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Biomedical subjects

A Lais

Publications and source records attributed to A Lais.

At least 37 records · Page 2Linked to original sources
PubMed1993

Female genito-urethroplasty and submucosal periurethral collagen injection as adjunctive procedures for continence in the exstrophy-epispadias complex. Preliminary results.

Continence is the main goal in the treatment of patients with bladder exstrophy and prognosis is necessarily long-term. Over an 8-year period, 44 patients presented with bladder exstrophy and/or incontinent epispadias. Twenty-five bladder closures (7 secondary), 23 male urethroplasties, 19 bladder neck (BN) reconstructions and 6 bladder augmentations were performed in these patients. In 18 children 2 additional procedures were employed in the last 3 years: female genito-urethroplasty (15) and submucosal periurethral collagen injection (11). Eight children underwent both procedures. Genito-urethroplasty and collagen injection were performed before BN reconstruction in 6 and 5 cases respectively, in order to increase bladder outlet resistance. The submucosal injection was performed at 3, 9 and 12 o'clock in the BN or sphincteric urethra, using 0.75 to 2.5 ml of cross-linked bovine collagen. Continence in the children who underwent the complete staged reconstruction was good in 58%, fair in 32% and poor in 11%. Following female genito-urethroplasty and periurethral collagen injection, bladder capacities increased by 25%. These complementary procedures are effective in increasing outlet resistance and bladder capacity in patients with exstrophy and/or epispadias; they may improve continence and lessen the need for further bladder augmentation.

Bladder Exstrophy↗
PubMed1993

Effects of gabapentin on release of gamma-aminobutyric acid from slices of rat neostriatum.

The gamma-aminobutyric acid (GABA) analogue gabapentin (CAS 60142-96-3) has a strong anticonvulsant activity in patients, but its mechanism of action is unknown. In the present study, the effect of gabapentin was tested on the release of [3H]GABA from neostriatal slices incubated in vitro. Gabapentin displayed a bell-shaped concentration-response curve. When used at the therapeutically relevant concentration of 1 mumol/l, it nearly doubled the release of [3H]GABA, while it was without effects at concentrations of 0.1 and 10 mumol/l, respectively. The enhancing effect was blocked by the GABAA receptor antagonists picrotoxin (5 mumol/l) and bicucullin (100 mumol/l). When the slices were pre-incubated with the agonist muscimol (1 mumol/l) to occupy the GABAA receptors, 1 mumol/l gabapentin no longer enhanced the release of [3H]GABA. It is concluded that gabapentin can enhance the release of [3H]GABA, when used at a therapeutically relevant concentration. GABAA receptors are involved in this effect which may contribute to the agent's anticonvulsant activity.

Acetates↗
PubMed1992

The response of the fetal kidney to obstruction.

In a fetal ovine model the renal effects of different anatomic levels of fetal urinary obstruction were studied. Parameters of prenatal renal growth and differentiation were characterized and correlated with the patterns of renal response to in utero obstruction. Complete ureteral or urethral obstruction was produced in the sheep fetus at 55 to 60 days of gestation. Animals were delivered and sacrificed at near term (140 days), and the kidneys were removed and prepared for analysis. Parameters examined included weight, histology, glomerular number and total surface area, as well as urinary sodium, creatinine, osmolarity and N-acetyl glucosaminidase. Three patterns of response were identified, producing hydronephrotic, cystic or dysgenetic kidneys. Hydronephrotic kidneys were usually the result of bladder outlet obstruction or ureteral obstruction with spontaneous urinary decompression. These kidneys were large (20.7 gm. versus normal 10.8 gm., p less than 0.0001), with thinning of cortical parenchyma that was structurally intact. Glomerular number and surface area were normal. Cystic kidneys were large (14.2 gm., p less than 0.05) with grossly visible cysts and an effaced medulla. Cortical structure was distorted by cysts but basic elements were intact. Glomerular number and surface area were not reduced. Dysgenetic kidneys were small (3.9 gm., p less than 0.0001) with markedly abnormal cortical structure and little recognizable medulla. Histological elements similar to fetal structures were present, including cuboidal/columnar tubular epithelium and peritubular mesenchymal collars. Glomerular number and surface area were significantly less than normal (p less than 0.001). The kidneys contralateral to unilaterally obstructed kidneys were significantly larger than normal (16.2 gm., p less than 0.0001), with normal histology, glomerular number and surface area, indicating in utero contralateral renal hypertrophy. Urinary sodium was variably affected in the hydronephrotic kidneys and was identical to plasma in the dysgenetic kidneys. These results indicate the technical feasibility of in utero models of urinary obstruction. Renal growth and patterns of differentiation were markedly affected by in utero obstruction. They should be a major focus in the investigation of congenital obstructive uropathy, since normal processes of renal growth and differentiation form the basis for postnatal function.

