Nitrendipine and enalapril in the treatment of diabetic hypertensive patients with microalbuminuria

A trial to study the efficacy, safety and tolerability of nitrendipine and enalapril in the treatment of diabetic hypertensive patients with microalbuminuria (MA) was performed to compare the effects of both drugs in the prevention of the renal impairment. Twenty-eight valid patients [13 with nitrendipine (N) and 15 with enalapril (E) with NIDDM, hypertension (diastolic blood pressure between 90 to 114 mm Hg) and MA (urinary albumin between 30 to 300 mg/24 hr) were recruited in a double blind, randomized trial. Following a placebo run-in period of two to four weeks, all eligible patients were randomly allocated to either N or E treatment. Treatment lasted six months, with two different visits at three and six months in which blood pressure (BP), heart rate (HR), renal function and MA were measured. No statistically significant differences on BP and metabolic parameters were found between both treatment groups. The geometric mean of final glomerular filtration rate (GFR) in the N group was 34.5% higher than in the E group, while the reduction on MA was most important in the E group. Eleven patients reported adverse events (AEs) and there were four dropouts, three of them due to AEs. We conclude that both treatments are a good choice for treating diabetic hypertensive patients with early altered renal function, as they reduce BP without altering metabolic parameters, increase GFR and reduce MA with a low frequency of AEs.

Cardiovascular and respiratory adjustments in normal volunteers during modified exercise tests in comparison to standard exercise tests

Sixteen normal, non-smoking first year medical students underwent four standard exercise tests, while cardiovascular (heart rate and blood pressure) and pulmonary (respiratory rate, tidal volume and oxygen consumption) adjustments were being monitored. Maximal exercise level for all tests were defined following the Jones scale. No variation was noted in respiratory rate among the four exercise tests. The cycle ergometry (CE), hand ergometry (HE), and treadmill (TM) exercise tests produced progressive increases of the various parameters as expected, although target maximal heart rates were not reached in most cases secondary to muscle fatigue. The step test (ST) approximated the physiological parameter changes noted in these three tests during the early stages of exercise, but levelled off after 3 minutes, probably due to lack of incremental load. The ST took the longest time to reach maximal level of exercise parameters, and recorded the lowest tidal volume increase. The same subjects underwent a modified step test (MST1) by adding 1 kg sandbags every 3 min to backpacks worn by the subjects, to provide incremental load. This modification provided a slight increase in the parameters measured, but still plateaued after 3 min. Another set of 18 normal, non-smoking medical students underwent bicycle ergometry and two other modified exercise tests. The modified step test two (MST2) was similar to our initial MST1, except that the sandbags added every 3 min were not fixed at 1 kg but were also incremental (1, 2, 3 and 4 kg). The other test (Ramp test or RT) required the subjects to walk up and down a ramp, which entailed not only the addition of incremental weights of sandbags every 3 min, but also increasing the elevation of the ramp at each stage. Data analysis showed that these two tests showed almost similar changes in cardiovascular and respiratory adjustments in the subjects, compared to the standard bicycle ergometry. These pilot studies showed that low-cost modified step tests may be utilized to approximate the expensive standard treadmill and bicycle exercise tests. More studies on larger populations have to be done to validate these results.

Effects of preweaning sensorimotor stimulation on behavioral and neuronal development in motor and visual cortex of the rat

The present study investigates the effects of early sensorimotor stimulation on behavioral and neuronal cytodifferentiation in motor and visual cortex of lactating rats. Seventy-two male and female Sprague-Dawley albino rats were systematically submitted to environmental stimulation during the early postnatal period (postnatal days 5-21). On postnatal day 22, four behavioral tests were performed (open field, narrow path crossing, hind limb support and ascending on a rope). In order to evaluate dynamic neuronal changes induced by sensorimotor enrichment, brains were stained through the Golgi-Cox-Sholl method. Morphometric studies were carried out in pyramidal neurons located in motor and visual cortical layers II and III, by measuring their basal dendritic length and branching. Further, wide cortical field studies were performed with the aim of evaluating the degree of development reached by clusters of pyramidal cells. The results indicate that sensorimotor stimulation carried out during the suckling period produced a significant increase in neuronal cytodifferentiation as observed in single cell studies. However, collective neuronal evaluations yielded less significant results. Consistently, rats exposed to enriched environments showed a better performance in behavioral adaptive responses.

