Animals↗
PubMed1991

Assessment of the hygienic adequacy of a commercial hot boning process for beef by a temperature function integration technique.

The hygienic performance of a commercial hot boning process for beef carcasses was assessed by a temperature function integration technique. The potential proliferation of Escherichia coli was calculated from 50 temperature histories for the persistently warmest, microbially contaminated regions of product passing through both the carcass cutting and carton cooling phases of the process. The maximum calculated proliferation was similar to, but the average proliferation was more than, the respective values previously obtained for a beef side cooling process that complied with Good Manufacturing Practice. After upgrading of the carton cooling facility the process was re-assessed. Then, for a sample of 50 temperature histories, the maximum proliferation was less than, and the average proliferation was similar to, the respective values for the side cooling process. Observed proliferations of E. coli inocula in cooling cartons of product were compared with the proliferations calculated from temperature histories obtained from sites close to inocula. The pairs of calculated and observed values mostly agree within +/- 1 generation.

Animals↗
PubMed1991

Capillary gas chromatography for the assessment of cholesterol oxides in the heart.

Recent studies indicated the presence of cholesterol oxides in biological tissues such as heart under pathophysiological conditions. Currently, no suitable method is available to separate and quantitate these oxides in biological tissues. This study was undertaken to develop a method suitable for the quantification of cholesterol oxides in heart. Since under normal conditions cholesterol oxidation does not occur, we exposed isolated perfused rat heart to oxygen-derived free radicals, which are known to oxidize cholesterol in heart. Free radical treated hearts were homogenized and lipids extracted by conventional techniques. The extracted lipids were saponified, and non-saponified portions were extracted with ether. Silyl derivatives of the extracted products were subjected to capillary gas chromatography. One microlitre of the sample was injected onto an SE 54 Supelco capillary column and run by stepwise temperature programming from 230 to 260 degrees C at a rate of 20 degrees C min-1, and then from 260 to 290 degrees C at 6 degrees C min-1. 5-Androsten-3 beta-ol-17-one was used as internal standard. The separated cholesterol oxides were identified by comparing with authentic standards. This method was suitable to separate 7 alpha-hydroxycholesterol, dihydroxycholesterol, 7 beta-hydroxycholesterol, 20 alpha-hydroxycholesterol, cholesterol-5 alpha,6 alpha-epoxide, and 5-cholestene in heart. Since some of these oxides are cytotoxic to the heart, identification of these oxides should be important to understand the pathophysiology of myocardial disease and for the successful therapy to prevent them.

Animals↗
PubMed1991

Mouse ferritin H multigene family is polymorphic and contains a single multiallelic functional gene located on chromosome 19.

Multiple ferritin H subunit sequences are present in the genome of higher vertebrates, but it is not yet known with certainty if more than one is expressed. In this paper, we provide evidence that there is only one functional ferritin H gene in the mouse. We screened a mouse genomic library using a mouse ferritin H cDNA as a probe and characterized five clones. These genomic clones proved to contain three pseudogenes and two allelic forms of a unique functional gene. These two alleles differed by only two point mutations in the promoter and three in the first intron and by a 31-bp insertion in the first intron. They were equally expressed when transiently transfected in HeLa cells. These five genomic clones account for all the bands observed on a Southern blot of mouse genomic DNA hybridized with a ferritin H cDNA, and these bands present a restriction fragment length polymorphism between various representatives of the genus Mus. Using a DNA panel prepared from the backcross progeny (C57BL/6 X Mus spretus)F1 X C57BL/6, we localized the functional ferritin H gene (Fth) in region B of mouse chromosome 19 and established cen-Ly-1-Fth-Pax-2 as the most likely gene order, thus defining a conserved syntenic fragment with human chromosome 11q.

Alleles↗
PubMed1991

Critical reading.

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Education, Medical, Continuing↗
PubMed1991

cdc25 M-phase inducer.