Animals↗
PubMed1992

Impact of primary surgical approach in the management of the impalpable testis.

There is no univoque opinion about the place of preoperative studies in non-palpable testes. During a 6.5-year period, we operated on 296 impalpable testes in prepubertal boys. A combined inguinal-abdominal approach was used in all cases verifying the eventual abdominal testis and its exact vascular anatomy before any manipulation of the cord was undertaken. Forty-five testes (15.2%) were canalicular, 142 (48%) were abdominal, 5 (1.7%) dysgenetic and 104 (34.1%) absent (agenesis or vanishing testis). Of the abdominal testes, 122 underwent a standard orchidopexy in dartos pouch, 11 a staged repair, 8 a Fowler-Stephens operation and 1 orchiectomy. All means of investigation for impalpable testes are either unreliable, too expensive or too invasive for routine use, and in most cases, a surgical exploration has to be performed anyway. The primary surgical approach has the most favorable cost/benefit ratio, being diagnostic and therapeutic at one time. Provided the exploration is performed correctly, all the advantages of previous laparoscopy can be achieved with surgery alone.

Adolescent↗
PubMed1991

Effects of p-chloroamphetamine on release of [3H]gamma-aminobutyric acid from slices of rat caudate-putamen.

The effect of endogenous serotonin on the release of [3H]gamma-aminobutyric acid ([3H]GABA) from slices of rat caudate-putamen was studied. p-Chloroamphetamine was used to release endogenous serotonin. p-Chloroamphetamine (100 nM) enhanced the release of [3H]GABA induced by 20 mM K+, while 1000 nM p-chloroamphetamine decreased it. The 5-HT3 receptor antagonists ICS 205-930 (50 nM) and MDL 72222 (100 nM) prevented this facilitation caused by 100 nM p-chloroamphetamine. ICS 205-903 (50 nM), when used alone, reduced the release of [3H]GABA caused by 23 mM K+. This finding confirmed the hypothesis that endogenous serotonin can enhance the release of [3H]GABA via 5-HT3 receptors. In contrast, an effect of 5-HT1 and 5-HT2 receptors could not be clearly established. It is likely that the release of endogenous GABA from striatonigral GABA neurons may also be affected by serotonin via 5-HT3 receptors.

Animals↗
PubMed1991

Effects of unilateral cortex lesions on gene expression of rat cortical cholecystokinin neurons.

In rat neocortex, the gene encoding preprocholecystokinin is expressed in interneurons which also synthetize gamma-aminobutyric acid. An injury to the meninges and the underlying cortex increased the concentration of mRNA coding for preprocholecystokinin in all ipsilateral cortical areas. Simultaneous treatment of the rats with the anti-inflammatory agent diclofenac did not affect the injury-induced change in gene expression indicating that inflammatory processes were not involved. The injury also enhanced the expression of the immediate early gene c-fos in the ipsilateral cortex in a time-dependent manner. There was an increase in c-fos mRNA 1 h after the operation, which was no longer observed 3 h later. Twenty-four hours after the operation, cells containing c-fos mRNA were found in cortical layers II, III, V and VI. The neurons which showed an increased expression of preprocholecystokinin were also in these layers. The N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 prevented the injury-induced increases in both preprocholecystokinin and c-fos gene expression, indicating that stimulation of this glutamate receptor subtype may initiate the changes in expression of both genes. It is hypothetized that the immediate early gene c-fos is activated first and this then leads to the increase in preprocholecystokinin mRNA.