Effects of preweaning environmental stimulation on neuronal and behavioral impairment produced by undernutrition

The present study investigates the effects of sensorimotor stimulation on the basal dendrogenesis of superficial cerebrocortical neurons and the accomplishment in the associated exploratory behavior in rats simultaneously exposed to nutritional deprivation. Sprague-Dawley albino rats were submitted to nutritional-environmental influences from birth to the 21st postnatal day. Exploratory behavior was assessed by the evaluation of locomotor activity in the open-field apparatus. In order to evaluate changes in neuronal morphology induced by nutritional-environmental variables, brains were stained according to the Golgi-Cox-Sholl procedure. Dendritic development was assessed under camera lucida by measuring basal dendritic branching of layer II and III pyramidal neurons, located in the dorsomedial region of the visual cortex of the rat. Morphometrical analysis revealed that both basal dendritic length and branching were significantly reduced by undernutrition. In contrast, environmental stimulation during the suckling period compensated for the neuronal impairment produced by protein-calorie deprivation. An improvement was also observed in exploratory behavior although to a lesser degree, as shown by the open field test data. In conclusion, the present results indicate that sensorimotor stimulation applied during the period of fastest rate of cortical cytodifferentiation compensates for neuronal and behavioral impairment produced by undernutrition.

[The validity of the separate determination of total cholesterol in the primary prevention of coronary risk]

BACKGROUND

The aim of this study was to validate total cholesterol (TC) determination in the primary prevention of coronary risk and evaluate the prevalence of low HDL cholesterol (HDL-C) levels at the different TC cut-off points to thereby determine the TC level at which HDL-C determination is of interest.

METHODS

The atherogenic index was used as the reference method in TC evaluation with the values of low HDL-C levels being evaluated at the following TC cut-off points: 160, 180, 200, 220, 240, 250, and 300 mg/dl (4.44; 4.66; 5.18; 5.70; 6.22; 6.48; 7.77 mmol/l). According to the results of the Framingham study the atherogenic index or the existence of low HDL-C levels were considered as abnormal. The sample included 4,162 workers from the province of Alicante (Spain) selected by consecutive sampling and opportunistic search in January and February, 1993. Validity was calculated with confidence interval of 95%.

RESULTS

The atherogenic index was high in 43.7% of the sample, ranging from 6% in the population with TC lower than 160 mg/dl (4.14 mmol/l) to 76.4% in those oscillating between 250-299 mg/dl (6.48-7.76 mmol/l). Low HDL-C levels were detected in 20.1% with a prevalence ranging from 38.8% in those with a TC of less than 160 mg/dl (4.14 mmol/l) to 11.9% in those with TC > or = 250 mg/dl (> or = 6.48 mmol/l). The cut-off points for low TC had high sensitivity (S) and low specificity (SP) (160 mg/dl [4.14 mmol/l]: S = 91.1%, SP = 11.5%; 180 mg/dl [4.66 mmol/l]: S = 95.2%, SP = 30.2%). The highest TC points presented very low S and very high SP (250 mg/dl [6.48 mmol/l]: S = 46.3%, SP = 87.7%; 300 mg/dl [6.48 mmol/l]: S = 7.4%, SP = 97%).

CONCLUSIONS

The HDL-cholesterol should be determined in people with a total cholesterol of less than 200 mg/dl (5.18 mmol/l) since, in this group there is an important percentage of individuals with an altered atherogenic index and low HDL-C levels.

Effects of sensitization on vasoactive intestinal polypeptide-induced relaxation and its concentration and binding in guinea-pig airways

We investigated the relaxant effect of vasoactive intestinal polypeptide (VIP) in trachea and lung parenchyma from normal and sensitized guinea-pigs. A technique by which drug access was restricted to either the mucosal or the adventitial surface of tracheal rings was used. In intact trachea, concentration-response curves for VIP entering from the mucosal surface (pD2 = 6.61 +/- 0.06) were displaced to the right compared with those for adventitial entry (pD2 = 6.78 +/- 0.04). Epithelium removal produced a leftward shift (approximately 2.8-fold) in the mucosal VIP concentration-response curve. Sensitization did not alter the responsiveness (maximal effect) or sensitivity (pD2 values) of tracheal rings to VIP irrespective of the surface of drug entry and of the absence or presence of epithelium. VIP-induced relaxation of normal and sensitized lung strips was also similar. Sensitization resulted in a significant decrease in tracheal VIP content (from 2.16 +/- 0.07 in normal to 0.60 +/- 0.08 nmol/mg protein in sensitized trachea; P < 0.05; n = 7) whereas the affinity of both high- and low-affinity binding sites for VIP increased as compared to that of normal trachea. Differences were not found in the binding capacities of normal and sensitized trachea. VIP content and binding did not differ in normal and sensitized lung. In conclusion, immunological sensitization produced changes in VIP tracheal content and binding but neither VIP-induced relaxation of isolated airways nor the influence of epithelium in this response was altered.

