Gastrointestinal complications of prescription and over-the-counter nonsteroidal anti-inflammatory drugs: a view from the ARAMIS database. Arthritis, Rheumatism, and Aging Medical Information System

More than 30 million people worldwide consume prescription nonsteroidal anti-inflammatory drugs (NSAIDs) on a daily basis. Gastrointestinal (GI) toxicity owing to the use of NSAIDs is a well-recognized clinical problem, with approximately 25% of all reported adverse drug reactions being attributed to prescription NSAID use. In addition to prescription NSAIDs, the use of over-the-counter (OTC) formulations of these products is common. Although it has been suggested that OTC doses of NSAIDs may not lead to significant GI toxicity, the data confirming this have been lacking. Data on the GI risks of OTC doses of aspirin, ibuprofen, naproxen, paracetamol, and no drug from 4164 consecutively diagnosed patients with rheumatoid arthritis from eight ARAMIS (Arthritis, Rheumatism, and Aging Medical Information System) centers in North America are presented. Serious GI events were defined as GI bleeds and other clinically significant GI events requiring hospitalization. Relative risks were standardized for potential demographic confounders using Cox proportional hazard models. Although the relative risk of OTC doses of NSAIDs (3 to 4) is less than the previously published risk of prescription doses (6 to 7), it remains clinically significant and a matter of serious concern because of the widespread use of these medications and an underappreciation of the true risk. Paracetamol was not associated with increased risk of GI complications and should be considered first-line therapy.

Dosage of once-daily gentamicin in spinal cord injury patients

INTRODUCTION

In patients with spinal cord injury (SCI), serum creatinine does not accurately reflect the level of renal function. Therefore, in SCI patients, the dose of potentially nephrotoxic drugs should be adjusted on an individual basis from the estimated creatinine clearance.

CASE REPORT

A 41-year-old male with tetraplegia due to cervical spinal cord injury underwent extended pyelolithotomy for staghorn calculus in the right kidney. The blood urea level was 9.9 mmol/l; creatinine was 112 umol/l (reference range: 0-135). We were conscious of this patient's renal disease, and therefore, administered only 3 mg/kg of gentamicin (240 mg) instead of the standard dose of 5 mg/kg body weight. Despite taking this precaution, the gentamicin level measured 22.5 h after the initial dose, was in the potentially toxic range 3.3 mg/l.

CONCLUSION

We recommend that even the first dose of gentamicin in the once-daily regimen, which is 5 mg/kg, should be individualised in SCI patients based on age, sex, weight, height, level of spinal cord injury, and renal function.

Enlarging single CT lesions can also spontaneously resolve

Computed tomography in two patients, aged 9 and 14 years, with history of focal seizures, revealed single, small, enhancing CT lesions. These patients were treated with albendazole and anticonvulsants. Follow-up CT scans revealed an increase in the size of the solitary lesions. They were managed conservatively and further follow-up CT scans revealed complete resolution of the lesions. The report suggests that some enlarging CT lesions may also spontaneously resolve. The most likely cause of the enlarging lesions was albendazole therapy.

Influence of the proto-oncogene c-fos on cisplatin sensitivity

Cisplatin resistance has been associated with overexpression of the c-fos gene in a human ovarian carcinoma cell line. To determine whether the correlation between c-fos overexpression and cisplatin resistance was limited to this cell line or was a more generalized phenomenon, we investigated cisplatin sensitivity in rat fibroblast cells that overexpressed the c-fos gene. The cisplatin Ic50 values for two different c-fos transfectants, CMVc-fos and L1-3c-fos, were 7.6 +/- 0.8 and 5.6 +/- 1.0 microM, respectively, whereas the cisplatin Ic50 value for the parental line, 208F, was 2.4 +/- 0.1 microM. This represented a 3.2- and 2.3-fold resistance to cisplatin for CMVc-fos and L1-3c-fos cells, respectively. The correlation between c-fos expression and cisplatin resistance also was examined in a human ovarian carcinoma cell line, 2008, and its cisplatin-resistant variant, C13*. Expression of c-fos was elevated slightly at both the mRNA and protein levels in the C13* cells compared with 2008 cells, and c-Fos protein levels were induced in C13* cells following cisplatin treatment. In addition, it was observed that C13* cells were significantly more sensitive than 2008 cells to a c-fos antisense oligonucleotide. The Ic50 values for the c-fos antisense oligonucleotide were 19.9 +/- 5.0 pmol for C13* cells and 58.1 +/- 6.0 pmol for 2008 cells (P = 0.0012). Furthermore, combinations of c-fos antisense and cisplatin reduced the amount of cisplatin required to kill 50% of the C13* cells, although the interaction was not synergistic. These results suggest that expression of the c-fos gene can influence cisplatin sensitivity, and that c-fos antisense oligonucleotide based therapy may be effective at killing parental and cisplatin-resistant ovarian carcinoma cells, either alone or in combination with cisplatin.

