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Biomedical subjects

S H Jacobson

Publications and source records attributed to S H Jacobson.

At least 73 records · Page 4Linked to original sources
PubMed1992

Serum resistance in Escherichia coli strains causing acute pyelonephritis and bacteraemia.

The capacity of Escherichia coli to resist the bactericidal action of serum was examined in 367 clinical isolates obtained from children with acute pyelonephritis (n = 57), adults with acute pyelonephritis (n = 55), non-diabetic patients with bacteraemia (n = 101), diabetic patients with bacteraemia (n = 65) and from the faecal flora of healthy controls (n = 89). The incidence of serum-resistant E. coli strains was significantly higher in pyelonephritogenic strains from children and adults (93% and 82%) as compared to faecal control strains (57%, p less than 0.001 and p less than 0.005 respectively). Strains causing bacteraemia in non-diabetic and diabetic patients were more often serum resistant (72% and 80%) as compared to control strains (p less than 0.05 and p less than 0.001 respectively). The frequency of serum-sensitive strains was similar in diabetic patients with decreased renal function or proteinuria compared to those with normal renal function. There were no significant correlations between serum resistance of E. coli and expression of P fimbriae, type I fimbriae or mannose-resistant haemagglutination, cell surface hydrophobic properties, production of aerobactin, haemolysin or cytotoxic necrotizing factor in 53 pyelonephritogenic strains from adult patients.

Acute Disease↗
PubMed1992

Blood pressure reduction during hemodialysis correlates to intradialytic changes in plasma volume.

Blood pressure alterations during hemodialysis were related to changes in body fluid in 14 patients with chronic renal failure. Changes in plasma volume (PV) and extracellular volume (ECV) were calculated from determinations of fluid volumes before and after hemodialysis, using 125I-albumin and 51Cr EDTA respectively. Reduction in body water was estimated from body weight changes. Weight loss was 3.3 +/- 0.3 kg (range 1.8-6.0 kg). The relative reduction of fluid was greater in the ECV, 21.6 +/- 3.2%, compared to plasma volume, 6.9 +/- 1.8%. The reduction in systolic blood pressure was related to both absolute (r = 0.66, p less than 0.05) and relative PV reduction (r = 0.72, p less than 0.02). There was no correlation between blood pressure reduction and weight loss or ECV changes. Only minor alterations were found in diastolic blood pressure. Plasma volume maintenance relates to blood pressure changes. Plasma volume monitoring could be useful for improving intradialytic hemodynamic control.

Adult↗
PubMed1991

Effects of alpha 2-adrenergic blockade on renal hemodynamics in patients with insulin dependent diabetes mellitus.

The role of renal alpha 2-adrenoceptors in the regulation of glomerular filtration and renal perfusion is unknown. We studied the effects of alpha 2-adrenergic blockade on renal hemodynamics in six patients with insulin-dependent diabetes mellitus (IDDM) and in six healthy subjects. At the basal state, glomerular filtration rate (GFR) was higher in IDDM although the difference from control levels was not statistically significant. Volume expansion, achieved by infusion of isotonic sodium chloride solution, during placebo infusion induced a significant drop in GFR in healthy subjects but not in IDDM patients. Infusion of the alpha 2-adrenoceptor antagonist idazoxan did not further modify the effect of volume expansion on GFR. Renal plasma and blood flow as well as filtration fraction were not significantly changed by volume expansion or idazoxan infusion. Plasma renin activity and plasma aldosterone levels decreased during volume expansion in both IDDM and control subjects. In conclusion, volume expansion induced decreased GFR in healthy controls but not in IDDM patients. Since infusion of idazoxan did not affect GFR or other parameters of renal hemodynamics, renal alpha 2-adrenoceptors do not seem to be involved in the regulation of renal function. Hence, enhanced renal alpha 2-adrenoceptor activity is not likely to underlie hyperfiltration as seen in IDDM.

