Mechanical thermostatic mixer valve for caloric irrigation.
Explore the source record for details and available documents.
Caloric Tests↗
Biomedical subjects
D Lawrence
Publications and source records attributed to D Lawrence.
Trisomy 13: a new recurring chromosome abnormality in acute leukemia.
A new recurring chromosome abnormality was identified in 8 of 621 consecutive successfully karyotyped adults with de novo acute leukemia. These eight patients had trisomy 13 as the sole cytogenetic abnormality. On central morphologic review, five cases were classified as subtypes of acute myeloid leukemia, one as acute mixed lymphoid and myeloid leukemia, one as acute lymphoid leukemia, and one as acute undifferentiated leukemia. Blasts of all eight cases expressed one or more myeloid differentiation antigens. Three also expressed T-lineage-associated antigens; however, none of these had rearrangement of the T-cell receptor beta, gamma, or delta genes. Four of six cases tested were TdT positive. All eight patients with trisomy 13 were treated with intensive induction chemotherapy; only three entered a short-lived complete remission. Survival of patients with trisomy 13 ranged from 0.5 to 14.7 months, and was significantly shorter than that of the remaining patients (median 9.5 v 16.2 months, P = .007). We conclude that trisomy 13 is a rare, recurring clonal chromosome abnormality in acute leukemia associated with a poor prognosis. Malignant transformation of an immature hematopoietic precursor cell is suggested by the expression of antigens characteristic of both the myeloid and lymphoid lineage, the high incidence of TdT positivity, and the morphologic heterogeneity in these leukemias.
Acute Disease↗
Degradation of crystallins from a psoriatic patient undergoing PUVA therapy.
Comparative physico-chemical and spectroscopic analyses were carried out in human lens proteins obtained from extracts of normal, senile and PUVA cataracts. Mass recovery analysis reveals a large protein concentration loss in the PUVA cataract relative to the normal lens and senile cataract. This protein loss parallels an increase in the degraded polypeptide chains. However, the tryptophan content (2.1 mol/mol of 20 kDa protein subunit) and the apparent fluorescence quantum yield (phi f = 0.056) of the tryptophan residues which are believed to be involved in the development of UV-induced cataracts are unchanged after age-related alterations and/or in vivo photochemistry associated with psoralen (8MOP) photosensitized reactions.
Aging↗
Transforming growth factor type beta 1 modulates the effects of basic fibroblast growth factor on growth and phenotypic expression of rat astroblasts in vitro.
In a search of the growth factors possibly involved in brain ontogenesis we have examined the effects of transforming growth factor beta 1 (TGF-beta 1) on the growth and phenotypic expression of rat astroblasts in primary culture. Along TGF-beta 1 elicited only a slight negative effect on the growth of these cells. However, this factor was found to modulate the mitogenic effects of other growth factors. On quiescent cells it potentiates the mitogenic effect of basic fibroblast growth factor (bFGF) but not that of other growth factors, namely, epidermal growth factor (EGF), platelet-derived growth factor (PDGF), and thrombin. TGF-beta 1 did not modulate significantly the stimulatory effect of these growth factors on the activity of the enzyme glutamine synthetase (GS); but kinetic studies showed that TGF-beta 1 delays the stimulation of GS activity. DNA synthesis monitored by the incorporation of [125I]iododeoxyuridine (125I-dUrd) was maximum after 24-30 h of treatment with bFGF. With bFGF plus TGF-beta 1 the maximum was shifted to 30-36 h. This shift is compatible with the idea that TGF-beta 1 induces responsiveness in some cells which are otherwise unresponsive to the mitogenic action of bFGF, and that this induction requires some time. This hypothesis is sustained by the observation that in cells treated for only 12 h with bFGF, the treatment with TGF-beta 1 for the same 12 h or for longer time did not stimulate significantly the cell growth. Stimulation occurred only when the bFGF treatment was continued after 12 h. Potentiation of the mitogenic effect of bFGF and shift of the maximum 125I-dUrd incorporation towards 24 h was seen with cells pretreated with TGF-beta 1. This potentiation effect decreased with increasing time between the two treatments. The potentiation effect of TGF-beta 1 is not mediated by an induction of new bFGF membrane receptors as seen by binding studies.