Environmental deprivation delays the maturation of motor pyramids during the early postnatal period

The effects of environmental deterioration upon the development of motor cortex was studied in 30 Sprague-Dawley albino rats during lactation (1st-18th postnatal days). The use of Golgi-Cox-Sholl methodology allowed qualitative and particularly quantitative evaluations since impregnation of neurons take place at random without any selectivity. Morphometric studies were assessed by measuring layers II-III pyramidal neurons, basal dendritic branching, under camera lucida. Early environmental impoverishment results in a highly significant decrease in the number and length of peripherical branches and terminal dendrites. These results extend previous observations made predominantly in non-motor cortices which indicate that during early postnatal life restrictions or enrichments of the environment may be associated with quantitative changes in the differentiation of cerebrocortical neurons. It is of upmost importance to consider that the potential effects of different types of epigenetic cues are highly selective since pyramids of pups subjected to mild nutritional manipulation during the same developmental period remained unaffected.

Relaxation by calcium antagonists of potassium-contracted trachea from normal and sensitized guinea-pigs: influence of epithelium and the surface of drug entry

A technique by which drug access was restricted to either the mucosal or the adventitial surface of tracheal rings, isolated from normal (unsensitized) or sensitized guinea-pigs, was used to study the role of the epithelium in the relaxation produced by calcium antagonists (verapamil, nifedipine, cinnarizine and flunarizine) of K(+)-induced contraction. In trachea from normal guinea-pigs, the relaxation to verapamil for unrestricted or mucosal drug entry was reduced in the absence of epithelium, whereas the relaxation produced by nifedipine, cinnarizine or flunarizine was unchanged. In sensitized trachea, the relaxation elicited by the calcium antagonists tested was similar in intact and epithelium-denuded tracheal rings irrespective of the surface of drug entry. These results confirm that the epithelium influences the relaxation to verapamil. This modulatory effect is absent in sensitized trachea and is not shared by other calcium antagonists.

Role of endothelium in the responses to noradrenaline in normal and sensitized guinea-pig aorta

1. The pharmacological reactivity of sensitized blood vessels has been less studied than that of the airways. Aorta rings were obtained from normal (non-sensitized) and actively sensitized guinea-pigs, and prepared for isometric recording of tension changes. 2. Noradrenaline (10 nM-0.1 mM), histamine (0.1 microM-0.1 mM) and KCl (10-100 mM) produced concentration-related contractions of normal tissues. Removal of endothelium resulted in a marked leftward and upward shift of the concentration-response curve for noradrenaline but it did not alter histamine- or KCl-induced responses. Pretreatment with L-NG-nitroarginine (L-NOARG, 30 microM), haemoglobin (5 microM) or ibuprofen (10 microM) enhanced noradrenaline-induced responses without affecting those to histamine or KCl. 3. Removal of endothelium or pretreatment with L-NOARG or ibuprofen did not alter agonist-induced responses in sensitized tissues. Acetylcholine (1 microM)-induced relaxation of the contraction produced by noradrenaline (1 microM) in intact rings was diminished in sensitized compared to normal tissues. 4. Neuronal uptake and release of [3H]-noradrenaline did not differ in normal and sensitized tissues. 5. Loss of the modulatory role of endothelium and other mechanisms may be involved in the hyperreactivity of sensitized guinea-pig aorta.