Adrenergic beta-Antagonists↗
PubMed1991

Relative importance of eight virulence characteristics of pyelonephritogenic Escherichia coli strains assessed by multivariate statistical analysis.

We have previously reported univariate statistical analysis of the prevalences of putative virulence determinants in Escherichia coli isolated from children and adults with acute pyelonephritis. The expression of P-fimbriae, cell surface hydrophobicity, mannose resistant haemagglutination, haemolysin synthesis, cytotoxic necrotizing factor production and aerobactin mediated iron uptake occurred more often in a collection of 115 Escherichia coli strains isolated from children and women with acute non-obstructive pyelonephritis compared to 96 strains isolated from the commensal fecal flora. With the aim to study which of these virulence markers were independently associated with strains causing infection we performed a multivariate statistical analysis with the data from these strains. The previously proposed virulence factors, expression of type 1 fimbriae and adhesion to HeLa cells were also included in the analysis. P-fimbriae, mannose resistant haemagglutination and the production of haemolysin were, in the multivariate analysis, associated with strains isolated from patients with acute pyelonephritis.

Acute Disease↗
PubMed1991

A five-year prospective follow-up of women with non-obstructive pyelonephritic renal scarring.

Fifty women with pyelonephritic renal scarring were prospectively followed for five years and the changes in renal function were related to blood pressure control, plasma renin activity, urinary albumin excretion and the incidence of urinary tract infections (UTI). Five patients (10%) developed end stage renal disease. All these patients had bilateral disease, proteinuria and anti-hypertensive treatment at presentation. The mean +/- SD glomerular filtration rate (GFR) of all patients with renal scarring was 74 +/- 27 ml/min x 1.73 m2 at presentation which was significantly lower than the GFR in 55 patients with a recent episode of acute pyelonephritis (p less than 0.001) and 10 healthy controls (p less than 0.001). GFR and age corrected GFR decreased significantly during follow-up (p less than 0.001) and p less than 0.02 respectively). The decrease in GFR was significantly higher in patients with bilateral scarring, in patients on blood pressure treatment and in patients with an episode of symptomatic UTI during follow-up. Eight patients (16%) had antihypertensive treatment at presentation and another 11 patients (26%), of whom 10 had bilateral scarring, developed hypertension (greater than 140/90 mmHg) during follow-up. Seventy-five per cent of all patients had symptomatic UTI and 40% had an episode of acute pyelonephritis during follow-up. In conclusion, patients with pyelonephritic scarring have a high incidence of UTI and are at high risk of developing renal failure and hypertension. It is essential that recurrent episodes of symptomatic UTI are treated promptly and that blood pressure is monitored carefully in these patients.

Adult↗
PubMed1990

Production of cytotoxic necrotizing factor, verocytotoxin and haemolysin by pyelonephritogenic Escherichia coli.

Two hundred and thirty-two strains of Escherichia coli isolated from children with non-obstructive acute pyelonephritis (n = 65), women with non-obstructive acute pyelonephritis (n = 63) and the faecal flora of healthy children (n = 33) and adults (n = 71) were examined for cytotoxic necrotizing factor production, haemolysin synthesis, verocytotoxin production and expression of mannose-resistant haemaglutination of human erythrocytes. Forty-eight per cent of the pyelonephritogenic Escherichia coli strains produced cytotoxic necrotizing factor and 61% produced haemolysin compared to 25% and 27% of faecal control strains (p less than 0.001 and p less than 0.001 respectively). Cytotoxic necrotizing factor production did not occur among the non-haemolytic Escherichia coli strains which confirms the close association between these two toxic factors. The bacterial phenotypes producing both haemolysin and cytotoxic necrotizing factor, and the phenotype expressing both these toxic factors and mannose-resistant haemagglutination occurred significantly more often in pyelonephritogenic strains than in faecal isolates (p less than 0.001). Haemolytic strains without the ability to produce cytotoxic necrotizing factor were more common in faecal isolates than in uropathogenic strains (p = 0.05). Strains lacking the ability to synthesize both these toxins were also over-represented in faecal isolates (p less than 0.01).

