Knowledge and behaviour of nursing students on the prevention of healthcare associated infections

INTRODUCTION

Hospital infections, or "healthcare associated infections" (HAI) represent the most common and serious complications of healthcare. Adoption of safe care practices able to prevent or control the transmission of infections, both in hospitals and in other healthcare settings is crucial. The aim of the study is to assess the awareness about the risk factors and the most effective measures of prevention of HAI in the University of Ferrara nursing school students, giving particular attention to the hand hygiene practices and the use of standard precautions.

METHODS

339 students attending all the three years of course of the same academic year were enrolled. An anonymous questionnaire was administered in order to investigate the knowledge about three specific areas: infections associated with healthcare practices (HAI), standard precautions (SP) and hand hygiene (HH).

RESULTS

A sufficient level of knowledge by all the three groups of students was observed only in the SP area. A barely sufficient score was reached only by the third year students with regard to the proper HH. The level of knowledge about HAI was inadequate.

CONCLUSIONS

A periodically check of nursing students' knowledge would be advisable in order to fill any gaps, improve training, reduce HAI and increase prevention measures compliance.

[Epidemiological, social and public health aspects of tuberculosis in Ferrara in the 19th century]

Our first study of tuberculosis in Ferrara during the nineteenth century, whose results have been recently published, focused on disease treatment. Here we present the descriptive analysis of mortality, with the following results being attained: two behavioural patterns are detected with regard to the onset of disease, before and after 1850; TB is a specific disease that affects all parts of the body in all age groups: childhood, and active and passive populations; there are no significant differences with regard to gender; as regards the occupations performed by the deceased, those related to industry and agriculture and to various other activities and services are those with the highest mortality; tuberculosis has a seasonal pattern; summer and autumn are the periods of greatest prevalence (hot weather and humidity are factors that affect the respiratory system); among the forms of tuberculosis it can be observed that up to the year 1850 people died in Ferrara either of pulmonary tuberculosis or TB localised in other areas; from 1851 onward there appears to have been a dramatic change, with a decrease in unspecific diagnosis but the appearance of disease manifestations in its various clinical forms.

Nephrectomy modifies renal angiotensin II effects in kidney donors

BACKGROUND

Age, gender, menopausal status, a family history of hypertension, and renal vascular response to angiotensin II are involved in the progression of renal failure from its very beginning.

METHODS

In order to investigate their importance on this progression, we measured effective renal plasma flow (ERPF) and glomerular filtration rate (GFR), and calculated glomerular pressure (Pglo) and afferent and efferent arteriole resistances (by means of Gomez formulae) in 26 normotensive kidney donors before and after nephrectomy.

RESULTS

Renal reactivity to angiotensin was the only variable that affected changes in renal and glomerular hemodynamics after the loss of renal tissue: in subjects with greater angiotensin reactivity, higher afferent resistances (Ra) and lower glomerular filtration and pressure before nephrectomy change to higher efferent resistances (Re) and higher Pglo and filtration after nephrectomy.

CONCLUSIONS

In normotensive donors with a normal compensatory response to nephrectomy, baseline renal reactivity to angiotensin II can influence renal and glomerular hemodynamics 1 year after nephrectomy.

Molecular analysis of the fragile histidine triad (FHIT) tumor suppressor gene in vesical tumors of cattle with chronic enzootic hematuria (CEH)

The FHIT (fragile histidine triad) gene is a tumor suppressor gene known to be inactivated in many tumors including bladder tumors and is spanning FRA3B, a very active common fragile site in the human genome. We have recently isolated the bovine gene, and the aim of this study was to test whether FHIT presents altered expression patterns in vesical tumors of cattle with CEH (chronic enzootic hematuria). CEH is a common syndrome affecting Mediterranean cattle: clastogenic, mutagenic and cancerogenic substances released by the bracken fern (Pteridium spp) grazed by animals induce the formation of neoplastic lesions, among which bladder tumors have a high incidence. We analysed FHIT in 23 bladder tumors of CEH cattle looking at: 1) the methylation status of the CpG island comprising the promoter and part of exon 1; 2) the presence of altered FHIT transcripts; 3) the mRNA expression levels measured with a quantitative real time PCR (QRT-PCR) approach. Our results suggest that unlike in human tumors, FHIT in vesical tumors of CEH cattle is largely unmethylated. Furthermore, the same mRNA isoforms of FHIT were detected in tumors and in healthy tissues, including a novel isoform that was found in this study. Finally, QRT-PCR data did not reveal significantly altered expression profiles of FHIT transcripts. Further studies and larger sets of cases will be useful to confirm this finding, but the data seem to suggest that epigenetic modifications of FHIT and altered expression profiles are not a hallmark of bovine vesical tumors like they are in human tumors.