Role of selective intra-operative cholangiography during cholecystectomy

BACKGROUND

The use of routine intra-operative cholangiography (IOC) remains controversial. This prospective study was carried out to determine whether to perform selective or routine IOC in patients undergoing cholecystectomy for gallstones.

METHODS

All consecutive patients undergoing open cholecystectomy over a 16-month period were included in the present study. They were divided into two groups based on the absence (n = 79) or presence (n = 55) of indicators of choledocholithiasis. All patients were subjected to cholangiography. Each indicator, subsets of indicators and all indicators combined were evaluated for their ability to predict choledocholithiasis.

RESULTS

There would be only two missed stones (1.5%) if selective cholangiography was to be practised. Intra-operative cholangiography had a positive predictive value of 100%. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of all the indicators combined were 93.5%, 84.6%, 74.5%, 97.5% and 88.0%, respectively. The best indicators in each subset were jaundice, common bile duct diameter as assessed by ultrasonography, and a palpable stone during surgery with NPV of 82.7%, 91.1% and 96.8%, respectively.

CONCLUSION

Routine IOC during cholecystectomy is not essential for the prevention of retained stones. A combination of the various indicators of choledocholithiasis can be used to select patients for cholangiography.

The role of the p53 tumor suppressor in the response of human cells to photofrin-mediated photodynamic therapy

Although there is evidence that the p53 tumor suppressor plays a role in the response of some human cells to chemotherapy and radiation therapy, its role in the response of human cells to photodynamic therapy (PDT) is less clear. In order to examine the role of p53 in cellular sensitivity to PDT, we have examined the clonogenic survival of normal human fibroblasts that express wild-type p53 and immortalized Li-Fraumeni syndrome (LFS) cells that express only mutant p53, following Photofrin-mediated PDT. The LFS cells were found to be more resistant to PDT compared to normal human fibroblasts. The D37 (LFS cells)/D37 (normal human fibroblasts) was 2.8 +/- 0.3 for seven independent experiments. Although the uptake of Photofrin per cell was 1.6 +/- 0.1-fold greater in normal human fibroblast cells compared to that in LFS cells over the range of Photofrin concentrations employed, PDT treatment at equivalent cellular Photofrin levels also demonstrated an increased resistance for LFS cells compared to normal human fibroblasts. Furthermore, adenovirus-mediated transfer and expression of wild-type p53 in LFS cells resulted in an increased sensitivity to PDT but no change in the uptake of Photofrin per cell. These results suggest a role for p53 in the response of human cells to PDT. Although normal human fibroblasts displayed increased levels of p53 following PDT, we did not detect apoptosis or any marked alteration in the cell cycle of GM38 cells, despite a marked loss of cell viability. In contrast, LFS cells exhibited a prolonged accumulation of cells in G2 phase and underwent apoptosis following PDT at equivalent Photofrin levels. The number of apoptotic LFS cells increased with time after PDT and correlated with the loss of cell viability. A p53-independent induction of apoptosis appears to be an important mechanism contributing to loss of clonogenic survival after PDT in LFS cells, whereas the induction of apoptosis does not appear to be an important mechanism leading to loss of cell survival in the more sensitive normal human fibroblasts following PDT at equivalent cellular Photofrin levels.

Development of a Spanish (Castillian) version of the Childhood Health Assessment Questionnaire. Measurement of health status in children with juvenile chronic arthritis

OBJECTIVE

To demonstrate that the Spanish (Castillian) version of the Childhood Health Assessment Questionnaire (cHAQ-S) is a valid and reliable instrument for measuring the health status of children with juvenile chronic (or rheumatoid) arthritis (JCA) and is sensitive to change.