Adult↗
PubMed1990

Whole body impedance measurements reflect total body water changes. A study in hemodialysis patients.

Fluid volume changes during hemodialysis was monitored by continuous whole body impedance measurements. The fluid changes recorded using this method was compared to fluid volume changes measured in plasma water (PV) using 125I-albumin, and extracellular volume (ECV) using 51Cr-EDTA before and after treatment, and total body water (TBW) changes reflected by continuous bed scale monitoring. Changes in impedance correlated to TBW changes, r = 0.80, p less than 0.001, while correlations to changes in ECV and PV were: r = 0.57 and r = 0.55, respectively, p less than 0.05. Alterations in body fluid volumes recorded with whole body impedance is best correlated to total body water changes. The use of continuous whole body impedance monitoring has been shown to offer a simple non-invasive method for recording total body water changes during hemodialysis.

Aged↗
PubMed1990

Phenotypic differences and characteristics of pyelonephritogenic strains of Escherichia coli isolated from children and adults.

We examined the frequency of bacterial strains expressing cell surface hydrophobicity, P-fimbriae, mannose-resistant haemagglutination (MRHA), type I fimbriae, production of aerobactin, haemolysin synthesis (Hly), production of cytotoxic necrotising factor (CNF) and HeLa cell adherence in 126 strains of Escherichia coli isolated from children (n = 65) and women (n = 61) with acute non-obstructive pyelonephritis. Previous investigations have shown that pyelonephritogenic strains of E. coli more often express hydrophobic properties, P-fimbriae, MRHA, aerobactin-mediated iron uptake, Hly and CNF production than strains isolated from the faecal flora of healthy persons. The objective of the present study was to examine phenotypic differences between strains of E. coli obtained from children with their first episode of acute pyelonephritis and strains from women with non-obstructive acute pyelonephritis. Of the pyelonephritogenic strains of E. coli isolated from children, 98% expressed cell surface hydrophobic properties compared to 82% isolated from adults (P = 0.004). Strains from children and adults had the same ability to assimilate iron and equally often expressed P-fimbriae, MRHA and type I fimbriae. Strains from children with acute pyelonephritis more significantly expressed Hly (72%) and CNF (58%) than did pyelonephritogenic strains from adults (49 and 37% respectively, P = 0.013 and P = 0.028 respectively). The frequency of HeLa cell adherence was similar and low in both groups. The phenotype aerobactin+ Hly+ and Hly+CNF+ was found significantly more often in pyelonephritogenic strains from children than in strains from adults (P = 0.006 and P = 0.028 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Cell surface hydrophobicity, adherence to HeLa cell cultures and haemagglutination pattern of pyelonephritogenic Escherichia coli strains.

Cell surface hydrophobicity, haemagglutination pattern and adherence to HeLa cells were examined in 230 strains of Escherichia coli collected from women (n = 61 strains) and children (n = 65 strains) with non-obstructive acute pyelonephritis and in 104 faecal control strains of E. coli from healthy adults (n = 71 strains) and children (n = 33 strains). Pyelonephritogenic E. coli strains showed a significantly increased incidence of hydrophobic properties (90%) and mannose resistant haemagglutination (MRHA) of human erythrocytes (83%) than faecal control strains (64 and 23% respectively, P less than 0.001 in both cases). Mannose sensitive haemagglutination (MSHA) was observed in 48% of the pyelonephritogenic E. coli strains and in 50% of the faecal control strains (NS). The incidence of adherence to HeLa cells was low both in pyelonephritogenic and faecal control strains, 6 and 7% respectively (NS). The bacterial phenotypes MRHA + MSHA + and MRHA + MSHA- appeared significantly more often in pyelonephritogenic E. coli strains (35 and 48% respectively) than in faecal control strains (5 and 17% respectively, P less than 0.001 in both cases). The phenotype MRHA- MSHA + occurred significantly more often in control strains (45%) than in pyelonephritogenic strains (13%, P less than 0.001). Eighty-three per cent of the pyelonephritogenic E. coli strains expressing hydrophobic properties showed MRHA and 50% of the hydrophobic strains showed MSHA. There were no significant correlations between cell surface hydrophobic properties and haemagglutination pattern or adherence to HeLa cells in pyelonephritogenic E. coli strains nor in faecal control strains.