Animals↗
PubMed1991

Effectiveness of trigonoplasty to treat primary vesicoureteral reflux.

Among the surgical procedures to treat vesicoureteral reflux trigonoplasty is a conservative technique that preserves the integrity of the vesicoureteral junction. Since its introduction in 1984 by Gil Vernet it gained only little attention in small series. Between 1986 and 1989 we performed trigonoplasty in 51 children 4 months to 13 years old, of whom 47 had primary vesicoureteral reflux. Our study includes 44 patients who have sufficient followup and 69 refluxing units. Reflux was grade II in 25 units, grade III in 39 and grade IV in 5. Patients were arbitrarily divided into 2 age groups: less than (13) and greater than (31) 3 years old. All children underwent standard preoperative assessment. The operation, with technical modifications (absorbable sutures in all cases and muscular incision added in 12), was performed after failed conservative treatment in all patients except 5 who were operated on at diagnosis. Surgery was successful in 97.7% of the patients and in 92.3% of the children less than 3 years old. The only recurrence was noted on 1 side of a 2-year-old child who had had grade IV bilateral reflux. Considering that reimplantation threatens the integrity of the vesicoureteral junction and endoscopic injections still have unclear side effects, indications for trigonoplasty can be extended to higher grades of reflux if ureteral tapering is not required and a sufficient intramural length of ureter can be obtained.

Adolescent↗
PubMed1991

Distal hypospadias repair by urethral sliding advancement and Y-V glanuloplasty.

Different techniques are available today for repairing distal (coronal and subcoronal) hypospadias but none is universally recommended. We developed the technique of a distal urethral advancement glanuloplasty operation that is specifically intended for distal hypospadias repair even with mild chordee. Mobilization of the distal urethra is performed for 1.0 to 1.5 cm. after subcoronal circumcision and a deep Y-shaped incision of the glans. The mobilized urethra is dorsally split and slid forward to the tip of the dart of the glans previously prepared. Glanuloplasty is performed using the 2 lateral flaps of glans tissue. From January 1987 to December 1989 we used this technique in 74 cases of distal hypospadias with mild or no chordee (patient age 18 months to 9 years, mean 3.5 years). A transurethral catheter was left indwelling for 3 to 4 days. Hospitalization time was 5 (plus or minus 1.5) days. Results after 4 to 40 months of followup are encouraging cosmetically and functionally. All patients were cured. In 3 cases (4%) meatal stenoses occurred requiring meatotomy and in 8 boys meatal dilations were performed on an outpatient basis. In 1 case (1.3%) a fistula developed, which was subsequently repaired without further complications. This operation may be successfully used in most cases of distal hypospadias, with a low complication rate and excellent cosmetic results. It also may be used if mild chordee is present, thus reducing the indications for flip-flap urethroplasty in those cases when meatal advancement procedures may not be effective.

Child↗
PubMed1991

Early diagnosis and treatment of spinal dysraphism to prevent urinary incontinence.