Effect of familial hypertension on glomerular hemodynamics and tubulo-glomerular feedback after uninephrectomy

Familial hypertension, glomerular hemodynamic alterations, and dysregulation of tubulo-glomerular feedback (TGFB) have all been associated with the development of chronic renal failure. In the present study we evaluated renal and glomerular hemodynamics and TGFB responses in healthy kidney donors either with or without familial hypertension, before and after nephrectomy. Para-amino-hippurate plasma clearance (CPAH) and inulin plasma clearance (CInu) were measured in 15 kidney donors before and 1 year after nephrectomy. All subjects were normotensive and were kept in a sodium-replete state. Both clearances were measured after 40 min of constant infusion of PAH and Inu, as well as 20, 30, 50, and 60 min after the intravenous administration of acetazolamide (5 mg/kg). Glomerular hemodynamics were calculated by means of the Gomez formulae. Nephrectomy caused the expected decreases in CPAH and CInu and increase in the filtration fraction (all P < .0001). The decrease in renal resistances of the remaining kidney was greater at the afferent (-24%, P = .0075) than at the efferent arteriolar level (-17%, P < .0001). The TGFB activation was not altered by nephrectomy or by familial hypertension. Effective renal plasma flow (ERPF) decrease after TGFB activation appeared earlier than glomerular filtration rate (GFR) decrease before (P = .01), but not after, nephrectomy (P = .48). The presence of familial hypertension was associated with increased glomerular pressure (P = .0004). This study suggests that uninephrectomy in healthy human subjects causes a greater decrease in afferent arteriolar resistances, but that TGFB responses are not quantitatively altered. Familial hypertension is associated with a tendency toward higher glomerular pressures.

Donor and recipient family histories of hypertension influence renal impairment and blood pressure during acute rejections

A previous historical prospective observational study, double blinded for knowledge of kidney donors' family history of hypertension, included 85 transplanted patients with stable renal function, not treated with cyclosporine, who were followed-up for an average of 8 yr and carefully characterized for the presence or absence of hypertension in the donor and recipient families. The recipients without a family history of hypertension, but grafted with a kidney coming from a "hypertensive" family, developed hypertension much more frequently than recipients grafted with a kidney coming from a "normotensive" family, or recipients with familial hypertension in whom the origin of the kidney did not influence the prevalence of hypertension after transplantation. In this second study of the same patients, it was found that these recipients with a "normotensive" family and a "hypertensive" kidney showed a greater increase of diastolic BP (P = 0.005) and a greater degree of acute renal damage (P = 0.004) during acute rejections than all of the other recipients. This extension study shows that a grafted kidney can transmit not only chronic hypertension, but also susceptibility to a greater rise in BP and more severe kidney impairment after an acute insult.

ACE Inhibitors and Renal Vascular Responses in the Spontaneously Hypertensive Rat

BACKGROUND: Substantial evidence has accumulated for the intrarenal generation of functionally important quantities of angiotensin II (Ang II). To assess the possibility that Ang II generation occurs beyond a barrier to diffusion from the vascular compartment, six angiotensin-converting enzyme (ACE) inhibitors varying widely in their lipid solubility were employed in the spontaneously hypertensive rat (SHR) and their normotensive controls (WKY). The biological end points were renal blood flow and its response to Ang II. RESULTS: Two ACE inhibitors, ramipril and captopril, induced a larger increase in renal blood flow and enhanced the renal vascular response to Ang II substantially more than did enalapril and lisinopril. The two prodrugs, enalapril and ramipril, which are substantially more lipophilic than the respective active drugs, enalaprilat and ramiprilat, showed equivalent responses. The partial agonist saralasin virtually abolished the renal vasodilator response to ramipril. The pattern of response was similar in WKY, but the responses were substantially smaller. CONCLUSIONS: The results support the concept that a functionally important compartment for intrarenal Ang II formation exists in the healthy rat and that this process is amplified in the SHR.