Acute Disease↗
PubMed1990

Overrepresentation of blood group non-secretors in adults with renal scarring.

Host factors are important in the pathogenesis of pyelonephritic renal scarring. The present study used blood group secretor state as a population marker to determine if patients developing renal scarring are a selected subgroup of individuals with urinary tract infections (UTI). Non-secretors represented 15/43 (35%) of the patients with renal scarring but only 7/41 (17%) of the patients without renal scarring (p = 0.059 and NS respectively vs. healthy controls 22%). The frequency of non-secretors among P1 phenotype patients with renal scarring was 38% (p = 0.05 vs. healthy controls). Among the patients born after the introduction of regular use of antibiotic treatment for UTI the frequency of non-secretors was 55% in the scarred group compared to 13% in the unscarred group (p = 0.011). Thus, in this younger group of patients with renal scarring 6/10 (60%) of the non-secretors developed renal scars compared to 5/32 (16%) of the secretors (p less than 0.05). Our data confirm that blood group non-secretors are overrepresented in patients with non obstructive renal scarring suggesting that blood group non-secretor state might be a host marker to consider for the subgroup of individuals with recurrent UTI at risk to develop renal scars. Renal function was not influenced by blood group secretor state. The mean glomerular filtration rate within the scarred group was similar for secretors and non-secretors (80 ml/min X 1.73 m2 and 79 ml/min X 1.73 m2, respectively). Whether blood group secretor state also is involved in the scarring process remains to be investigated.

ABO Blood-Group System↗
PubMed1990

Altered vasopressin release and osmotic regulation during exercise in patients with pyelonephritic renal scarring.

Children and adults with pyelonephritic renal scarring are at high risk of developing hypertension. The objectives of the present investigation were to study if it is possible to detect early disturbances in blood pressure (BP) control and secretion of hormones involved in the regulation of BP and renal function, in patients with renal scarring. We studied renal function at rest, BP regulating hormones and BP at rest and during graded bicycle exercise until exhaustion. The 22 patients with renal scarring had significantly lower glomerular filtration rate and renal blood flow than the 13 healthy age-matched controls. At rest, the patients had higher diastolic (p less than 0.01) and mean arterial BP (p less than 0.02), higher plasma renin (p = 0.06) and higher serum osmolality (p less than 0.001) but there were no significant differences in systolic BP, angiotensin II, aldosterone or vasopressin (AVP). The patients with renal scarring had higher AVP than the controls during light and moderate exercise and 15 min after maximal exercise. BP and renal hormones increased significantly but similarly during exercise in both patients and controls. There were no significant differences in BP control or release of pressure-regulating hormones at maximal exercise. Maximal exercise did not evoke pathological BP response in normotensive young adults with pyelonephritic renal scarring. The increase in serum osmolality and hypersecretion of AVP during light and moderate exercise may be important in the pathogenesis of hypertension in this group of patients.

Adult↗
PubMed1989

Development of hypertension and uraemia after pyelonephritis in childhood: 27 year follow up.