Spinal dysraphism represents a very rare congenital anomaly of the spinal cord and cauda equina, often associated with cutaneous sacral lesions. This condition results in distorsion of neural tissue, possibly leading to vesical dysfunction and urinary incontinence. A series of 12 children with spinal dysraphism (4 lipomeningoceles with tethered cord, 3 tight filum terminale, 2 dermal sinuses, 2 arachnoid cysts, 1 anterior meningocele) observed during the last 6 years is presented. The patients are divided into two groups: group A includes 5 infants (age range 4 months-2 years) and group B 7 older children (4-12 years). All 7 patients of group B were referred for urinary incontinence as their chief complaint; only 1 had evidence of a skin lesion while 3 had a club foot. In group A, 4 had skin lesions (2 asymptomatic and 2 dermal sinuses referred after several episodes of meningitis) and the 5th child had a club foot. The diagnosis was made by myelo-CT scan in the earlier 4 and by magnetic resonance imaging in the more recent 8 cases. All 12 children were operated. In group B, the patients' urinary incontinence persisted but did not worsen (3 were stable and 4 had slightly improved); in group A, 2 were dry (follow-up greater than 2 years), 1 could not be accurately evaluated because he was less than 2 years of age, and the 2 who suffered from meningitis were incontinent. Early diagnosis and neurosurgical treatment of spinal dysraphism may prevent urinary incontinence. Accurate urodynamic, neurophysiologic, and neuroradiologic evaluation of children with severe voiding anomalies or club foot is recommended even if no lumbosacral cutaneous lesions are present.

Child↗
PubMed1991

Testicular prosthesis in children: a simplified insertion technique.

A simplified technique for testicular prosthesis insertion in children is presented. The prosthetic testicle is inserted through an inguinal incision and slid into the scrotum. It is kept in position by closing the scrotal entrance with one suture applied through a small skin incision at the scrotal root. This technique has proved to be safe and reliable with regard to extrusions and migrations of the prostheses, as well as other complications.

Child↗
PubMed1990

Endoscopic manipulation of ureteral calculi in children by rigid operative ureterorenoscopy.

To date, rigid operative ureterorenoscopy with ultrasound lithotripsy for the treatment of ureteral calculi has been performed only in adults or older children. The size of the instrument with the working channel for the ultrasound probe has been considered unsuitable for delicate anatomical structures, such as those of children younger than 4 years. We performed 8 ureterorenoscopic examinations in 7 patients (3 boys) 3 to 8 years old and have demonstrated that the 11.5F ureteroscope can be inserted without difficulty into the ureteral meatus of a 3-year-old boy. Introduction of the instrument is facilitated by the use of the Perez-Castro irrigation pump. This procedure does not lead to any urethral or ureteral damage, nor is vesicoureteral reflux shown on a postoperative cystogram. This technique allows extracorporeal shock wave lithotripsy to be extended also to small children, offering the possibility of easy and successful management of any residual steinstrasse.

Child↗
PubMed1989

[Urinary incontinence in children: etiopathogenesis and clinical aspects].

Urinary incontinence can only be considered a disease after a child has completely acquired spinal mechanisms of vesico-sphincteric nervous control. This normally happens for the majority of children between two and two-and-a-half years of age regarding voluntary daytime control, while complete night-time control is obtained in 90% of cases within the fourth year. By urinary incontinence we mean an involuntary leak of urine through the bladder neck. This can vary from an occasional leakage consisting of a few drops to a continuous and uncontrollable stream of urine. From 1981 to 1986 we evaluated, in the Pediatric Urological Service at Bambino Gesù Hospital, Rome, 426 children suffering from urinary incontinence. According to the etiology we divided the patients into two large groups: 1) patients with incontinence due to anatomic causes 56 (13%); 2) patients with incontinence due to dysfunctional causes 370 (87%).

Child, Preschool↗
PubMed1986

Fiber loss is primary and multifocal in sural nerves in diabetic polyneuropathy.