Early life environmental deterioration, nutrition and ontogenesis of the motor cortex in the rat: a Golgi study

Sprague-Dawley albino rats were subjected to an experimental paradigm in which environmental and nutritional variables were studied from birth to day 18. The use of Golgi-Cox-Sholl methodology allowed quantitative evaluations of neurons which were randomly impregnated with metallic mercury after fixation in a mercury salt. The nutritional treatment employed did not significantly influence the cytoplasmatic differentiation of cortical neurons although it was able to induce gross morphological modifications in body weight and size. By contrast, an impoverished surrounding during a limited period of time had a profound effect on the basal dendritic tree. The evidence presented here suggests the importance of the preweaning environment on the development of neural appendages. Motor pyramids of pups housed in deteriorated conditions underwent a progressive decrement in the length and number of peripheral branches and terminal dendrites. A decreased rate of cortical differentiation was also observed in overnourished pups as a result of reducing the litter size. This regressive event, can probably be attributed to social and sensory-motor limitations of the experimental group. However, to confirm this possibility, further research is required.

cDNA cloning and sequence analysis of human pancreatic procarboxypeptidase A1

Using polyclonal antibodies raised against human pancreatic procarboxypeptidases, a full-length cDNA coding for an A-type proenzyme was isolated from a lambda gt11 human pancreatic library. This cDNA contains standard 3' and 5' flanking regions, a poly(A)+ tail and a central region of 1260 nucleotides coding for a protein of 419 amino acids. On the basis of sequence comparisons, the human protein was classified as a procarboxypeptidase A1 which is very similar to the previously described A1 forms from rat and bovine pancreatic glands. The presence of the amino acid sequences assumed to be of importance for the zymogen inhibition by its activation segment, primarily on the basis of the recently reported crystal structure of the B form, further supports the proposed classification.

Frequency domain models of the EEG

The structure of the normal resting EEG crosspectrum SVV(omega) is analyzed using complex multivariate statistics. Exploratory data analysis with Principal Component Analysis (PCA) is followed by hypothesis testing and computer simulations related to possible neural generators. The SVV(omega) of 211 normal individuals (ages 5 to 97) may be decomposed into two types of processes: the xi process with spatial isotropicity reflecting diffuse, correlated cortical generators with radial symmetry, and processes that seem to be generated by more spatially concentrated, correlated sources. The latter are reflected as spectral peaks such as the process. The eigenvectors of the xi process are the Spherical Harmonic Functions which explains the recurring pattern of maps characteristic of the spatial PCA of qEEG data. A new method for estimating sources in the frequency domain which fits dipoles to the whole crosspectrum is applied to explain the characteristics of the localized sources.

Response to noradrenaline and histamine in normal and sensitized guinea pig aorta and its relation to endothelium

Pharmacological reactivity of sensitized blood vessels has been less studied than that of airways. Aorta rings were obtained from normal and actively sensitized guinea pigs and prepared for isometric recording of tension changes. Noradrenaline (10 nM-10 microM), histamine (0.1 microM-0.1 mM) and KCl (10-100 mM) produced concentration-related contractions of normal tissues. Removal of endothelium resulted in a marked left upward shift of the concentration-response curve to noradrenaline but it did not alter histamine- or KCl-induced responses. Pretreatment with ibuprofen (10 microM) or L-NG-nitroarginine (L-NOARG, 3.3 microM) enhanced noradrenaline-induced responses without affecting those to histamine or KCl. Removal of endothelium or pretreatment with ibuprofen or L-NOARG did not alter agonist-induced responses in sensitized tissues. Neuronal uptake and release of [3H]-noradrenaline did not differ in normal and sensitized tissues. Loss of the modulatory role of endothelium and other mechanisms may be involved in the hyperreactivity of sensitized guinea pig aorta.

Conservation of the sequence of the Alzheimer's disease amyloid peptide in dog, polar bear and five other mammals by cross-species polymerase chain reaction analysis

Neuritic plaque and cerebrovascular amyloid deposits have been detected in the aged monkey, dog, and polar bear and have rarely been found in aged rodents (Biochem. Biophy. Res. Commun., 12 (1984) 885-890; Proc. Natl. Acad. Sci. U.S.A., 82 (1985) 4245-4249). To determine if the primary structure of the 42-43 residue amyloid peptide is conserved in species that accumulate plaques, the region of the amyloid precursor protein (APP) cDNA that encodes the peptide region was amplified by the polymerase chain reaction and sequenced. The deduced amino acid sequence was compared to those species where amyloid accumulation has not been detected. The DNA sequences of dog, polar bear, rabbit, cow, sheep, pig and guinea pig were compared and a phylogenetic tree was generated. We conclude that the amino acid sequence of dog and polar bear and other mammals which may form amyloid plaques is conserved and the species where amyloid has not been detected (mouse, rat) may be evolutionarily a distinct group. In addition, the predicted secondary structure of mouse and rat amyloid that differs from that of amyloid bearing species is its lack of propensity to form a beta sheeted structure. Thus, a cross-species examination of the amyloid peptide may suggest what is essential for amyloid deposition.