Which urinary proteins are decreased after angiotensin converting--enzyme inhibition?

It is believed that angiotensin converting-enzyme (ACE) inhibitors lower proteinuria by acting on glomerular hemodynamics. This hypothesis predicts that the urinary excretion of a tubular protein should be unaffected by ACE inhibition. In the present study we have compared the excretion of albumin and Tamm-Horsfall Glycoprotein (THGP), a protein secreted only by renal tubules, before and after ACE inhibition. Urinary protein excretion was measured with the Phast System, a method based on SDS polyacrylamide gel electrophoresis followed by silver staining, in 15 essential hypertensives, after at least 4 weeks of wash-out from any drug and after 2 months of ACE inhibition with oral Quinapril. After 2 months of ACE inhibition, blood pressure (BP), body weight, urinary output, heart rate, plasma glucose, plasma and urinary creatinine, urate and electrolytes, and creatinine clearance, were not different from baseline values. Plasma ACE activity decreased from 76 +/- 7 to 10 +/- 4 U/mL (mean +/- SEM, 2 tails paired t test, p = 0.0001). Both albumin and THP urinary excretions decreased from 51 +/- 6 to 43 +/- 4 mg/ 24 h (p = 0.05) and from 19 +/- 3 to 12 +/- 1 mg/24 h (p = 0.02), respectively. This unexpected result suggests that ACE inhibitors may act also at the level of renal tubular cells.

Accuracy of the urinary albumin titrator stick 'Micral-Test' in kidney-disease patients

BACKGROUND

A quick, accurate, and easy measurement of microalbuminuria can be useful for the management of many patients. The Micral-Test stick (Boehringer Mannheim, Germany) gives a semiquantitative estimation of urinary albumin concentration at discrete readings of 0, 10, 20, 50 or 100 mg/l. The purpose of this study was to test its accuracy.

METHODS

From 46 non-diabetic patients, 491 urinary samples were analysed both with Micral-Test and with immunochemical nephelometry.

RESULTS

Of 491 samples, 308 were from non-proteinuric patients (urinary albumin < 300 mg/day). In these patients the correlation coefficient of nephelometric values versus the stick readings was 0.79: 120/123 samples from non-microalbuminuric (< or = 30 mg/24 h) and 164/185 from microalbuminuric patients were correctly identified by the stick, giving an 89% sensitivity and a 98% specificity. The readings around the threshold for microalbuminuria (20 and 50 mg/l patches) were the most reliable ones. Analysis of the correct/uncorrect readings' ratio for every patch in the 245 samples in the 0-150 mg/l range shows a relative uniformity (chi2 = 8.5, P = 0.07), while analysis of the over/correct/underreadings for the 10, 20 and 50 patches, shows that incorrect responses tend to be underestimations for the 10 patch and overestimations for the 20 and 50 mg/l patches (chi2 = 10.5, P = 0.03).

CONCLUSIONS

The Micral-Test stick is useful for screening, but less reliable for follow-up, unless considerable changes in albumin excretion are expected.

Hypertension may be transplanted with the kidney in humans: a long-term historical prospective follow-up of recipients grafted with kidneys coming from donors with or without hypertension in their families

In several genetic hypertensive rat strains, transplantation studies have established that the kidney carries at least a portion of the genetic message for hypertension. In man it has, of course, been more difficult to obtain clearcut results. This historical prospective observational study, double-blinded for knowledge of donors' and recipients' family history for hypertension, concerns 85 transplanted patients, not treated with cyclosporine and with stable renal function, followed up for an average of 8 yr. Both the donors' and the recipients' families were carefully characterized for presence or absence of hypertension. After transplantation, in recipients without hypertension in their own families, a kidney coming from a "hypertensive" family determines less withdrawal and more introduction of antihypertensive therapy (AHT) than a kidney from a "normotensive" family (odds ratio for AHT introduction 5.0, confidence interval, 1.4 to 17.8; P = 0.017). In recipients with familial hypertension, the origin of the kidney does not influence the prevalence of hypertension after transplantation. More detailed analyses show that, in recipients without familial hypertension, the transplantation of a "hypertensive" kidney determines a tenfold larger increase in the requirement of antihypertensive therapy than the transplantation of a "normotensive" kidney, to obtain a similar blood pressure control (P = 0.003). This results is confirmed by the analysis of time-profile trends for antihypertensive therapy, adjusted for missing data, in the most clinically stable period (2nd to 10th yr after transplantation). The transmission of familial hypertension with the kidney is thus seen only in recipients coming from "normotensive" families, because a familial tendency for hypertension blunts the effect of receiving a "hypertensive" kidney.