Pathological, morphometric, and teased fiber studies of sural nerve from 36 diabetic patients with (n = 32) and without (n = 4) neuropathy and from 47 healthy subjects provide evidence that in diabetic polyneuropathy: (1) fiber loss is primary; (2) demyelination and remyelination with or without onion bulb formation are secondary; (3) remaining fibers, on average, have the same ratio of small to large fibers as in healthy individuals, but with a greatly increased variability; and (4) the spatial distribution of fiber loss is both diffuse and multifocal. Criteria developed during the study of experimental models of ischemic neuropathy were employed to assess whether ischemic nerve damage had occurred in diabetic polyneuropathy. We conclude that there is increasing evidence that microvascular pathological abnormality and ischemia may be involved in the pathogenesis of human diabetic polyneuropathy. Cases with selective loss of small or large afferent fibers are probably extremes of a normal distribution and not different disorders.

Adult↗
PubMed1986

The spatial distribution of fiber loss in diabetic polyneuropathy suggests ischemia.

Characterization and quantitation of the spatial distribution of pathological abnormalities along the length of nerves may be helpful in understanding the underlying mechanisms of diabetic polyneuropathy. To this end, by examining transverse sections of nerve roots and proximal-to-distal levels of lower limb nerves in 9 controls and 15 diabetic patients with polyneuropathy, we have determined the myelinated fiber (MF) number, size distribution, median diameter, and variability of density (MFs/mm2) among frames and among fascicles. Even in cases with mild polyneuropathy, fiber loss, a decrease in the median diameter, and an increase in the variability of density among frames and among fascicles began in proximal nerve and extended to distal levels. Multifocal fiber loss along the length of nerves and sprouting provide the best explanation for these findings. The pattern is dissimilar from that observed in diffuse metabolic disease of Schwann cells, neuronal degeneration, and dying-back neuropathy, but like that found in experimental ischemic neuropathy induced by embolization of nerve capillaries.

Adult↗
PubMed1986

Ketanserin (S2-receptor blocking agents), hypertension and chronic alcoholism.

Ketanserin is a pure antagonist of serotonin S2-receptors, in blood vessels, platelets and bronchial tissue. Ketanserin has been suggested as hypotensive drug in man, but it shows as well a specific activity on platelet aggregation. An increased incidence of hypertension, of unknown origin, has been found in patients with chronic alcoholism: hypotheses have been made upon an increased incretion of catecholamines and a greater sensitivity of blood vessels' receptors to their action. The data from the present study of eleven patients show that these subjects had an increased platelet activity and ketanserin administration was effective in allowing both the blood pressure levels and platelet activity to resume their normal range. This drug is thus suggested, for its pharmacological properties, as an elective medication for hypertensive patients with chronic alcoholism.

Adult↗
PubMed1985

Peripheral axotomy induces neurofilament decrease, atrophy, demyelination and degeneration of root and fasciculus gracilis fibers.

We have recently shown that peripheral axotomy by hindlimb amputation in adult cats sequentially results in neurofilament and microtubule decrease and axonal atrophy, myelin wrinkling, myelin remodeling (de- and remyelination), more atrophy and axonal degeneration in proximal sciatic and L7 segmental nerve fibers. The neuropathologic, morphometric and teased fiber alterations in the myelinated fibers (MF) of roots and sampled levels of fasciculus gracilis in groups of adult cats 24 months after hindlimb amputation have now been studied. We found: a severe decrease of neurofilaments, axonal atrophy, myelin wrinkling, de- and remyelination and axonal loss in posterior root axons; that these morphologic abnormalities extended up the fasciculus gracilis in the appropriate territories established from degenerative studies; that the retrograde effect was less severe in ventral root fibers, although atrophy and sprouting were demonstrated here, and that the cellular sequence of retrograde atrophic degeneration of ascending axons was similar to that observed in proximal stump axons. These findings confirm that primary afferent neurons are more vulnerable to axotomy than lower motor neurons and may provide an additional explanation for the poorer functional restoration of sensory than of motor deficit after root compression and in delayed nerve reconnection. Our observations also have important implications for interpretation of neuropathologic alterations in roots and fasciculus gracilis, since the observed features may be secondary to axotomy of peripheral nerve fibers induced by disease and not evidence of a primary derangement.

Amputation, Surgical↗