Animals↗
Blunted ACTH and cortisol response to afternoon tryptophan infusion in euthymic bipolar patients.
The serotonin precursor tryptophan was used to test neuroendocrine responses in remitted bipolar patients and controls. Tryptophan was administered in the afternoon when spontaneous cortisol secretion is lower than in the morning. Following pilot studies at various doses, 50 mg/kg L-tryptophan was given i.v. over 20 min to 11 patients and 14 controls. Controls demonstrated cortisol release, whereas the response curve for patients was indistinguishable from placebo. Differences between groups were significant at 15, 30, and 45 min. Changes in adrenocorticotropic hormone were consistent with those in cortisol. Prolactin and growth hormone levels increased in both patients and controls following tryptophan. Higher doses caused gastrointestinal upset in some subjects.
Adrenocorticotropic Hormone↗
Second annual meeting of the National Cooperative Vaccine Development Groups for AIDS. 15-18 October 1989; Fort Lauderdale, Florida.
In this short review of the three-day meeting on AIDS vaccine development where numerous scientific advances were described for the first time, it is nearly impossible to capture all of the highlights. Thus, areas such as advances in vaccine adjuvant development, standardized challenge pools for vaccine testing, novel approaches with retroviral vectors for construction of target cells for cellular immune assays, summaries from all of the international AIDS vaccine development programmes, and other topics which were covered at the meeting are not discussed above. In closing the meeting, W. Koff (NIAID) noted that 1989 represented the turning point for AIDS vaccine development, that pessimism had given way to cautious optimism, and that the fundamental focus had changed from 'if a vaccine could be developed' to 'when'. While several challenges still remain in the path toward development of a safe and effective vaccine, the meeting served both to focus the direction of the research agenda for the next year and to build new and stronger collaborations among the international network of scientists dedicated to the common goal of developing a safe and effective AIDS vaccine.
Acquired Immunodeficiency Syndrome↗
Prehospital i.v. therapy. Are we contributing to patient complications?
Explore the source record for details and available documents.
Asepsis↗
Learning from HMOs.
Successful HMOs share essential characteristics that need to be incorporated more fully and more widely in the future.
Health Maintenance Organizations↗
Fine needle aspiration biopsy in lymphoma.
Patients with lymphoma undergo excisional biopsy of an affected lymph node for initial classification of their disease because accurate classification depends on the histologic characteristics of the neoplasm. However, fine needle aspiration cytology has a role in the management of lymphoma patients, particularly in those with recurrent or residual masses following treatment. Moreover, immunologic markers, nucleic acid flow cytometry, cytogenetics, and molecular genetics, which do not depend on histologic characteristics and can be performed on fine needle aspirates, are acquiring more importance in the management of patients with these diseases, particularly in those with non-Hodgkin's lymphoma. These latter tests add objectivity to the cytologic diagnosis of the B-cell lymphomas and increase its accuracy. In most series, the accuracy of fine needle aspiration in patients with lymphoma approaches 90%, with minimal complication rates.
Biopsy, Needle↗
Purification of active human plasminogen activator inhibitor 1 from Escherichia coli. Comparison with natural and recombinant forms purified from eucaryotic cells.
