Biomedical subjects

A Cucchi

Publications and source records attributed to A Cucchi.

31 records · Page 2Linked to original sources

PubMed1993

The spoOA and degU genes of Bacillus subtilis show genetic homology.

The transformation efficiency of competent Bacillus subtilis degU32(Hy) strains was found to depend on the marker that was selected. Prototrophic transformants were obtained at frequencies similar to those in the wild type control, but Spo- transformants were rare also when a spoOA::erm insertion that produces a selectable marker (ErmR) was used. The ErmR transformants obtained within the degU32(Hy) background were Spo+ and had lost the characteristics of the DegU(Hy) parental recipient strain i.e., secretion of exo-enzymes and sporulation resistance to catabolites. The spoOA::erm insertion was mapped to a location near degU. The similarities between the spoOA and degU sequences and the metabolic interferences between the mutated products which result in this unexpected recombination, are discussed.

Bacillus subtilis↗

PubMed1993

Bladder contractility and idiopathic detrusor instability in the female.

Twenty females with pure stress urinary incontinence (Group A) were studied clinically and urodynamically together with 20 stress incontinent women with idiopathic detrusor instability (Group B) and 20 controls (Group C). Forty females with the idiopathic urge syndrome, 20 with detrusor instability (motor urgency, Group D) and 20 with stable bladders (sensory urgency, Group E) were also investigated. Detrusor contractility, assessed on the basis of strength and velocity parameters derived from pressure flow data, was increased in the unstable groups. In particular, the maximum mechanical power (per unit of bladder wall surface area) generated by the contracting detrusor during voiding was higher in the unstable patients, this was also the case when estimating maximum bladder contraction velocity. No significant difference in these parameters was found in the patients with sensory urgency when compared with the controls and with the women with stress urinary incontinence, nor was there any significant difference between patients with motor urgency and the stress incontinent patients with detrusor instability. The enhanced contractile capability could be explained in the unstable stress incontinent group by a reduced threshold of stretch receptors in the urethral walls. If this were the case, urine running through the urethra at the beginning of voiding would be able to activate a urethrovesical reflex which may augment micturition contractions. In the group with the idiopathic urge syndrome one could speculate that sensory and motor urgency are due to the same neurological disorder (i.e. possibly a reduction in a tonic inhibitory or modulatory device) that would affect detrusor mechanics at different levels of the nervous system, resulting in different contractile capabilities.

Female↗

PubMed1992

Urinary flow rate in benign prostatic hypertrophy in relation to the degree of obstruction of the vesical outlet.

Forty men with bladder outflow obstruction from benign prostatic hypertrophy were investigated urodynamically by medium-fill water cystometry and pressure flow study. The most obstructed patients proved to be unstable. A positive link was found between the degree of obstruction, as assessed by the opening pressure (i.e. the detrusor pressure needed to start micturition), and the maximum mechanical power generated by the contracting bladder during voiding. What seems most striking, is that neither detrusor contraction velocity nor the urine flow rate fully mirrored the degree of obstruction--i.e. the opening pressure and the maximum contraction speed did not show a negative correlation, but rather a weak (though insignificant) positive link, and the flow rate decreased only slightly (not significantly) when obstruction increased. Such a surprising observation could be explained by the fact that prostatic obstruction produces both collagen infiltration into the bladder muscle (this affecting the spread of the depolarisation wave) and, at the same time, denervation supersensitivity. The latter actually yields a decrease in electrical resistance between the detrusor smooth muscle cells (and thereby an enhanced synchronisation of the detrusor contraction), which might be only partly cancelled by the effects of collagenosis.

Aged↗

PubMed1991

Dynamics of micturition in benign prostatic hypertrophy patients with compensated obstruction of the vesical outlet: a denervation supersensitivity-related energy-saving mechanism.

