[Assessment of glomerular filtration rate in a hospital population. Comparison of two methods]

OBJECTIVES

This study was undertaken to assess the value of Cockroft-Gault Formula (FCG) in the patients of an Internal Medicine ward.

METHODS

FCG was compared with creatinine clearance (DC) adjusted for corporal area. Serum creatinine was measured after 24 h urine collection and 8 h fast. By the subtraction of FCG from DC, the variable difference (DIF) was calculated. FCG was calculated using total body weight (PT) and lean body weight (PS). All patients were included unless they had renal failure.

RESULTS

Renal function was calculated in 92 patients, 33 women and 59 men. Mean age was 60.8 +/- 17.9 (13-87). Mean FCG (64.7 +/- 27.4) and mean DC (68.4 +/- 32.6) were not significantly different and a correlation between them was found (r = 0.68; p < 0.001). Using PS to estimate FCG the correlation coefficient was increased to 0.75 (p < 0.001). DC and FCG using PT or PS correlated inversely with age (r = 0.59; r = 0.53; r = 0.66, respectively; p < 00.1). In a cluster analysis model we could find that for extremes of renal function FCG overestimated (DIF = -10.4 +/- 13.3) or underestimated (DIF = 29.8 +/- 29.7) DC. The main influence for the difference between the two methods was body weight (r = -0.69; p < 0.001). The distribution by diagnosis led to two classes of patients for whom DIF was significantly different (p < 0.02), and body weight was the main factor.

CONCLUSION

Cockroft-Gault formula, although correlating with creatinine clearance, over or underestimates creatinine clearance for extremes of renal function. Age and body weight were the main factors for the differences found between the two methods.

Long-term survival of free fat grafts in muscle: an experimental study in rats

In this study, we showed both macroscopically and microscopically the viability of the autotransplanted fat placed intramuscularly in long-term follow-up. The study was performed on 120 Wistar rats during a 12-month period. The fat grafts were obtained from either the inguinal region or preurinary bladder cavity. Rats were divided into six groups. In group 1, the fat was injected in thin rolls in the frontal subcutaneous layer. In group 2, the fat was injected in thin rolls in the gluteus superficialis, biceps femoris, gastrocnemius, and semitendinosus muscles. In group 3, 6 mm x 2 mm fat strips were placed subcutaneously in the frontal region. In group 4, the same dimension of fat strips were placed in the gluteus superficialis and biceps femoris muscles. In group 5, large cystic spaces of fat were injected subcutaneously in the frontal region, and in group 6, large cystic spaces of fat were injected intramuscularly. Rats at 3, 6, 9, and 12 months after fat grafting were sacrificed in order to carry out the macroscopic observations. The results showed clinical and microscopic success in groups 2 and 4, and problems and failure with the remaining groups.

The effect of salinity on the growth and carotenogenesis in two Chilean strains of Dunaliella salina Teodoresco

We studied the effect of salt concentration on the growth and carotenogenesis in two Chilean strains of Dunaliella salina, CONC-006 and CONC-007, cultivated in two media of different chemical composition J/l and PES, under controlled laboratory conditions. Growth rates, k (div day-1), intrinsic production rates of total carotenoids per unit time rcar (day-1), maximum levels of total carotenoids, K (mg l-1), and maximum production of total carotenoids per unit time, rK/4 (micrograms l-1 day-1) were estimated from growth and carotenogenesis data. The highest maximum productivity of total carotenoids was 978 micrograms l-1 day-1 obtained in CONC-007 at 25% NaCl, and the lowest 15 micrograms l-1 day-1, in CONC-006 at 30% NaCl, both growing in PES medium. CONC-007 showed the highest growth rates, 0.76 and 0.65 div day-1, at the lowest salt concentration (5%) in PES and J/1, respectively. On the contrary, the strain CONC-006 exhibited a different growth pattern in both media. Its maximum growth rate in J/1 was 0.37 div day-1 at 20% NaCl, and in PES, 0.53 div day-1 at 5% NaCl. According to these results, the best integration of growth and carotenogenesis in CONC-007 was obtained at 15% NaCl in J/1 from 10 to 25% NaCl in PES and in CONC-006, from 5 to 20% NaCl in J/1 and from 5 to 10% NaCl in PES.

Occupational allergic contact dermatitis in construction workers

We report the patch test results of 449 construction workers who came as patients to the Occupational Dermatology Service of the Instituto Nacional de Medicina y Seguridad del Trabajo in Madrid between 1989 and 1993. 90.8% of them were patch tested, because they had cutaneous lesions or a clinical history suggestive of occupational dermatitis. 65.5% (268) of those patch tested showed one or more reactions connected with their work. Chromate at 42.1% was the main allergen, followed by cobalt, 20.5%, nickel, 10%, and epoxy resin, 7.5%. 25.9% (106) of patients showed sensitization to rubber components, the majority at 23.7% to thiuram mix, with TETD being the main allergen.

