Screening for diabetic retinopathy: the utility of nonmydriatic retinal photography in Egyptian adults

BACKGROUND AND OBJECTIVE: Drug resistance has become a major cause of treatment failure in patients with acute leukemia. P-glycoprotein (Pgp), which is associated with the multidrug resistance (MDR) phenotype, has been reported to be an important predictor of treatment outcome. The aim of this study was to analyze the value of Pgp expression in bone marrow or peripheral blood as a predictor of the response to remission induction chemotherapy as well as the duration of remission in patients with de novo acute myeloid leukemia (AML). DESIGN AND METHODS: We examined the expression of Pgp in 82 patients with de novo AML using an immunocytochemical assay with the C219 monoclonal antibody. RESULTS: Twenty-seven of the 82 patients (33%) were C219-positive in from 1% to 100% of their cells. Thirteen cases (16%) showed a positive reaction in more than 50% of the leukemic cells. Only hyperleukocytosis was significantly associated with higher expression of Pgp. Although 8 of the 13 cases (62%) with more than 50% of cells having Pgp expression were CD34-positive, this association was not statistically significant. A univariate analysis of resistance to induction therapy showed a significantly higher resistance rate in patients with increased Pgp expression (P = 0.01) as well as in those patients with decreased reactivity to myeloperoxidase. The multivariate analysis revealed the independent prognostic value of Pgp expression. C219 reactivity did not have an influence on remission duration. INTERPRETATION AND CONCLUSIONS: Our data indicate that P-glycoprotein expression is a reliable marker of resistance to induction treatment in patients with de novo AML.     

Psychosocial changes following retirement

This study was designed to: (a) identify the perceptions of retirees about changes in their life patterns during retirement; (b) investigate the kinds of adjustment problems occurring in retirement as a basis for developing prevention oriented pre-retirement programs; and (c) identify extant factors which could demonstrate underlying themes relating to retirement adjustment. A 72-item, multiple response questionnaire was used to gather demographic data, information on use of time, pre-retirement planning, health problems, changing life patterns, and adjustment to retirement. It is the latter which is reported in these findings. The population included 1565 retirees from a designated company living in the south-eastern United States of America, with a response of 764 subjects (48.82%). Findings suggest the respondents were generally healthy and well adjusted; however, numerous adjustment problem areas were identified within the six life patterns. Additional factor analysis (principal components) demonstrated four factors of particular importance: satisfaction with retirement, retirement concerns, spousal relationships, and pre-retirement preparation outcomes.     

Synthesis of corneal keratan sulfate proteoglycans by bovine keratocytes in vitro

Keratan sulfate proteoglycans (KSPGs) are the major proteoglycans of the cornea and are secreted by keratocytes in the corneal stroma. Previous studies have been able to show only transient secretion of KSPG in cell culture. In this study, cultures of bovine keratocytes were found to secrete the three previously characterized KSPG proteins into culture medium. Reactivity with monoclonal antibody I22 demonstrated substitution of these proteins with keratan sulfate chains. KSPG constituted 15% of the proteoglycan metabolically labeled with [35S]sulfate in keratocyte culture medium. This labeled KSPG contained keratan sulfate chains of 4700 Da compared to 21,000 Da for bovine corneal keratan sulfate. Labeled keratan sulfate from cultures contained nonsulfated, monosulfated, and disulfated disaccharides that were released by digestion with endo-beta-galactosidase or keratanase II. Nonsulfated disaccharides were relatively more abundant in keratan sulfate from culture than in corneal keratan sulfate. These results show that cultured bovine keratocytes maintain the ability to express all three of the known KSPG proteins, modified with keratan sulfate chains and sulfated on both N-acetylglucosamine and galactose moieties. KSPG made in vitro differs from that found in vivo in the length and sulfation of its keratan sulfate chains. The availability of cell cultures secreting corneal keratan sulfate proteoglycans provides an opportunity to examine biosynthesis and control of this important class of molecules.     

Primary focal segmental glomerulosclerosis: clinical course and response to therapy

Primary focal segmental glomerulosclerosis (FSGS) is a lesion associated with a poor prognosis and results in end-stage renal disease after 5 to 10 years. Based on past experience, many nephrologists have considered primary FSGS a lesion that is steroid resistant and therefore are reluctant to offer steroids as treatment. Recent data, however, have demonstrated that patients with primary FSGS have a response to steroid therapy that is considerably better than had been described. Thus, it may be that nephrologists have been more "steroid reluctant" than the lesion is steroid resistant. To better understand this issue we review the clinical course and response to therapy in patients with primary FSGS.     