In this paper, we have described the critical experiments leading to the discovery and analysis of the cdc25 M-phase inducer. We have shown that timing of mitosis is sensitive to the level of cdc25+ expression and that the cellular concentration of p80cdc25 increases as cells approach mitosis. From these observations we conclude that, in S. pombe, rate of accumulation of p80cdc25 plays an important role in determining the timing of mitosis. We postulate that under a given set of conditions, a critical level of p80cdc25 activity is required to undergo mitosis. The actual level that is required can vary depending on ploidy, growth rate, nutritional status of the cell, and perhaps other parameters. These signals may be monitored through the weel pathway leading to tyrosyl phosphorylation of p34cdc2. We have shown that p80cdc25 encodes a phosphate that acts by directly dephosphorylating the Tyr-15 residue of p34cdc2. Our studies strongly indicate that this aspect of the mitotic control network is generally conserved among eukaryotes. It is conceivable, however, that the mode of regulation of cdc25 activity may vary from species to species. Clearly, in S. cerevisiae the cdc25+ homolog, MIH1, in contrast to cdc25+, is not rate-limiting for M-phase onset. It will be important to determine whether the level of cdc25+ homologs in other organisms also oscillates during the cell cycle, or whether their activity is controlled by localization or posttranslational mechanisms, such as phosphorylation. Furthermore, our finding of more than one cdc25+ homolog in a single species suggests an additional level of complexity to the control of M-phase onset by cdc25 in higher eukaryotes that will require further investigation.

Amino Acid Sequence↗
PubMed1991

Basal-cell carcinoma of the breast--treatment with retinoids.

Retinoids have previously been described in the treatment of cutaneous malignancies and premalignancies. A case is reported of a patient with multifocal basal-cell carcinoma treated with a synthetic aromatic derivative of retinoic acid (etretinate) which resulted in complete resolution of the carcinoma confirmed by microscopy.

Aged↗
PubMed1991

Nucleotide sequence and genetic analysis of the Azotobacter chroococcum nifUSVWZM gene cluster, including a new gene (nifP) which encodes a serine acetyltransferase.

Nucleotide sequence was obtained for a region of 7,099 bp spanning the nifU, nifS, nifV, nifW, nifZ, and nifM genes from Azotobacter chroococcum. Chromosomal mutations constructed at several sites within the locus confirmed a requirement for this region for expression of the molybdenum nitrogenase in this organism. The genes are tightly clustered and ordered as in Klebsiella pneumoniae except for two additional open reading frames (ORFs) between nifV and nifW. The arrangement of genes in A. chroococcum closely matches that described for Azotobacter vinelandii. The polypeptide encoded by ORF4 immediately downstream from nifV is 41% identical over 186 amino acids to the product of the cysE gene from Escherichia coli, which encodes serine acetyltransferase (SAT), a key enzyme in cysteine biosynthesis. Plasmids which potentially express ORF4 complemented E. coli JM39, a cysteine auxotroph which lacks SAT. SAT activity was detected in crude extracts of one such complemented strain. A strain of A. chroococcum carrying a chromosomal disruption of ORF4 grew normally with ammonium as the N source but more slowly than the parental strain when N2 was the sole N source. These data suggest that ORF4 encodes a nif-specific SAT required for optimizing expression of nitrogenase activity. ORF4 was assigned the name nifP. nifP may be required to boost rates of synthesis or intracellular concentrations of cysteine or methionine. Sequence identity between nifV and leuA gene products suggests that nifV may catalyze a condensation reaction analogous to that carried out by isopropylmalate synthase (LEUA) but in which acetyl coenzyme and alpha-ketoglutarate are substrates for the formation of homocitrate, the proposed product of NIFV activity.

Acetyltransferases↗
PubMed1991

Job sharing.

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Female↗
PubMed1991

Pathway and carbon sources for hepatic glycogen repletion in dogs.

The present studies were undertaken to quantitate the relative contributions of the indirect and direct pathways for hepatic glycogen repletion and to determine the role of splanchnic tissues in provision of C precursors used for the indirect pathway. For this purpose, we administered oral glucose (1.4 g/kg) enriched with [1-14C]glucose to 18-h fasted dogs and measured net hepatic and net gastrointestinal glucose, lactate, and alanine balance, hepatic and gastrointestinal fractional extraction [( 3H]lactate), release and uptake of lactate, as well as the total amount of hepatic glycogen formed from the oral glucose and the 14C labeling pattern of the glycogen-glucose C. Although net hepatic glucose uptake (8.7 +/- 0.6 g, 27% of the oral load) exceeded the amount of glycogen formed from the oral glucose (6.3 +/- 1.1 g), analysis of radioactivity in C-1 of the glycogen glucose indicated that nearly 50% of the glycogen was formed by the indirect pathway. Net hepatic uptake of lactate (1.4 +/- 0.1 g) and alanine (1.5 +/- 0.1 g) could account for greater than 90% of glycogen formed by the indirect pathway if all of the lactate and alanine taken up by the liver had been incorporated into glycogen. Release of lactate and alanine by splanchnic tissues approximated the amount of lactate and alanine taken up by the liver. However, in addition to taking up lactate, the liver also produced nearly as much lactate as the gastrointestinal tract (1.8 +/- 0.2 vs. 2.0 +/- 0.3 g, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Inhaled nitric oxide. A selective pulmonary vasodilator reversing hypoxic pulmonary vasoconstriction.