Evaluation of the tubuloglomerular feedback system in human subjects

It has been shown in animals that GFR decreases after administration of a carbonic anhydrase inhibitor (CAI) because of activation of the tubuloglomerular feedback. However, the magnitude of this response has never been studied in healthy subjects, nor has the possibility of inhibiting tubuloglomerular feedback with frusemide (FRU). Changes in CCr, V, CNa, CCl, CH2O, CLi were studied before and after acute administration of acetazolamide (ACZ) to 11 normal subjects or FRU to 9 normal subjects. Both ACZ and FRU increased V, CNa, CCl and CLi. Only FRU decreased CH2O. ACZ but not FRU decreased CCr, despite lesser increases of V, CLi and CH2O+CCl (rough indexes of distal delivery). The magnitude of the GFR decrease after comparable increases in distal delivery varied greatly between subjects. There was a tendency for the subjects with lower basal GFRs to show tubuloglomerular feedback responses of lesser magnitude than those with higher GFRs. These results show that it is possible to study tubuloglomerular feedback and its sensitivity in humans using CAIs. FRU blocks the tubuloglomerular feedback response. Its sensitivity appears to vary widely in normal subjects.

Anatomy and examination of the elbow

The treatment of elbow injuries necessitates establishment of a proper diagnosis. An understanding of anatomic relationships serves as the basis for clinical evaluation. The history must ascertain the details of specific injury as well as identify intrinsic and extrinsic risk factors. Physical examination includes inspection, range of motion testing, palpation, provocative testing, and neuromuscular testing. Radiologic and ancillary testing supplement the clinical evaluation.

Urinary salt titrator stick: a useful and quick estimate of dietary sodium intake?

Repeated measures of urinary salt excretion are the best compromise between reliability and convenience for estimating dietary salt intake. In order to assess the accuracy of the Uropaper urinary salt titrator stick (giving discrete readings of 4, 6, 8, 10, 12 or 14 g/l of NaCl), 312 urine samples were analysed both with the stick and with an ion-selective electrode. There was a good stick-electrode correlation in all the 312 samples (r = 0.84). With a tolerance of +/- 1 g/l, the percentages of correct estimations dropped from 82% to 33% with increasing concentrations of NaCl in the urinary sample. For NaCl concentrations greater than 8 g/l (137 mmol/l) the error in the stick measurement consisted almost exclusively of overestimation of the electrode readings. These results were unaffected by the concentration of urinary potassium. No discrepancies were found among three different readers. This stick is easy to use and measures, with reasonable accuracy, low urinary NaCl concentrations. It could be useful for self-monitoring during low NaCl diets.

Epidemiology of infant deaths due to congenital malformations: Italy 1958-1981

The spatial and temporal distribution of infant death rates attributed to the single cause of congenital malformation (DCM) in Italy was studied for the period 1958-1981. Variation of DCM rates in this period was investigated for the whole country, for the three main geographical areas of the North, Center, and South, and for each of the 18 Italian regions (there are 20 administrative regions, but in this study Abruzzo were pooled with Molise and the Aosta Valley with neighbouring Piedmont). It was found that DCM decreases significantly with time. The decrease is considerable in the North and the Center of the country, whereas in the South temporal variation is minimal. There is a marked decrease of the variance of the DCM rates between regions with later years, possibly indicating a tendency to equalization of environmental effects in a large part of the peninsula.

Linkage of biopsy, cancer, and population records aimed at the estimation of family risks in neoplasia: a pilot study

STUDY OBJECTIVE

The aim was to link individual demographic and medical records into sibships to obtain the sibling distribution of biopsies and cancers, and thereby calculate heritability and recurrence risks in families, thus aiding early diagnosis and prevention of cancers.