Net interaction between different forms of short-term synaptic plasticity and slow-IPSPs in the hippocampus and auditory cortex

Paired-pulse plasticity is typically used to study the mechanisms underlying synaptic transmission and modulation. An important question relates to whether, under physiological conditions in which various opposing synaptic properties are acting in parallel, the net effect is facilitatory or depressive, that is, whether cells further or closer to threshold. For example, does the net sum of paired-pulse facilitation (PPF) of excitatory postsynaptic potentials (EPSPs), paired-pulse depression (PPD) of inhibitory postsynaptic potentials (IPSPs), and the hyperpolarizing slow IPSP result in depression or facilitation? Here we examine how different time-dependent properties act in parallel and examine the contribution of gamma-aminobutyric acid-B (GABAB) receptors that mediate two opposing processes, the slow IPSP and PPD of the fast IPSP. Using intracellular recordings from rat CA3 hippocampal neurons and L-II/III auditory cortex neurons, we examined the postsynaptic responses to paired-pulse stimulation (with intervals between 50 and 400 ms) of the Schaffer collaterals and white matter, respectively. Changes in the amplitude, time-to-peak (TTP), and slope of each EPSP were analyzed before and after application of the GABAB antagonist CGP-55845. In both CA3 and L-II/III neurons the peak amplitude of the second EPSP was generally depressed (further from threshold) compared with the first at the longer intervals; however, these EPSPs were generally broader and exhibited a longer TTP that could result in facilitation by enhancing temporal summation. At the short intervals CA3 neurons exhibited facilitation of the peak EPSP amplitude in the absence and presence of CGP-55845. In contrast, on average L-II/III cells did not exhibit facilitation at any interval, in the absence or presence of CGP-55845. CGP-55845 generally "erased" short-term plasticity, equalizing the peak amplitude and TTP of the first and second EPSPs at longer intervals in the hippocampus and auditory cortex. These results show that it is necessary to consider all time-dependent properties to determine whether facilitation or depression will dominate under intact pharmacological conditions. Furthermore our results suggest that GABAB-dependent properties may be the major contributor to short-term plasticity on the time scale of a few hundred milliseconds and are consistent with the hypothesis that the balance of different time-dependent processes can modulate the state of networks in a complex manner and could contribute to the generation of temporally sensitive neural responses.     

A point of view: why point-of-care places are not free marketplaces

Current wisdom holds that health care is a business and "as such must abide by market principles." Most nurses are not well enough versed in economic theories to credibly critique health care delivery decisions based on economic theories. The relationship of market principles to health care realities is described in basic terms to encourage nurses to "optimize patient care and influence health care policy." Physicians, who control all access points to the health care system, have enjoyed a 40-year market dominance that is "rapidly being replaced by insurance companies and for-profit investors." Providers' decisions to treat or not to treat are strongly influenced by whether the patient is in a fee-for-service or capitated payment environment.     

Ristocetin- and thrombin-induced platelet aggregation at physiological shear rates: differential roles for GPIb and GPIIb-IIIa receptor

We recently reported that washed platelets (WP) activated with ADP and expressing surface-bound vWF aggregated in flow through small tubes or in a cylindrical couette device at physiological shear rates of G = 300 s(-1)-1000 s(-1) in the absence of exogenous ligands, with GPIb-vWF partially, and activated GPIIb-IIIa totally required for the aggregation. We have now extended these studies to aggregation of platelets "activated" with ristocetin or thrombin. Washed platelet suspensions with added soluble vWF and ristocetin (0.3-0.75 mg/ml), or activated with thrombin (0.01-0.5 U/ml) but no added ligand, were sheared in a coaxial cylinder device at uniform shear rate, G = 1000 s(-1). The collision capture efficiency (alphaG) with which small aggregates form (= experimental/calculated initial rates of aggregation) was correlated with vWF platelet binding assessed by flow cytometry. The vWF-GPIb interaction was exclusively able to support ristocetin-mediated shear aggregation of metabolically active platelets, with very few vWF monomer equivalents bound per platelet (representing < or = 10 molecules of 10 million Da) required to yield high capture efficiencies (alphaG = 0.38+/-.02; n = 11), suggesting rapid and stable bond formations between vWF and GPIb. However, platelet surface-expressed vWF, generated by addition of thrombin to washed platelets, was found to mediate platelet aggregation with alphaG = 0.08+/-.01 (n = 6), surprisingly comparable to that previously reported for WP and ADP activation. Blocking the GPIIb-Illa receptor decreased alphaG by 95+/-3% (n =3), while a monoclonal antibody to the vWF site on GPIb caused a 49+/-7% (n = 8) decrease in alphaG. The partial role for GPIb thus appears to reflect a facilitative function for increasing contact time between flowing platelets, and allowing engagement of the GPIIb-IIa receptor to yield stable attachment.     