Background. The gas nitric oxide (NO) is an important endothelium-derived relaxing factor, inactivated by rapid combination with heme in hemoglobin. Methods and Results. Awake spontaneously breathing lambs inhaled 5-80 ppm NO with an acutely constricted pulmonary circulation due to either infusion of the stable thromboxane endoperoxide analogue U46619 or breathing a hypoxic gas mixture. Within 3 minutes after adding 40 ppm NO or more to inspired gas, pulmonary hypertension was reversed. Systemic vasodilation did not occur. Pulmonary hypertension resumed within 3-6 minutes of ceasing NO inhalation. During U46619 infusion pulmonary vasodilation was maintained up to 1 hour without tolerance. In the normal lamb, NO inhalation produced no hemodynamic changes. Breathing 80 ppm NO for 3 hours did not increase either methemoglobin or extravascular lung water levels nor modify lung histology compared with control lambs. Conclusions. Low dose inhaled NO (5-80 ppm) is a selective pulmonary vasodilator reversing both hypoxia- and thromboxane-induced pulmonary hypertension in the awake lamb [corrected].

Administration, Inhalation↗
PubMed1991

Endoscopic sinus surgery: outcome in 155 cases.

For this retrospective study of endoscopic sinus surgery, charts of 22 patients from a medical center and 133 patients from a private practice (N = 155) were reviewed. Preoperative complaints, clinical findings, computed tomographic evidence of extent of sinus disease, surgical outcome, possible predictors of success, and complications were considered. Indications for endoscopic surgery were persistence of symptoms despite aggressive medical therapy and radiologic evidence of a significant sinus abnormality. Median followup was 12 months. Hemorrhage occurred postoperatively in two patients (1.5%); 17 patients required additional endoscopic surgery. Overall, 140 (91%) patients believed that the surgery was beneficial. Patients with facial pain preoperatively showed the greatest improvement. All patients having simultaneous septoplasty (N = 64) had successful outcome. The total number of opacified sinuses was not a predictor of outcome, but opacificaiton of the sphenoid sinus correlated with a poorer outcome. The patients seen at the medical center had poorer results, but had a larger number of opacified sinuses, were more likely to have had previous sinus surgery, and were more likely to have underlying medical conditions contributing to their sinus disease.

Academic Medical Centers↗
PubMed1991

Epirubicin at two dose levels with prednisolone as treatment for advanced breast cancer: the results of a randomized trial.

Two hundred eleven patients with advanced breast cancer were randomized to receive either epirubicin (E) 50 mg/m2 and prednisolone (LEP) or E 100 mg/m2 and prednisolone (HEP). The intended treatment consisted of 16 courses of LEP or eight courses of HEP given at 3-weekly intervals. Reasons for stopping treatment early included progressive disease, stable disease without symptomatic improvement, or severe toxicity deemed intolerable by either the patient or physician. Toxicity was recorded at 3-weekly and response at 9-weekly intervals using the World Health Organization (WHO) criteria of response and toxicity. Two hundred nine patients were eligible for analysis, 98% of whom have been followed for more than a year. One hundred four patients received LEP and 105 HEP. Significantly worse myelosuppression, alopecia, nausea and vomiting, and mucositis were seen in the high-dose arm (P less than or equal to .001). More patients in the LEP arm stopped treatment before the fourth course than in the HEP arm, and the commonest reason for stopping was progressive disease. A similar median number of courses was given in each arm. There was a significantly higher response in the HEP arm (HEP - complete response [CR] + partial response [PR] = 41%, LEP - CR + PR = 23%). Despite this, no statistically significant differences was seen in overall survival or progression-free interval. The median survival for HEP and LEP was 44 and 46 weeks, respectively.

Adult↗