Epithelium modulates the reactivity of sensitized guinea-pig trachea: influence of the surface of drug entry

A technique by which drug access was restricted to either the mucosal or the adventitial surface of tracheal rings isolated from sensitized guinea-pigs was applied to study the role of the epithelium in modulating responses to KCl, acetylcholine, histamine and antigen (bovine serum albumin, BSA). Epithelium removal did not alter the responsiveness or sensitivity of tracheal rings to KCl. In contrast, a leftward shift occurred for concentration-response curves to acetylcholine (concentration ratio (CR) = 4.1), histamine (CR = 2.9) and BSA (CR = 33.9) entering from the mucosal surface of de-epithelialized trachea. This shift was not associated with changes in the maximal effect of the spasmogens. Response to the adventitial entry of these spasmogens was not altered by epithelial stripping. These results confirm that the epithelium modulates tracheal responses to certain spasmogens including antigen challenge. This role was exclusively exerted for mucosal drug entry. The mechanism underlying this protective effect of epithelium remains to be determined.

Autolysis of proproteinase E in bovine procarboxypeptidase A ternary complex gives rise to subunit III

Extracts of bovine pancreatic tissue are shown by HPLC to contain two distinct ternary complexes of procarboxypeptidase A (subunit I), chymotrypsinogen C (subunit II) and either proproteinase E or subunit III. It is shown that proproteinase E in the complex generates subunit III by removal of 13 N-terminal residues when the former is allowed to autolyze in solution or when catalytic amounts of isolated active proteinase E are added to it. Autolysis of proproteinase E was accompanied by the loss of potential activity towards specific synthetic substrates and occurred at a higher rate in pancreatic juice than in pancreatic tissue extracts, even when both were processed in the presence of serine protease inhibitors. We conclude that subunit III (also called truncated protease E) is an autolytic product of proproteinase E and not an ab initio component of the native ternary complex.

Role of epithelium in agonist-induced contractile responses of guinea-pig trachealis: influence of the surface through which drug enters the tissue

1. A method has been used in guinea-pig isolated tracheal rings to achieve selective drug entry from the adventitial or mucosal surface. A study has been made of the effects of epithelium removal on responses to spasmogens entering the tissue solely from the adventitial or the mucosal surface. 2. Cumulative concentration-response curves for KCl (1 to 100 mM), acetylcholine (0.1 microM to 10 mM) and histamine (1 microM to 1 mM) were constructed in intact and epithelium-denuded tracheal rings in circumstances where drug entry was unrestricted or restricted to the adventitial or mucosal surface. 3. Epithelium removal did not alter the responsiveness or sensitivity of tracheal rings to KCl either when drug entry was unrestricted or when drug entry was restricted to the adventitial or mucosal surface. 4. When acetylcholine entered from the mucosal or adventitial surfaces of intact tracheal rings its concentration-response curve was displaced to the right with respect to that obtained for unrestricted drug entry. A greater rightward shift was observed for mucosal drug entry than for adventitial drug entry. Epithelium removal potentiated acetylcholine entering from the mucosal surface to a greater extent (27.5 fold) than it potentiated acetylcholine entering from both surfaces (4 fold). Epithelium removal did not potentiate effects of acetylcholine entering from the adventitial surface alone. 5. In intact tracheal segments, concentration-response curves for histamine entering from the mucosal surface were displaced to the right compared with those for histamine entering in an unrestricted fashion or from the adventitial surface alone. This displacement was absent in epithelium-denuded preparations. Epithelium removal potentiated (2-3 fold) histamine entering from the mucosal surface or entering in an unrestricted way. It did not potentiate histamine entering from the adventitial surface alone. 6. Our findings suggest that the epithelium does not modulate tracheal responses to KC1. Its ability to modulate responses to acetylcholine and histamine is observed when these spasmogens enter the tissue from the mucosal surface but not when they enter from the adventitial surface. The mechanism by which epithelium removal preferentially potentiates acetylcholine and histamine entering from the mucosal rather than the adventitial surface remains to be determined.

[Diffuse melanosis in metastatic malignant melanoma with melanuria]

We report an additional case of diffuse melanosis secondary to metastases from malignant melanoma in a patient, who was seen in our department shortly before death. We couldn't localize the origin of the primary neoplasm. After reporting the case, we discuss the pathogenesis of melanosis and possible sites of the primary tumor.