DESIGN

The 157,823 individual records of the inhabitants of the town of Ferrara in Italy were automatically linked into 106,821 sibships. A 10% sample (10,842 sibships) was then extracted from the distribution of sibships and tabulated, for linkage to medical records.

PATIENTS

The biopsy records at the Institute of Pathological Anatomy of the University of Ferrara were manually linked to cancer records and then to sibships. It was possible to construct the distribution of 2062 biopsies and of 829 cancers in sibships.

RESULTS

From the distribution of biopsies and tumours in sibships, it was possible to estimate the incidence of tumours in the population (0.052) and in siblings of affected (0.083), and to apply to such distributions current methods for the estimate of heritability (h2 = 0.246) and of recurrence risks of tumours in sibships, age independent.

CONCLUSIONS

The study shows that the procedure resulting in the estimation of incidences and recurrence risks for tumours could be completely automated, and extended to whole populations and homogeneous subgroups in post industrial cultures.

[Gram-negative flora of horticultural produce destined for consumption mainly in the raw state]

A survey has been carried out to evaluate the recovery of Enterobacteriaceae in freshly consumed horticultural products. 64 samples of these vegetables random chosen in different stores in the General Vegetable Market of Ferrara have been examined among the families of Compositae (lettuce, prickly lettuce, cabbage lettuce, common chicory, artichoke), Umbrelliferae (curly parsley, carrot, celery, fennel), Cruciferae (garden cabbage, red radish), Liliaceae (onion), and Solanaceae (tomato). 654 bacterial lines were isolated, of which 92.5% were Enterobacteriaceae, found in all kinds of horticultural products, the more contaminated being celery, followed by fennel, onion, common chicory, curley parsley, tomato; less contaminated were the other vegetables. Serratia was found in 29.6% of the samples, Escherichia in 28%, Enterobacter in 21.6%, Hafnia in 8.3%, citrobacter in 4.9%, Klebsiella in 2.3% and Yersinia enterocolitica in 1.5%. The importance of horticultural products as source of contamination and colonization by Enterobacteriaceae, especially in hospital, is emphasized. On the basis of reported data, the Authors suggest an accurate observance on hygienic regulations in order to contain the microbic charge under borderline values, even if it is not demonstrated that environmental Enterobacteriacee have the same pathogenicity than clinical ones.

Family resemblance in blood pressure measurements

The correlation for diastolic and systolic blood pressure was studied in two samples of quartets each consisting of two pairs. The first sample comprised pairs of sisters and their husbands, and the second sample was comprised of brothers and their wives. All siblings were between 30 and 55 years of age and had been married for at least 5 years. It was found that unrelated men married to sisters had a significant correlation in both diastolic (r = 0.28) and systolic (r = 0.41) pressure. For systolic blood pressure, the correlation between pairs of unrelated men married to sisters was significantly larger than the homologous correlation existing in pairs of brothers married to unrelated women. The correlations of systolic and diastolic pressure in sisters were significantly smaller than the same correlations measured in the wives of brothers. The correlations in height for men, used as an internal control to compare marital and genetic effects, were unaffected by marriage, as expected. The correlations in height for pairs of sisters, however, were no larger than those observed in pairs of unrelated women married to brothers. It was concluded that in adult married men and women of the Ferrara population, aged 30 to 55 years, the influence of genetic factors on blood pressure is less important than the influence of cultural factors.

Mortality for Tracheal, Bronchial and Lung Cancer: Possibilities and Limits in Data Quality-Control

Linkage of various archives (municipal, hospital, autopsy) has enabled the authors to reconstruct the flow of information regarding death due to tracheal, bronchial or lung cancer (TBL ca) for the population residing within the Municipality of Ferrara during the period 1983–1985. The authors subsequently attempted to verify the cause of death by performing quality controls on clinical charts, radiologic findings, cytohistologic examinations and autopsy findings. Analysis of the data obtained in this manner suggests that municipal records are more « accurate » than are hospital records. The authors likewise indicate the usefulness and importance of the autopsy for a correct diagnosis of cause of death.