METHODS

A conceptual translation of the original questionnaire into Spanish and two back-translations were performed. The cHAQ-S was completed by the parents of young children (aged 1 to 19 years) affected by JCA, and additionally by those children aged over 9. A second cHAQ-S was administered at least 15 months after the first one.

RESULTS

The cHAQ-S was administered to 79 patients of patients affected by JCA. The test-retest reliability was evaluated among 16 patients, and no significant differences between the first and second administration were found (0.88 versus 0.84; p > 0.6; intraclass correlation coefficient R = 0.94). The Cronbach's alpha coefficient was 0.948, indicating an excellent internal reliability with a mean correlation between the different components of the questionnaire varying from 0.3557 to 0.7831. For the between-observer reliability, an intraclass correlation coefficient of 0.96 was obtained. Correlations between DI (Disability Index) and several measures of disease activity were all statistically significant (Spearman's R ranged from 0.42 to 0.87; p < 0.005). Patients who improved showed similar improvement in the DI (p = 0.015), while patients who worsened showed a worsening of the DI (p = 0.1) and patients whose condition was stable showed no change in DI (p = 0.6).

CONCLUSION

The cHAQ-S is a feasible, reliable and valid instrument for the determination of the health status of Spanish children suffering from JCA. It is also sensitive to changes in the child's health status.

Detection of salicylate and its hydroxylated adduct 2,3-dihydroxybenzoic acid in glutamate neurotoxicity and the effects of verapamil and ryanodine in rats

It has been suggested that salicylate hydroxylation can be used to detect hydroxyl radical formation in vivo. In the present study we investigated the effects of verapamil and or ryanodine on salicylate (SA) and its hydroxylated adduct; 2,3-dihydroxybenzoic acid (2,3-DHBA) levels in glutamate induced neurotoxicity of whole rat brains. To detect SA and 2,3-DHBA, an HPLC-EC/UV method was used. Retention time was found to be 3.9 min for 2,3-DHBA and 12.0 min for SA. Verapamil at 10(-5) and 10(-7) and ryanodine at 10(-5) M concentrations were found to have a significant decreasing effect on this degradation induced by glutamate. This was the highest dose for ryanodine tested. As an L-type voltage dependent calcium channel blocker, verapamil was found ineffective at 10(-4), 10(-6) and 10(-8) M concentrations. Surprisingly, none of the combined application groups (verapamil + ryanodine) was found effective on SA hydroxylation. As a result, ryanodine was effective only at the highest dose, while verapamil exerts its effect in a dose dependent fashion as reported before in the literature.

The cost-effectiveness of different management strategies for type I diabetes: a Swiss perspective

AIMS/HYPOTHESIS

A computer model was developed to determine the health outcomes and economic consequences of different combinations of diabetes interventions in newly diagnosed patients with Type I (insulin-dependent) diabetes in Switzerland.

METHODS

We modelled seven complications of diabetes: hypoglycaemia, ketoacidosis, acute myocardial infarction, stroke, lower extremity amputation, nephropathy, and retinopathy. Transition probabilities and costs were taken from published literature. The Swiss health insurance payer perspective was taken. Various combinations of diabetes management strategies, including intensive or conventional insulin therapy and screening and treatment strategies for renal and eye disease were defined. Life expectancy, cumulative incidences of complications, and mean expected total lifetime costs per patient were calculated under six different management strategies. Incremental cost-effectiveness ratios were calculated in terms of costs per life-year gained compared with conventional insulin therapy alone.

RESULTS

The addition of screening for microalbuminuria and retinopathy followed by appropriate treatment, if detected, were cost saving, with reduction in cumulative incidence of end stage renal disease and blindness respectively, and, in the case of microalbulminuria screening and treatment, an improvement in life expectancy. Intensive therapy improved life expectancy but increased total lifetime costs.

CONCLUSION/INTERPRETATION

Optimal management of Type I diabetic patients, including secondary and tertiary prevention, leads to reduced complications and improved life expectancy, with the increased costs of prevention offset to varying degrees by cost savings due to complications avoided.

Cutaneous sarcoidosis without systemic involvement

A 49-year -old woman presenting with features of cutaneous sarcoidosis without any evidence of systemic involvement is reported.