Myoplasmic Ca2+ concentration during exertional rhabdomyolysis

Exertional rhabdomyolysis can destroy muscle but the pathophysiology is unknown. Using intracellular selective microelectrodes, we found that intracellular Ca2+ concentration ([Ca2+]i) was 1.27 (0.17) mumol/L (median and interquartile range) in skeletal-muscle biopsy specimens from patients with exertional rhabdomyolysis compared with 0.12 (0.01) mumol/L in controls. 3 days treatment with dantrolene, a drug that inhibits Ca2+ release from the sarcoplasmic reticulum, decreased [Ca2+]i to 0.22 (0.05) mumol/L and accelerated patients' recovery. This study demonstrated that exertional rhabdomyolysis is associated with elevated [Ca2+]i, and that dantrolene has a beneficial effect in this syndrome.

Dissociation between anti-infarct effect and anti-edema effect of ischemic preconditioning

This study tested the hypothesis that preconditioning, by reducing catabolite accumulation during ischemia, reduces osmotic swelling and myocardial necrosis during subsequent reperfusion. Farm pigs were randomly allocated to one of three groups of treatment: a control group undergoing a 48-min coronary occlusion (CO) of the middle left anterior descending artery, a preconditioned group (2 cycles of 5-min CO and 5-min reperfusion before the 48-min CO), or an intracoronary perfusion group receiving a substrate-free anoxic buffer perfusion into the area at risk between minutes 5 and 10 of the prolonged CO. Animals were killed after 30 min (n = 23) or 6 h (n = 31) of reperfusion. Compared with the control group, both ischemic preconditioning and washout of ischemic by-products by transient anoxic perfusion reduced myocardial edema after 30 min of reperfusion (P < 0.002) by 35 and 32%, respectively, but only ischemic preconditioning reduced final infarct size (by 55%, P < 0.006). Myocardial lactate content before reperfusion, measured in an additional series of 12 experiments, was reduced by 35% in animals receiving preconditioning or intracoronary perfusion. Thus ischemic preconditioning has a marked protective effect against reperfusion edema, and this effect can be explained by reduced catabolite accumulation during ischemia. However, there is no evidence from this study indicating that reduced catabolite accumulation and limited reperfusion edema explain the important anti-infarct effect of ischemic preconditioning.

Intracranial pressure dynamics in clinical practice: online PC-based ICP monitoring system

Correct patient management involves determining the exact point on the intracranial pressure/volume (P/V) curve that corresponds to the patient; this requires calculating intracranial elastance (IE). Intracranial pressure (ICP) monitoring systems should provide the necessary information for this purpose. An ICP monitoring unit is presented that acquires ICP, systemic arterial pressure (SAP) and airway pressure (AWP). The cerebral perfusion pressure (CPP) and the mean values and the peak-to-peak values of the two of them (ICPmean, SAPmean, ICPp-p, SAPp-p,) are calculated. Graphs display the temporal evolution (TE) of the ICP and SAP, as well as histograms of the ICP (%) and intracranial pulse amplitude (ICPAmP) with respect to the ICP or CPP during the preceding 3, 6, 12 or 24 h of monitoring. By digital filtering the ICP respiratory and cardiac components (RCICP, CCICP) are calculated. Finally, the pulse amplitudes (AmP) of the ICP, CCICP and RCICP are computed, as well as the average pulses per minute of SAP, CCICP, AWP and RCICP. Two off-line pulse-amplitude and pulse-morphology oriented toolkits display the afore-mentioned curves, histograms and average pulses per minute, and other additional ones, in order to achieve a deeper patient monitoring study.

Oral pharmacokinetics of carbamazepine in dogs from commercial tablets and a cyclodextrin complex

The extent of absorption of carbamazepine from a 2-hydroxypropyl-beta-cyclodextrin/carbamazepine complex was significantly greater and the rate of absorption was faster when compared with an immediate-release carbamazepine tablet in the dog. Six dogs were dosed orally in a two-way crossover study in which the tablet was compared with an equivalent dose of the complex in solution. The area under the curve of concentration versus time for the complex was 5.6 times greater than the tablet, whereas the mean time to reach maximum concentration for the tablet was 1.4 hours versus 0.5 hours for the complex. The complex, therefore, had a greater rate and extent of absorption. A rapidly acting and better absorbed carbamazepine product has the potential to decrease the daily dose of carbamazepine, increase its utility as emergency treatment of epileptic seizures, and provide an acceptable alternative dosage form in patients who are unable to swallow tablets.

An ODA-based coder/decoder for multimedia medical documents

This paper describes the prototype of a coder/decoder based on the Open Document Architecture (ODA) standard for management of medical documents, as well as the working environment in which it has been developed. The prototype has been assessed in an X-Windows-equipped workstation with a relational database containing patient folders (text and still images) from the departmental information system of the liver transplantation unit.