Application of polymerase chain reaction for the correlation of Salmonella serovars recovered from greyhound feces with their diet

The polymerase chain reaction was employed to correlate Salmonella serovars isolated from fecal material of greyhounds suffering from gastroenteritis with those isolated from the diet fed to the greyhounds prior to onset of diarrhea. Kennels around the Abilene, Kansas, area were contacted and supplied with materials needed to collect a portion of the diet each day. With the onset of diarrhea, the kennels were instructed to ship the fecal material and diet from the previous 10 days to the laboratory for testing. Forty-one fecal samples and corresponding diets were screened for Salmonella, Clostridium perfringens, Campylobacter jejuni, Staphylococcus aureus, Staphylococcus intermedius, and pathogenic (piliated) Escherichia coli by direct culture using standard procedures. The fecal material was also screened for coronavirus and parvovirus using electron microscopy. Thirty-five "normal" fecal samples were screened for all of the above mentioned microorganisms as a control. In addition, the fecal material was screened for E. coli verotoxins I and II and clostridial enterotoxins. A total of 61 Salmonella isolates were recovered from the 41 samples of feces and diet submitted for testing; 31 were recovered from the feces and 30 from the diet. Four Salmonella isolates were recovered from the normal fecal samples. Results obtained by PCR, plasmid profiles, antigenic analysis, and antibiogram profiles indicated that 16 of the 31 isolates recovered from the fecal material were the same strain as that recovered from the diet.     

Diagnostic value of determining hemoglobin in cerebrospinal fluid in acute cerebral circulatory disorders

The results of hemoglobin determination in the CSF by the method of fluorescence microscopy in 195 patients speaks in favor of relative diagnostical importance of hemoglobin in the supra fall-out CSF for establishing the character of the stroke. The following circumstances testify to this fact: 1) in an artificial admixture of blood in the CSF in some cases there may be hemolysis of "passing" erythrocytes; 2) in a genuine admixture of blood, tests of hemoglobin in the centrifugate of the CSF may be negative since in some cases the transition of hemoglobin into bilirubin in the subarachmoid space occurs more rapidly than the hemolysis of erythrocytes. Thus, the hemoglobin does not accumulate in the liquid in quantities, sufficient enough to be measured by the existing methods; 3) in a large amount of artificial blood admixture, even without a hemolysis of "passing" erythrocytes the hemoglobin tests in the centrifugate of the CSF may be positive at the expense of hemoglobin of the blood plasma.     

From Laboratory Experiments to Design of a Conveyor-Belt Dryer via Mathematical Modeling

Abstract

A conveyor-belt dryer for picrite has been modeled mathematically in this work. The necessary parameters for the system of equations were obtained from regression analysis of thin-layer drying data. The convective drying experiments were carried out at temperatures of 40, 60, 80, and 100°C and air velocities of 0.5 and 1.5 m/sec. To analyze the drying behavior, the drying curves were fitted to different semi-theoretical drying kinetics models such as those of Lewis, Page, Henderson and Pabis, Wang and Singh, and the decay models. The decay function (for second order reactions) gives better results and describes the thin layer drying curves quite well. The effective diffusivity was also determined from the integrated Fick's second law equation and correlated with temperature using an Arrhenius-type model. External heat and mass transfer coefficients were refitted to the empirical correlation using dimensionless numbers (J _h , J _D  = m · Re ⁿ ) and their new coefficients were optimized as a function of temperature. The internal mass transfer coefficient was also correlated as a function of moisture content, air temperature, and velocity.