Hypertension and the kidney: lessons learned from transplantation

This review discusses the analogies between some experimental models of arterial hypertension and some probable causes of hypertension in kidney-transplanted patients. Some subgroups of these patients have striking similarities with some animal models: Data suggest that the genetic predisposition to hypertension can be transmitted with the kidney, similar to the transplantation experiments in genetically hypertensive rat stains. Patients with graft artery stenosis, if previously binephrectomized, present the same puzzling sequence of events in the development of hypertension as the one-kidney one-clip Golblatt hypertension animal models. "Native kidney" hypertension can be related to a state of chronic angiotensin excess as in the chronically angiotensin-infused animals. Confounding variables include chronic steroid therapy, chronic rejection, and the possible role of renal nerve regeneration. There are also animal models available for these contributing factors that allow us to understand the many facets of post transplant hypertension better.

Differential pressor and renal vascular reactivity to angiotensin II in spontaneously hypertensive and Wistar-Kyoto rats

The suggestion has been made that the Okamoto strain of spontaneously hypertensive rats (SHR) shares some features with a subgroup of patients with essential hypertension, called nonmodulators. One feature of nonmodulators is a renal blood flow response to angiotensin II (ANG II) that is blunted on a high salt diet; the blunted renal vascular response is corrected by converting enzyme inhibition. Renal blood flow (electromagnetic flowmeter) and pressor responses to graded ANG II doses (5-300 ng) were assessed in 24 SHR and 24 Wistar-Kyoto rats (WKY) ingesting 1.6% Na. In comparison to WKY, blood pressure was higher in SHR (155 +/- 4 vs 106 +/- 2 mm Hg; p less than 0.001), renal blood flow was lower (6.9 +/- 0.5 vs 8.2 +/- 0.4 ml/min/g; p less than 0.05), and the pressor response to ANG II was enhanced, (p less than 0.0005) but the renal vascular response was blunted (p less than 0.005). Captopril (1-30 mg/kg) reduced blood pressure more in SHR than in WKY but increased renal blood flow similarly in both strains. The blunted renal vascular response to ANG II in SHR was reversed by captopril, but inhibition of converting enzyme in the kidney did not parallel systemic inhibition. Maximum blockade of converting enzyme in the kidney appears to require a larger captopril dose than is required for systemic inhibition. These results suggest that the renal blood supply in SHR also shares some of the characteristics of nonmodulators and that the action of captopril on the renal blood flow probably reflects reversal of inappropriate intrarenal ANG II formation.

Different reactivity to angiotensin II of peripheral and renal arteries in spontaneously hypertensive rats: effect of acute and chronic angiotensin converting enzyme inhibition

We assessed renal blood flow and pressor responses to graded angiotensin II doses in spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats ingesting a diet containing 1.6% sodium basally and after acute and chronic angiotensin converting enzyme (ACE) inhibition with captopril. In the basal state the pressor response to angiotensin II was enhanced (P<0.0005) and the renal vascular response was blunted (P<0.005) in SHR compared with WKY rats. After acute captopril administration the pressor response was enhanced in both strains, and the difference between them was maintained, while the renal vascular response was enhanced in both, but more in SHR, so that the renal vascular response in the SHR became larger than in WKY (P<0.0001). Chronic captopril treatment blunted both pressor and renal responses in WKY rats, but only the pressor response in SHR. The renal vessels of SHR seem to be different from those of WKY rats in reaction to exogenous angiotensin II, and in response to both acute administration of captopril (probably acting through blockade of angiotensin II production) and chronic administration of captopril (probably acting mainly through accumulation of kinin or production of prostaglandins).

A renal abnormality in the Milan hypertensive strain of rats and in humans predisposed to essential hypertension

