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Biomedical subjects

J Lamarche

Publications and source records attributed to J Lamarche.

34 records · Page 2Linked to original sources

Bladder and urethral dynamics in multiple sclerosis-like animal model.

Multiple sclerosis-like disease was induced in 18 rabbits by immunization with guinea pig spinal cord. The urodynamic studies conducted in the immunized rabbits showed a significantly lower maximal urethral pressure and a lower bladder capacity than those in the control group. We compared the urodynamic, clinical and histopathological parameters in the immunized rabbits. We conclude that the rabbit is an acceptable model for studying the bladder and urethral dynamics during various phases of experimental allergic encephalomyelitis (multiple sclerosis-like disease).

Anesthetics↗

[Vesicourethral physiology during continence and urination in cats. In vivo and in vitro studies].

The mechanisms implicated in the opening of the bladder neck during voiding are still controversial. We present a study of the reflexes of bladder, urethra and periurethral striated muscles in the cat. The study in vivo shows that a passive muscle tonus of the urethra is able to maintain the continence. During voiding, opening of the bladder outlet is done actively: contraction of the longitudinal and relaxation of the circular muscle layers of the urethra associated with detrusor contraction. There is a local reflex between the urethra, bladder and periurethral striated muscles that completes emptying of the bladder with an interrupted stream. The study in vitro confirms that the 2 muscle layers of the urethra have different innervation: the parasympathomimetic agents act on the longitudinal layer and very weakly on the circular. Both layers react to adrenergic stimulation.

Animals↗

Ultrastructural observations on spinal ganglion biopsy in Friedreich's ataxia: a preliminary report.

We report the preliminary study of a dorsal root ganglion obtained at biopsy during a surgical intervention in a patient with Friedreich's ataxia. There was an apparent decrease in the number of large myelinated fibers without necrosis, but with numerous axonal swellings consisting mainly of dense accumulated neurofilaments. Large amounts of lipofuscin were also found as well as some onion bulb formations suggesting a process of axonal atrophy.

Adult↗

[Parosteal osteogenic sarcoma: a study of four cases].

The authors present four cases of parosteal osteogenic sarcoma, which is a rare primary tumour of bone. The radiologic and histopathologic features are discussed. The discussion concerns mostly the indication for "en bloc resection" as the initial treatment with or without replacement by autogenous or homogenous bone graft. Amputation should be considered when there is local recurrence.

Adolescent↗

Facial nerve sutures: epineural vs. perineural sutures.

The orbicularis oculi branch of the facial nerve was transected in two groups of 15 cats. Following section of the nerve, a specimen was removed for histological studies; then, using microscopic techniques the epineurium was sutured (nylon 10:0) in the first group, and the perineurium in the second. They were then followed for 100 days. Results rely on clinical (complete closure of the eye), electrophysiological (summation potentials), and histological (fiber count) evaluations. Judging from the relative density and diameters of the fibers, epineural sutures result in better regeneration than perineural sutures. With the tremendous importance of the absence of tension on the suture line in mind, it seems that the technique of choice for monofascicular nerves, as in the pyramidal and tympanic segments of the facial nerve, is epineural suture. Despite the slight advantage of epineural suture over perineural suture as evidenced by histological evaluation, there was no clinical difference. The distal fascicular distribution of facial nerve fibers and their spatial distribution make perineural (fascicular) sutures the method of choice when anastomosis becomes necessary in the vertical portion and in the portion distal to the stylomastoid foramen.

Animals↗

A new approach to the study of the voiding cycle in the cat.

Physiologic studies were carried out on 51 anesthetized cats. We monitored contraction and relaxation with force displacement transducers, recording individually from bladder, longitudinal, and circular urethral smooth muscle layers; and intravesical pressure with a pressure transducer. During constant slow vesical filling with warm saline the urethral muscle tone, without increased motility, was capable of maintaining continence. At the prevoiding stage, the circular urethral muscle contracted and the longitudinal relaxed for 1 to 2 sec, which tightened the bladder neck and resulted in the creation of isovolumetric bladder pressure stage. The voiding was accomplished by bladder pressure augmentation, bladder muscle contraction, and synergic contraction of longitudinal and relaxation of circular urethral muscles. A transient urethral pressure drop preceded the urethral pressure rise of the isovolumetric stage of voiding. The smooth urethral muscle motility pattern during voiding was reproduced without fluid flow per urethrum by the inflation of a balloon in the bladder.

Animals↗

Meningo-ependymitis in Whipple's disease.

Six years after apparent complete recovery from intestinal Whipple's disease, a 56 year old man developed insidious progressive somnolence and gait ataxia. Studies showed hydrocephalus with obstruction of the aqueduct and CSF leukocytosis and elevated protein. Arachnoid biopsy during craniotomy revealed chronic inflammatory infiltration with PAS-positive macrophages. The patient died 5 years later despite two courses of antibiotic therapy. This is the first report of histologically confirmed cerebral Whipple's disease during life. Whipple's disease is a systemic infectious disorder. Cerebral involvement even in neurologically asymptomatic patients should be sought with periodic CSF cytologic studies and a search for hydrocephalus. The possibility of cerebral Whipple's disease should be considered in the presence of unexplained hydrocephalus and/or chronic inflammatory changes in the spinal fluid, especially in those with past or active intestinal disease.

Arachnoid↗