Digitization of medical documents: an X-Windows application for fast scanning

This paper deals with digitization, using a commercial scanner, of medical documents as still images for introduction into a computer-based Information System. Document management involves storing, editing and transmission. This task has usually been approached from the perspective of the difficulties posed by radiologic images because of their indisputable qualitative and quantitative significance. However, healthcare activities require the management of many other types of documents and involve the requirements of numerous users. One key to document management will be the availability of a digitizer to deal with the greatest possible number of different types of documents. This paper describes the relevant aspects of documents and the technical specifications that digitizers must fulfill. The concept of document type is introduced as the ideal set of digitizing parameters for a given document. The use of document type parameters can drastically reduce the time the user spends in scanning sessions. Presentation is made of an application based on Unix, X-Windows and OSF/Motif, with a GPIB interface, implemented around the document type concept. Finally, the results of the evaluation of the application are presented, focusing on the user interface, as well as on the viewing of color images in an X-Windows environment and the use of lossy algorithms in the compression of medical images.

A 40-kilodalton protein binds specifically to an upstream sequence element essential for muscle-specific transcription of the human myoglobin promoter

To define transcriptional control elements responsible for muscle-specific expression of the human myoglobin gene, we performed mutational analysis of upstream sequences (nucleotide positions -373 to +7 relative to the transcriptional start site) linked to a firefly luciferase gene. Transient expression assays in avian and mammalian cells indicated that a CCCACCCCC (CCAC box) sequence (-223 to -204) is necessary for muscle-specific transcription directed either by the native myoglobin promoter or by a heterologous minimal promoter linked to the myoglobin upstream enhancer region. A putative MEF2-like site (-160 to -169) was likewise necessary for full transcriptional activity in myotubes. Mutations within either of two CANNTG (E-box) motifs (-176 to -148) had only minimal effects on promoter function. We identified and partially purified from nuclear extracts a 40-kDa protein (CBF40) that binds specifically to oligonucleotides containing the CCAC box sequence. A mutation of the CCAC box that disrupted promoter function in vivo also impaired binding of CBF40 in vitro. These data suggest that cooperative interactions between CBF40 and other factors including MEF-2 are required for expression of the human myoglobin gene in skeletal muscle.

Dose proportionality of transdermal nitroglycerin

The FDA Cooperative Efficacy Study of transdermal nitroglycerin utilized a combination of marketed products over a wide dose range. Unfortunately, plasma nitroglycerin concentrations were not determined. The current study was conducted to assess plasma nitrate concentrations after transdermal doses of 15, 30, 60, and 105 mg/24 hr employing the FDA Cooperative Study design. Plasma concentrations of nitroglycerin, 1,3-glyceryl dinitrate, and 1,2-glyceryl dinitrate were determined during the 24 hr of application and for 1 hr after transdermal system removal. Dose proportionality was assessed after normalizing the data by theoretical dose. For nitroglycerin, dose-normalized AUC(0-infinity) and Cmax were higher for the 105 mg/24 hr dose than for the other doses. For the metabolites, 1,3-glyceryl dinitrate and 1,2-glyceryl dinitrate, there were no differences in dose-normalized AUC(0-infinity) and dose-normalized Cmax between the dose levels. No differences were seen in Tmax between the dose levels for all three species. Based on the dinitrate metabolites, dose proportionality was seen over the 15 to 105 mg/24 hr dose range. Nitroglycerin, however, was found to be linear only between 15 and 60 mg/24 hr.

Use of an ATP-supplemented medium for the conservation of human semen and the effect of caffeine on the motility of preserved sperm. Results in artificial insemination

Human semen can be preserved at 4 degrees C in an artificial medium containing 15% ATP-MgCl2 for up to 5 d. This method has been applied to samples from subjects with either normal or abnormal semen. After the conservation period the recovery of sperm motility observed was good when low doses of caffeine (3.5 or 7.0 mM) were added.

Role of atrial natriuretic peptide on calcium channel mechanisms involved in catecholamine release from bovine adrenal medulla

The role of the atrial natriuretic peptide on calcium channel mechanisms involved in catecholamine release was studied in the perfused bovine adrenal medulla. The atrial natriuretic peptide (1 nM and 10 nM) did not modify the spontaneous release of catecholamines. Ten nM of atrial natriuretic peptide decreased the output of catecholamines induced by acetylcholine, KCl-depolarizing solutions and angiotensin II. It was ineffective to modify the catecholamine release when calcium channels were blocked or in the presence of calcium-free media. Moreover, the deprivation of the ion calcium in the media decreased the catecholamine release induced by KCl to a lowest level, despite the presence of atrial natriuretic peptide in the perfusate. In conclusion, atrial natriuretic peptide inhibited the induced secretion of catecholamines in the bovine adrenal medulla and interfered as a partial blocker with calcium-dependent mechanisms.