Many similarities in kidney-function abnormalities were found between hypertensive rats of the Milan strain (MHS) and young normotensive human subjects with hypertensive parents, compared with the appropriate controls. These similarities included an increased glomerular filtration rate, increased pressor effect of the kidney after transplantation, increased 24-h urinary output and lower plasma renin activity and urinary kallikrein. The isolated MHS kidney perfused in vitro with an artificial medium had a higher glomerular filtration rate, a higher urinary output, higher tubular sodium reabsorption and higher oxygen consumption than the kidney of control Milan normotensive rats (MNS). Further, reogenic sodium transport across brush border vesicles isolated from proximal tubular cells is faster in MHS than in MNS. Erythrocytes and proximal tubular cells of MHS have a lower volume and sodium content than those of MNS, while sodium transport is faster and the Ca2+-ATPase at Vmax is lower. This indicates that the 'genetic' cellular abnormality responsible for the renal-function abnormality and the hypertension is also present in erythrocytes. Thus these cells may be used to study the genetic cellular mechanisms of hypertension. Experiments with bone marrow transplantation and with F2 hybrids obtained by crossing the F1 (MHS X MNS) hybrids showed that the MHS erythrocyte abnormalities are genetically determined within the stem cells and are genetically associated with the hypertension. Since, in human hypertensives, there was a correlation between abnormal erythrocyte sodium transport and renal function, it is proposed that erythrocytes may be used in studying the cellular molecular mechanisms of hypertension.

Cell membrane abnormalities and genetic hypertension

Evidence indicates that an alteration in kidney function has a causal role in the pathogenesis of hypertension in the Milan hypertensive strain (MHS) rat. At the prehypertensive stage, these animals have increased glomerular filtration rate and 24-hour urinary output, whereas plasma renin activity and urinary kallikrein are lower. After transplantation, the MHS kidney increases the blood pressure of a normotensive recipient. Micropuncture experiments, where single nephron filtration rate, tubuloglomerular feedback, proximal tubular reabsorption, micro-pressures in tubuli, and interstitium and interstitial oncotic pressure were measured, suggest that the intrinsic ability of MHS proximal tubular epithelium to reabsorb solute and water is greater in prehypertensive MHS rats than in Milan normotensive strain (MNS) rats. Also rheogenic Na transport across the brush-border vesicles isolated from proximal tubular cells is faster. When erythrocytes and proximal tubular cells of MHS rats are compared to those of MNS rats, the former have smaller volume and Na content, whereas the Na transport is faster and the Ca ATPase at Vmax is lower. This indicates that the genetic cellular abnormality responsible for the renal functional abnormality and hypertension is also present in erythrocytes. Moreover, MHS erythrocyte abnormalities are genetically determined within the stem cells and are genetically associated with hypertension. Because a correlation was also found in human hypertension between erythrocyte Na transport abnormality and renal function, it is proposed that the erythrocyte may be used for studying the genetic molecular mechanisms of hypertension.

Genetic and experimental hypertension in the animal model-similarities and dissimilarities to the development of human hypertension

In this article, we present the results we have obtained from experimental and genetic models of human essential hypertension, in order to investigate those findings relevant to understanding the time course and the mechanisms underlying the human disease. With experiments on the renal artery constriction in the conscious dog, we have shown that a kidney lesion can produce a form of hypertension not different, in the established phase, from the essential one and that the onset of this form follows a phasic pattern during which the initial stages are crucial for understanding the mechanisms leading to hypertension. We also consider a rat model (MHS) that spontaneously develops a form of hypertension very similar to the human disease. In this model, we have demonstrated by a kidney cross-transplantation experiment and functional studies that the kidney is responsible for the rise in blood pressure and that the organ dysfunction is probably due to a primary abnormality in ion handling of the cell membrane. This cellular alteration, detected both in MHS erythrocytes and in their kidney proximal tubular cells, should be the cause for the higher rate of kidney Na+ reabsorption observed in the MHS. Comparing this animal model with, at least, a subgroup of humans prone to develop hypertension or already hypertensive, it is possible to detect a series of similarities in the kidney function, hormonal pattern, and cellular function of the two species that allows us to argue that the MHS is a suitable model from which to draw conclusions relevant to the pathogenesis of essential hypertension in some humans.