Infravesical obstruction was assessed by pressure flow study in 40 benign prostatic hypertrophy patients with a fully compensated bladder (20 stable and 20 unstable). The degree of obstruction was defined by the minimum contraction strength needed by the detrusor to start the urinary flow (opening contraction power). There were significant positive correlations among opening contraction power, maximum flow rate and maximum external voiding power, and a negative correlation between opening contraction power and voiding duration (r = -0.54, p less than 0.001). Such features suggest a decreased electrical resistance between the detrusor smooth muscle cells (due to an obstruction-related state of denervation supersensitivity) and would mirror an energy-saving mechanism. This probably works only when there is no heavy detrusor collagenosis upsetting the depolarization wave. Within physiological muscle mechanical limits, severely obstructed bladders could thus empty completely despite even highly increased amounts of work needed per unit of volume voided.

Aged↗

PubMed1990

Acceleration of flow rate as a screening test for detrusor instability in women with stress incontinence.

Forty females with urinary stress incontinence (mean age 52 +/- 10 years) and 20 age-matched controls (mean age 49 +/- 15 years) underwent complete urodynamic evaluation. In the former group, all patients complained of irritative bladder symptoms (frequency, nocturia, urgency) and 20 of them (Group B) showed detrusor instability (DI); in the other 20 (Group A) a final urodynamic diagnosis of genuine stress incontinence (GSI) was made. Instability was not apparent in Group B at standard filling cystometry, but had to be elicited through aggressively stressing the bladder by provocation tests. In all women the acceleration of flow rate (a, in ml/s2) was calculated from free flow uroflowmetry as the ratio of peak flow divided by the time to peak flow. This parameter did not differ significantly in GSI patients when compared with controls but proved higher in the DI group than in either the controls or the GSI patients. It was concluded that measuring the acceleration of flow rate is a simple and reliable test which improves the accuracy of diagnosis of detrusor instability in stress incontinent women.

Adult↗

PubMed1990

Acceleration of flow rate in obstructive detrusor instability.

The acceleration of flow rate (a) was calculated from spontaneous free flow uroflowmetry in 86 males with bladder outflow obstruction due to benign prostatic hypertrophy. Forty patients had stable bladders and 46 had detrusor instability. The parameter a was also determined in 30 controls. All of the obstructed patients had lower values of a than the controls but patients with detrusor instability tended to show a higher acceleration of flow rate than those with stable bladders. In individual cases, however, parameter a was unreliable in distinguishing stable from unstable patients.

Adult↗

PubMed1990

Opening contraction energy in prostatic (compressive) obstruction.

The opening contraction energy (Eop), i.e. the energy expended by the detrusor in the opening phase of micturition, was measured in 70 males (mean age 63 +/- 9 years) with bladder outflow obstruction (compressive obstruction) due to benign prostatic hypertrophy. Significant correlations (p less than 0.001) were found between Eop and the maximum external voiding power developed by the detrusor, Wext max (rs = -0.57), between Wext max and the fraction of bladder volume voided, VV% (rs = 0.65), and between Eop and VV% (rs = -0.77) - which suggests that increasing values of Eop affect the energy which the detrusor can supply for completion and termination of voiding. It then seems the parameter Eop would be able to assess not only the opening phase of micturition, but the emptying phase as well - the greater Eop (i.e. the greater the work needed to unfold the urethral lumen and start urine flow), the lesser the muscle mechanical capability of the urinary bladder to completely void. Thus, we eventually believe that calculating the parameter Eop may prove to be a complete, though indirect, method of quantifying the degree of prostatic (compressive) obstruction of the vesical outlet by a single numerical index.

Aged↗

PubMed1988

Detrusor instability and bladder outflow obstruction. Evidence for a correlation between the severity of obstruction and the presence of instability.

Forty patients with bladder outflow obstruction due to benign prostatic hypertrophy were assessed by means of symptom analysis, rectal examination, intravenous urography and/or cystoscopy, medium-fill water cystometry and pressure flow study. No significant correlation was found between the severity of obstruction and the degree of instability, but the occurrence of instability did correlate with the degree of obstruction. This latter conclusion, though logical, had not been proved before, and was achieved by means of a new urodynamic parameter.

Aged↗

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