Species-dependent pharmacological properties of the melanocortin-5 receptor

The genes encoding the melanocortin-3 receptor and melanocortin-5 receptor have been cloned from rhesus monkey. Heterologous expression in CHO cells indicated species dependent in vitro pharmacological properties for the human and rhesus melanocortin-5 receptors. Several peptides including NDP-alpha-MSH, alpha-MSH, MT-II and ACTH1-24 are more potent at the rhesus melanocortin-5 receptor than the human melanocortin-5 receptor by more than 10-fold. In contrast, we found no species difference in pharmacological properties between the human and rhesus melanocortin-3 receptors. Such a species-dependent pharmacological difference for melanocortin-5 receptor appears to be an exception compared to other G protein-coupled receptors from human and rhesus monkey.

Neuromuscular transmission failure due to common krait (Bungarus caeruleus) envenomation

Neurophysiological studies were performed in 12 patients with neuromuscular paralysis due to envenomation by the common krait (Bungarus caeruleus). All patients presented with an acute, reversible, oculofaciobulbar paresis. In addition, 7 patients had weakness of the limb muscles and 4 required assisted mechanical ventilation. Neurophysiological abnormalities included: (1) a reduction in the amplitude of the median-elicited compound muscle action potential (CMAP) in 4 patients; and (2) a decremental response (>10%) to 3-Hz repetitive nerve stimulation (RNS) in 4 patients. With 1 exception, these abnormalities were noted only in clinically weak muscles. The administration of edrophonium to 6 patients produced an insignificant increase in CMAP amplitudes as well as partial (not significant) improvement in the decremental response to 3-Hz RNS. Neurophysiological studies were performed in 2 patients before and after the administration of 20 mL of polyvalent antivenom. A decrease in amplitude of the median-elicited CMAP amplitude occurred after the administration of antivenom. In 1 patient, administered 100 mL of antivenom, the median-elicited CMAP amplitude increased and the decrement to 3-Hz RNS decreased. Neurophysiological studies can provide useful information regarding the nature, severity, and therapy of the neuroparalytic syndrome of krait envenomation.

Role of computed tomography in spinal trauma

Twenty patients admitted for spinal trauma were studied with computed tomography (CT) scan. All the patients had initial routine plain radiographs in the anteroposterior and lateral views. Ten patients sustained injury due to fall from height, 7 suffered road side accident, 2 had injury due to fall of weight on back and one suffered due to slip on floor. Twelve patients had injury at multiple levels. Twenty-four vertebral bodies were involved in 20 patients, 10 had fracture of posterior elements only. Neurological deficit occurred in 16 patients. CT scan provided more information than plain radiography, which missed vertebral body fracture in 2 out of 24 instances and spinal canal compromise in 7 out of 12 patients. CT scan detected posterior element injuries better and in greater detail in all cases.

Immunohistochemical study of parathyroid hormone-related protein in vesical transitional epithelium of patients with spinal cord injury

INTRODUCTION

Parathyroid hormone-related protein (PTHrP), in addition to the well-established role in endochrondral bone development, is believed to be an important mediator of cellular growth and differentiation in a number of non-bony tissues.

OBJECTIVES

To compare the immunohistochemical staining of vesical transitional epithelium to antibodies raised to synthetic peptides of PTHrP composed of amino acid sequences 43 - 52 and 127 - 138 in patients with spinal cord injury (SCI) and neuropathic bladder (n=14), and control patients with intact neuraxis and no history of bladder cancer (n=10).

SETTING

Male SCI patients registered with Regional Spinal Injuries Centre, Southport, England.

INTERVENTION

Endoscopic cold cup biopsy from the trigone of the urinary bladder was taken from patients with SCI while they were undergoing a therapeutic procedure in the urinary bladder. The control samples of bladder biopsies were taken from the archives of the Department of Histopathology, District General Hospital, Southport. Immunohistochemistry was performed using rabbit antibodies raised against synthetic peptides of human PTHrP (43 - 52) and PTHrP (127 - 138). The biopsies were examined for immunostaining of transitional epithelium.

RESULTS

Of the 14 biopsies of SCI patients, positive immunostaining using antibodies to both the PTHrP peptides was found in four cases; five biopsies showed positive immunostaining only to anti-PTHrP (43 - 52); and five biopsies showed no immunostaining with either of the PTHrP peptides. In contrast, transitional epithelium in the biopsy specimens of ten control subjects with no history of bladder cancer showed no immunostaining with either of the PTHrP peptides.