Plasminogen activator inhibitor 1 (PAI-1) inhibits both tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) and, therefore, is an important regulator of plasminogen activation. We have developed eucaryotic and procaryotic expression systems for PAI-1 and characterized the recombinant glycosylated and non-glycosylated products, together with a non-recombinant natural control, produced in the histosarcoma cell line HT 1080. For eucaryotic expression, the PAI-1 cDNA was stably transfected into chinese hamster ovary cells (CHO cells), while procaryotic expression in Escherichia coli was examined after inserting the DNA sequence encoding the mature PAI-1 protein into an inducible expression vector. Recombinant PAI-1 from CHO cells was purified approximately 50-fold in two steps and was indistinguishable from natural PAI-1. Between 3% and 4% of total cellular protein in the procaryotic expression system consisted of PAI-1, from which it was purified approximately 30-fold, with yields of between 15% and 20%. This PAI-1 formed 1:1 complexes with uPA and also with the single- and two-chain forms of tPA. Kinetic analysis demonstrated that the procaryote-produced PAI-1 had an inhibitory activity towards all three forms of PA that resembled that of natural PAI-1 with association rate constants of approximately 10(7) M-1 s-1. In contrast to PAI-1 from eucaryotic cells, the PAI-1 from E. coli had an inherent activity equal to that of guanidine/HCl-activated natural PAI-1. The activity could not be increased by treatment with denaturants suggesting that the latent form of PAI-1 was absent. However, at 37 degrees C the procaryote-produced PAI-1 lost activity at the same rate as natural PAI-1, with approximately 50% of the activity remaining after 3 h. This activity could be partially restored by treatment with 4 M guanidine/HCl. E. coli-derived PAI-1, added to human plasma and fractionated by Sephacryl S-200 chromatography, eluted in two peaks that were similar to those obtained with guanidine-activated PAI-1 from eucaryotic cells, suggesting that it bound to the PAI-1-binding protein (vitronectin).
Animals↗
[Modulation, by transforming growth factor beta (TGF beta), of the mitogenic effect of fibroblast growth factor (FGF) on rat oligodendrocytes in culture].
The transforming growth factor beta (TGF beta) is a weak mitogen for rat oligodendrocytes grown in serum-free chemically defined medium. When these cells were treated by basic fibroblast growth factor (bFGF), which is the most potent known mitogen for cultured oligodendrocytes, together with TGF beta we observed that at low doses TGF beta potentiates the mitogenic effect of bFGF while at higher concentrations it partly inhibits this effect.
Animals↗
The organization of the human-plasminogen-activator-inhibitor-1 gene. Implications on the evolution of the serine-protease inhibitor family.
Plasminogen activator inhibitor 1 (PAI-1) is a member of the serine protease inhibitor super family (SERPINS) which is thought to play an integral role in the control of plasminogen activation. PAI-1 inhibits both tissue-type plasminogen activator and urokinase-type plasminogen activator and may therefore be implicated in the control of various physiological processes. We have isolated the PAI-1 gene including its 5'-flanking sequence. The gene was characterized by restriction enzyme analysis, Southern blotting and DNA sequencing of all the coding parts as well as the 5'-flanking region. The PAI-1 gene contains nine exons and eight introns distributed over approximately 12.3 kb of DNA. All exon/intron boundaries agree with the 'GT-AG' rule. To characterize the presumptive promoter region, 800 bp of the 5'-flanking region was sequenced and potential binding sites for transacting transcriptional factors were localized. The transcription initiation site was identified by S1 protection experiments and is located 25 base pairs downstream of a TATA consensus sequence. By aligning the gene structure of PAI-1 and four other SERPINS and extrapolating a general tertiary structure to these SERPINS, we find that most introns map between subdomain structures of the proteins. Evidence is presented supporting an intron loss model for the evolution of the SERPIN family.
Amino Acid Sequence↗
[3H]arginine vasopressin binding to rat brain: a homogenate and autoradiographic study.
Arginine-vasopressin (AVP) has been implicated as a putative central neurotransmitter or neuromodulator in some brain functions. This study demonstrates binding of [3H]AVP to rat brain homogenates that is pH and temperature dependent, is saturable (Kd = 0.77 nM, Bmax = 0.374 pmol/mg) and reversible. A number of AVP analogues competitively displaced the [3H]AVP binding, indicating that central AVP binding sites may have a resemblance to the peripheral (V1) AVP vasopressor receptor. Homogenate binding occurred predominantly in the microsomal fraction (P3) of the hypothalamus while in the hippocampus and septum binding was predominantly in the synaptosomal fraction (P2). Autoradiographic methods showed displaceable [3H]AVP binding in the lateral septum, amygdala, supraoptic, paraventricular and suprachiasmatic nuclei of the hypothalamus supporting the results of homogenate binding in preparations of these regions.
Animals↗
Inhibition of the proliferative response of human B lymphocytes to B cell growth factor by transforming growth factor-beta.