OBJECTIVE: Determination of the long term incidence of uraemia, hypertension, and toxaemia in pregnancy associated with non-obstructive focal renal scarring after pyelonephritis in childhood 25-35 years earlier. DESIGN: 27 Year follow up of patients with non-obstructive focal scarring identified from a retrospective review of intravenous urograms performed in childhood between 1951 and 1967. SETTING: Paediatric primary referral centre and urological clinic in tertiary referral centre. PATIENTS: 30 Patients (mean age 33 (range 22-41] with non-obstructive focal renal scarring first detected between 1951 and 1967 and a history of febrile urinary tract infection. MAIN OUTCOME MEASURE: Hypertension and complications of renal damage. RESULTS: Three patients had developed end stage renal disease, seven had developed hypertension, two of 16 women had a history of toxaemia during pregnancy, and seven patients had undergone renal surgery during follow up. Of the 20 patients who had neither had renal surgery nor had end stage renal disease, all had a significantly lower glomerular filtration rate and renal plasma flow and higher diastolic blood pressure, mean arterial blood pressure, plasma renin activity, and serum beta 2 microglobulin concentration than 13 healthy age matched controls. Diastolic blood pressure and plasma renin activity were positively correlated (r = 0.50, p less than 0.05) and so were fractional sodium excretion and both systolic and diastolic blood pressures (r = 0.54, p less than 0.01, r = 0.51, p less than 0.01 respectively). The progress of renal damage was unrelated to the incidence of recurrent infections. CONCLUSIONS: Children with focal renal scarring due to pyelonephritis are at high risk of serious long term consequences. It is essential that they are given adequate attention and care during adolescence and pregnancy.

Adult↗
PubMed1989

Hydrophobic properties of Escherichia coli causing acute pyelonephritis.

Cell surface hydrophobic properties and expression of P-fimbriae were examined in 130 strains of Escherichia coli derived from women (n = 66) and children (n = 64) with acute non-obstructive pyelonephritis and in 170 faecal strains of E. coli from healthy adults (n = 103) and children (n = 67) by use of the salt aggregation test and the P-fimbriae-specific particle agglutination test. The strains of E. coli isolated were aggregated in salt solutions of varying molarity (0.001-1.6 M final concentration). Patients with predisposing medical or urological conditions in the urinary tract were excluded. Pyelonephritic strains of E. coli from the women and children had a higher degree of cell surface hydrophobicity (80 and 98% respectively) than faecal strains from healthy adults and children (57 and 82% respectively, P less than 0.01 and P less than 0.01). Both pyelonephritic and faecal strains of E. coli from the children were more often salt aggregation positive (hydrophobic) than faecal strains of E. coli from healthy adults (P less than 0.01 and P less than 0.001, respectively). Pyelonephritic strains of E. coli from women and children were more often P-fimbriated (79 and 84% respectively) than faecal control strains from women and children (15 and 33%, P less than 0.001 and P less than 0.001, respectively) but there was no significant correlation between expression of P-fimbriae and cell surface hydrophobicity.

Adult↗
PubMed1988

Incidence of aerobactin-positive Escherichia coli strains in patients with symptomatic urinary tract infection.

A total of 323 Escherichia coli strains from children with primary acute non-obstructive pyelonephritis (n = 144) or cystitis (n = 56) and from adults with acute non-obstructive pyelonephritis (n = 66) or cystitis (n = 57) were examined for presence of the aerobactin-mediated iron uptake system and expression of P-fimbriae. Overall, pyelonephritogenic Escherichia coli strains were significantly more often aerobactin-positive (72%) than cystitis strains (42%) (p less than 0.001). Seventy-three percent of the isolates from children with acute pyelonephritis were aerobactin-positive compared to 54% of the cystitis strains (p less than 0.05). Pyelonephritogenic Escherichia coli strains from adults were also significantly more often aerobactin-positive (70%) than cystitis strains (30%) (p less than 0.001). The cystitis strains from children were more often aerobactin-positive than cystitis strains from adult patients (p less than 0.05). There was a significant correlation between presence of the aerobactin-mediated iron uptake system and expression of P-fimbriae in all strains (p less than 0.001).

Adolescent↗