Hypertension in man with a kidney transplant: role of familial versus other factors

Genetic factors are clearly involved in the pathogenesis of essential hypertension in man. In at least three rat models of genetic hypertension it is possible to transplant the hypertension with the kidney. To see whether or not the same is true for humans, we carried out a 2-year retrospective study of 50 selected recipients of a cadaver kidney. We correlated the following factors by multivariate statistical analyses: presence or absence of hypertension in the family of donor and recipients; donor's and recipient's age; mean blood pressure (MBP) and antihypertensive therapy (AHT) score during dialysis; months of dialysis and body surface before transplantation; body weight, plasma creatinine, prednisone dosage and cumulative rejections with MBP and AHT score at various time intervals after transplantation. The results obtained showed that, considering the recipients coming from normotensive families, the AHT score after transplantation was significantly greater (p less than 0.05 1st and p less than 0.01 2nd year) in the patients receiving a kidney removed from donors with hypertensive families than in patients receiving a kidney removed from donors with normotensive families. This difference was not present when the recipients coming from hypertensive parents were considered. AHT score after transplantation is also correlated with AHT score on dialysis (p less than 0.01 1st and 2nd year), body weight (p less than 0.02 1st and p less than 0.01 2nd year), cumulative rejections (p less than 0.025 1st and 2nd year) and inverse MBP after dialysis (p less than 0.025 2nd year).

Genetic hypertension and the kidney

The relationship between the kidney and genetic hypertension has been assessed in light of the changes seen in some kidney and cell functions during the phases preceding and accompanying the development of "genetic" types of hypertension in rats and humans. Comparison of the kidney function of normotensive subjects likely to develop hypertension with that of matched controls resistant to hypertension showed, in the former, a higher glomerular filtration rate (GFR), greater tubular reabsorption, larger 24-h urinary output, larger fraction of cardiac output to the kidney, and lower plasma renin activity. After the transplantation of a kidney from a subject in the hypertension-prone group, recipients had higher blood pressure and required more antihypertensive therapy than recipients of kidneys from the hypertension-resistant group. In humans this finding is not as clear as in rats. During the development of hypertension most of these differences in kidney function in the two groups of subjects tend to disappear. The changes in cell function, measured particularly in rats, were consistent with the organ function changes. Cell volume and sodium content were lower, while the transport rate across the cell membrane was faster in proximal tubular cells of rats with genetic hypertension than in the appropriate controls. This is in keeping with the concept of a primary increase in proximal tubular reabsorption leading, on the one hand, to an increase in GFR and renal blood flow and a decrease in renin and, on the other, to an increase in blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood pressure in patients with four different primary glomerulopathies

It is well known that patients with different kidney diseases have different prevalence of hypertension, independent of renal function. To investigate whether a lesion of some portion of the glomerular tuft, without renal insufficiency, is associated more frequently with high blood pressure, we undertook a retrospective study on 189 patients analyzing by means of multiple regression analysis as independent variables : type of glomerulopathy (IgA Nephropathy, Acute Glomerulonephritis, Membranous Glomerulonephritis and Focal Glomerulosclerosis), sex, age, body weight, plasma creatinine, plasma and urinary proteins, plasma urate, time interval first symptom-renal biopsy and steroid therapy. The dependent variable was a Principal Component formed by Mean Blood Pressure and an Antihypertensive Therapy score, calculated with a computer program. Focal Glomerulosclerosis patients had a higher prevalence of hypertension and a higher Principal Component value than patients of the other 3 groups. Plasma urate was correlated and time interval first symptom-renal biopsy was inversely correlated to Principal Component. These observations suggest that sclerosis of the glomeruli is the lesion most often associated with hypertension. On the other hand, since plasma urate is correlated with blood pressure also in "essential" hypertensives, it seems likely that hyperuricemia is a phenomenon secondary to hypertension.

Influence of familial hypertension of the donor on the blood pressure and antihypertensive therapy of kidney graft recipients

The possibility that some hereditary factors favoring the development of 'essential' hypertension in man may act through modification of kidney function was evaluated in a retrospective study of 36 renal transplant recipients followed for 1 year. The patients were divided into two groups of 18 subjects each, matched for age, sex, body surface area, familial hypertension, duration of hemodialysis before transplantation and original kidney disease. In the first group, at least one of the donor's parents was hypertensive and in the second group all the members of the donor's family were normotensive. Plasma creatinine, daily dose of prednisone, number of rejection episodes and blood pressure were almost the same in both groups, but the requirement for antihypertensive therapy was significantly greater in the first group during the first 4 months after transplantation (p less than 0.05). Therefore, it seems reasonable to consider that there is some influence of familial existence of hypertension on the renal pressure regulatory mechanisms.