The effects of transforming growth factor-beta (TGF-beta) on the proliferative response of human B cells to the low molecular weight B cell growth factor (BCGF) have been investigated in this study. It was found that TGF-beta, at picomolar concentrations, strongly inhibited the BCGF-induced proliferation of anti-mu chain or Staphylococcus aureus Cowan I-activated human B cells and also of a BCGF-dependent cell line derived from a human lymphocytic nodular lymphoma. This inhibitory effect was detected in normal and serum-free culture conditions. The suppression was greatly reduced when TGF-beta was added to the culture one day after BCGF and could be reverted by removing TGF-beta from the culture medium. Since TGF-beta has been detected in supernatants from activated T cells, this factor may represent an important regulatory molecule in the feedback control of B cell activation.
Antibodies, Anti-Idiotypic↗
Cost busters fair: increasing staff awareness of cost effective practice.
Losses in excess of $1,000,000 from uncharged supplies, which were inadequately documented in the medical record, prompted the formation of a multidepartmental task force to attack the problem. A project, the Co$t Busters Fair, was planned and developed to target nurses, physicians, nursing assistants, and medical attendants. Goals of the fair were to increase awareness of factors affecting cost and to clarify misconceptions about charting practices.
Anniversaries and Special Events↗
Modulation of intracellular glutathione concentrations alters lymphocyte activation and proliferation.
Glutathione (GSH) has been implicated in lymphocyte activation and differentiation, as well as in protection from radiation damage. Since [3H]thymidine ([3H]TdR) at high concentrations in the nucleus causes radiation damage to the cells, it is important to rule out the possibility that changes in [3H]TdR uptake by mitogen-activated lymphocytes are not caused by 3H-induced cell injury following alterations in intracellular GSH concentration. In this study, flow-cytometric analysis of cell cycle was used to measure lymphocyte activation. Intracellular GSH levels were enhanced using 2-L-oxothiazolidine-4-carboxylate (OTC) and 2-mercaptoethanol (2ME), which deliver cysteine intracellularly, and suppressed by buthionine sulfoximine (BSO) which inhibits gamma-glutamylcysteine synthetase. Enhancement of intracellular GSH concentrations in lymphocytes with 2-oxothiazolidine-4-carboxylate or 2-mercaptoethanol augments mitogen-induced lymphocyte activation, and proliferation, while suppression of intracellular GSH levels by buthionine sulfoximine inhibits the progression of cellular proliferation--but not activation, as measured by flow cytometry. There was a linear relationship between intracellular GSH concentration and conA-activated cells by flow cytometry and between GSH concentration and [3H]TdR incorporation as measured at 24 h. We conclude that alterations of intracellular GSH concentrations may be one way to modulate lymphocyte activation and differentiation.
Acridine Orange↗
Fibrinolytic system of cultured endothelial cells: regulation by plasminogen activator inhibitor.
Cultured bovine aortic endothelial cells have a relatively complex fibrinolytic system that is responsive to both the physiological state of the cell itself and to a variety of agents added to the culture medium. The fibrinolytic activity of these cells results from the production of both urokinase-type and tissue-type plasminogen activators and is regulated by an inhibitor capable of neutralizing their activities. The properties of these fibrinolytic components will be reviewed, and their respective roles in initiating and regulating the fibrinolytic activity of the cells will be summarized. A cDNA coding for the inhibitor has been isolated, and its sequence will be compared to that of other serine proteinase inhibitors.
Animals↗
Epidemic Reiter's syndrome following an outbreak of shigellosis.
We prospectively studied the occurrence of Reiter's syndrome (RS) or reactive arthritis (ReA) in 205 of 349 cruise-ship passengers who attended a buffet ashore and developed Shigella flexneri 2a enteritis. Five passengers probably had RS/ReA and 16 were possible or doubtful cases of RS/ReA. HLA-B27 was identified in 4 of 5 probable RS cases, but was not present in any of the 16 possible or doubtful cases nor in any of 20 passengers (controls) without any symptoms of RS/ReA. There was no statistically significant difference in the frequency of B7-Creg antigens in persons with possible or doubtful RS/ReA (9/16) compared to controls (8/20).
Adult↗