CONCLUSION

This study revealed that the transitional epithelium of neuropathic urinary bladder exhibits increased predilection for positive immunohistochemical staining for PTHrP (43 - 52), and to a lesser extent, to PTHrP (127 - 138), as compared to the vesical transitional epithelium of able bodied individuals with no history of vesical malignancy. The possible role of PTHrP in the cellular differentiation of urothelium of neuropathic bladder, and thereby, in the pathogenesis of cystitis in SCI patients, needs to be explored.

Intra-specific and inter-specific conservation of mating-type genes from the discomycete plant-pathogenic fungi Pyrenopeziza brassicae and Tapesia yallundae

In previous work, four genes involved in mating-type determination were cloned from reference strains of Pyrenopeziza brassicae; three genes, PAD1, PMT1, and PHB1 (re-named henceforth as MAT-1-1, MAT-1-4, and MAT1-3, respectively), are encoded by the MAT-1 idiomorph, and one gene, PHB2 (re-named MAT-2), by the corresponding MAT-2 idiomorph. To assess MAT gene organisation within field-populations of P. brassicae, 30 field-isolates of both mating-types from different geographical locations were analysed by PCR using primers designed for the MAT genes of P. brassicae. The results indicate that mating-type gene structure and organisation within these isolates is conserved and is consistent with the mating-type designations established by crossing experiments. The four P. brassicae MAT genes were then used as probes against gel blots of the genomic DNA of a discomycete Tapesia yallundae from the same family (Dermateaceae, order Helotiales) and one, Ascobolus stercorarius, from a distantly related family (Ascobolaceae, order Pezizales), in order to determine whether P. brassicae MAT-gene homologs were present. MAT-specific hybridisation signals were obtained with T. yallundae using all four probes. In particular, MAT-1 DNA of T. yallundae gave a strongly hybridising signal with MAT-1-4 (PMT1), a putative metallothionein gene found in the P. brassicae MAT-1 idiomorph but not in any other MAT idiomorph examined to-date. No MAT-specific hybridisation was obtained with A. stercorarius. A fragment of the MAT-2 gene of T. yallundae was obtained by PCR using degenerate primers designed to amplify the high-mobility group (HMG) domain present in other ascomycete MAT genes. Sequencing of this PCR product revealed similarities to MAT HMG domains from other ascomycetes with the greatest degree of similarity exhibited with P. brassicae. The T. yallundae HMG-DNA sequence was shown to co-segregate with mating type (MAT-2) in progeny from a sexual cross.

Laser photofragmentation-fragment detection and pyrolysis-laser-induced fluorescence studies on energetic materials

Trace concentrations of energetic materials such as 2, 4, 6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and hexahydro-1, 3, 5-trinitro-s-triazine (RDX) are detected by laser photofragmentation-fragment detection (PF-FD) spectrometry. In this technique, a single laser operating near 227 nm photofragments the parent molecule and facilitates the detection of the characteristic NO fragment by means of its A (2)Sigma(+)-X (2)Sigma (0, 0) transitions near 227 nm. Fragment detection is accomplished by resonance-enhanced multiphoton ionization with miniature electrodes and by laser-induced fluorescence (LIF) with a photodetector. Experiments are also conducted in the visible region by use of 453.85-nm radiation for photofragmentation and fragment detection. Sand samples contaminated with PETN and RDX are analyzed by a pyrolysis-LIF technique, which involves pyrolysis of the energetic material with subsequent detection of the pyrolysis products NO and NO(2) by LIF and PF-LIF, respectively, near 227 nm. The application of these techniques to the trace analysis of TNT, PETN, and RDX at ambient pressure in room air is demonstrated with limits of detection (signal-to-noise ratio, 3) in the low parts-in-10(9) to parts-in-10(6) range for a 20-s integration time and 10-120 microJ of laser energy at 226.8 nm and approximately 5 mJ at 453.85 nm. An increase in detection sensitivity is projected with an increase in laser energy and an improved system design. The analytical merits of these techniques are discussed and compared with those of other laser-based techniques.

Expression of metallothionein and nuclear size in discrimination of malignancy in mucinous ovarian tumors

Metallothioneins (MTs) are low molecular weight proteins that control cell proliferation via their metalloregulatory function. Several studies in various tumors have shown their influence in determining response to chemotherapy and prognosis. Because there has been no such study pertaining to ovarian tumors, we investigated MT expression and nuclear size in mucinous ovarian neoplasms (12 benign, 6 borderline, and 8 malignant). The percentage of MT-positive stained cells was significantly higher in the borderline than in the benign tumors, but lower than in the malignant tumors. Single layers of cells in the borderline tumors showed mild immunostaining in 50% of the cells and moderate staining in the remaining 50%, while 83.3% of cells within multilayered epithelium showed moderate to strong immunostaining. In the carcinomas, 87.5% of tumors showed moderate to strong staining in single-layered epithelium and moderate to strong staining of all the cells in multilayered epithelium. Morphometry measurements showed that the mean nuclear area of cells in the carcinomas was significantly larger than in the borderline or benign tumors. The nuclear area of cells in the carcinomas with early recurrence or metastasis was also significantly larger than in carcinomas without recurrence or metastasis. It is concluded that MT protein expression and nuclear size are possible markers for the evaluation of the progression of malignancy in mucinous ovarian tumors.

Utility of HemoCue in estimation of hemoglobin against standard blood cell counter method

INTRODUCTION

There are various methods which have been recommended for haemoglobin (Hb) estimation for assessment of anaemia. Each method has it's advantages and limitations.

OBJECTIVE

The present study was conducted to assess the utility of HemoCue, a recent method, in assessment of haemoglobin against the standard blood cell counter (BCC) method.

METHODOLOGY

Eighty five venous blood samples were collected, Hb was assessed in each by utilising the HemoCue and BCC methods. The results were compared utilising the standard statistical methods.

RESULTS

The HemoCue provided consistently higher value in comparison to BCC by a margin of 0.5 g/dl. It is known that the correlation coefficient is independent of change of origin but mean gets affected. Therefore, we can subtract 0.5 g/dl from the Hb estimates achieved by HemoCue through which all conditions regarding better agreement between both methods get satisfied. The two assays correlated well.

CONCLUSION

The HemoCue method was found more rapid and easy in assessment of total hemoglobin as compared to blood cell counter method with an adjustment of 0.5 per dl.

Coronary artery to pulmonary artery collaterals after heart transplantation

Collaterals are described between coronary and pulmonary arteries after orthotopic heart transplantation. It is likely the collaterals developed as a result of adhesions in the pericardial space. This is a previously unrecognized complication of heart transplantation with potential clinical implications, as coronary to extracardiac artery collaterals have been shown to cause myocardial ischemia.

Studies on energetic compounds. Part XI: preparation and thermolysis of polynitro organic compounds

The thermolysis of high energetic polynitro organic compounds has been reviewed in the present communication.

Regulation of prostate cancer cell division by glucose

Previous studies have shown that rapid cell proliferation is associated with elevated glucose consumption. However, those studies did not establish whether glucose is required for prostate cancer cell proliferation or define the molecular mechanisms by which glucose regulates cell division. We addressed these issues by studying two metastatic human prostate cancer cell lines: DU145, which is androgen independent and highly proliferative; and LNCaP, which is androgen dependent and relatively slow growing. We found that proliferation of DU145 cells was significantly inhibited by reduction of glucose in the medium to 0.5 g/L, which is half the physiologic concentration, whereas LNCaP cells grew at control rates even in the presence of only 0.05 g/L glucose. Glucose deprivation of DU145 cells caused a 90% reduction in DNA synthesis; a 10-20-fold reduction in cyclins D and E and CDK4 levels; and cell cycle arrest in G0-G1. However, glucose deprivation did not cause global inhibition of protein synthesis, since mutant p53 levels increased in glucose-deprived DU145 cells. This observed increase in mutant p53 levels was not associated with a rise in p21 levels. Glucose deprivation of DU145 cells also led to apparent dephosphorylation of mutant retinoblastoma (RB) protein. We conclude that: 1) high levels of glucose consumption are required for rapid proliferation of androgen-independent prostate cancer cells, 2) glucose may not be required for slow growth of androgen-dependent prostate cancer cells, and 3) glucose promotes passage of cells through early G1 by increasing the expression of several key cell cycle regulatory proteins that normally inhibit RB function.