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Biomedical subjects

J Lamarche

Publications and source records attributed to J Lamarche.

At least 19 recordsLinked to original sources
PubMed1988

Experimental allergic encephalomyelitis: a neurourological study.

To assess the neurourological disturbances produced by the perivascular inflammatory process in the acute phase of experimental allergic encephalomyelitis, we carried out a controlled study. Forty-six New Zealand male rabbits were inoculated with an encephalitogenic preparation. Twenty-seven of them developed neurological deficits in an average of 9.3 days postinoculation. A sample of 19 subjects was used as a control. The subjects were studied within 2 days after the manifestation of the first sign of encephalomyelitis. An average of eight successive cystosphincterograms were recorded. Their entire central nervous system was removed intact and suspended in 10% neutral buffered Formalin solution for 2 weeks, then cut into segments, embedded in paraffin, and finally stained with hematoxylin-eosin and Luxol Fast Blue. The results demonstrated a significant reduction of mean vesical capacity, maximum urethral pressure, and mean urethral pressure in the group with encephalomyelitis. Furthermore, we found a significant negative correlation between the average number of cellular perivascular infiltrates in the spinal sacral segment and urethral pressures. The results showed a significant negative correlation between supreamesencephalic inflammation and mean vesical capacity.

Animals↗
PubMed1988

Colonic hamartomas in tuberous sclerosis.

Twelve patients, 5 from the same family, diagnosed consecutively to suffer from tuberous sclerosis were investigated for gastrointestinal polyps. Six patients had no clinical neurologic involvement. Nine had colonic polyps: in 5 patients, these were hamartomas, in 3 patients adenomatous polyps, and the ninth patient had hamartomas and adenomatous and villoglandular polyps. Hamartomatous polyps were identical to those found in the Peutz-Jeghers syndrome. However, in 1 patient they included neural structures and in another there were angiomatous and adipous structures in addition to colitis cystica profunda. Two patients with hamartomatous polyps had normal intelligence and no clinical neurologic symptoms. The evaluation of one kindred revealed the association of hamartomatous polyps of the colon with forme fruste of tuberous sclerosis in different members, but none had the typical disease. Tuberous sclerosis should thus be considered in the differential diagnosis of hamartomatous colonic polyps. Conversely, colonic endoscopy may be a useful adjunctive test in the diagnosis of tuberous sclerosis, particularly in the incomplete varieties of disease.

Adolescent↗
PubMed1987

Pattern electroretinogram and optic nerve section in pigeons.

We studied the effect of optic nerve section on the pattern electroretinogram (PERG) of 10 pigeons. Base line PERG and flash ERG were measured prior to surgery and then one optic nerve was cut. We measured PERG at various time intervals up to 24 weeks after the section. There was a sharp drop in PERG amplitude immediately following the section. It gradually returned to normal levels in the following 24 weeks. Significant decreases in time to peak were noted at 1 and 16 weeks for 0.5 cycle per degree checks and at 1, 2 and 9 weeks for 0.25 cycle per degree checks. The ERG generated by a TV stimulus did not change in amplitude but had a shorter time to peak at 24 weeks for a high intensity stimulus and at 16, 18, 24 weeks for a low intensity stimulus. Light and electron microscopic sections (at 24 weeks) revealed an almost complete loss of nerve fibers in the optic nerve. Retinal sections revealed only a few surviving ganglion cells and a few nerve fibers. This suggests that in pigeons, PERG is not generated by ganglion cells.

Animals↗
PubMed1987

Carcinomatous neuropathy. An ultrastructural study of ten cases.

Superficial peroneal nerve biopsies were studied from 10 patients with carcinomatous neuropathy. There were 6 patients with the sensorimotor form and 4 patients with the sensory form. In both forms of neuropathy, histometric studies showed a variable loss of myelinated fibers which was generally most severe in the sensory form. In most of the cases of the sensorimotor form, ultrastructural studies showed segmental demyelination with onion bulb formation and regeneration of myelinated fibers. In the sensory form, there was no segmental demyelination, the regeneration of myelinated fibers was minimal and all the cases showed a loss of unmyelinated fibers. In sensory neuropathy, the histometric and ultrastructural changes reflect the massive acute destruction of ganglion cells in the dorsal root ganglia. In sensorimotor neuropathy, the alterations indicate a slowly progressive degenerating process in which both axonal degeneration and segmental demyelination occurred.

Aged↗
PubMed1985

The ventilatory response to hypoxia in the newborn lamb after carotid body denervation.

Neonates of various species including lambs respond to hypoxia by a transient hyperventilation followed by a VE depression (diphasic response). To better delineate the role of the carotid chemoreceptors and that of the central depressive/inhibitive effect of hypoxia on minute ventilation, we have studied the VE response of 4-day-old carotid body-deprived lambs (CBD) during successive exposure to moderate and severe (0.12 and 0.07 FIO2) hypoxia. The carotid body denervation was done to abolish most of the chemoreceptor stimulating effect on VE during hypoxia and to allow for central depression/inhibition of VE during hypoxia. In the CBD lambs, baseline VE was 461 +/- 81 (SE) ml X (kg X min)-1. It increased to 532 +/- 79 ml X (kg X min)-1 and to 541 +/- 75 ml X (kg X min)-1, to 0.12 FIO2 and 0.07 FIO2. These VE increases did not reach level of significance (P greater than 0.05). After 2-5 min of both levels of hypoxia VE dropped respectively to 460 +/- 60 ml X (kg X min)-1 and to 459 +/- 38 ml X (kg X min)-1. No marked ventilatory depressions were noted but VE had only returned to baseline. It is concluded that, in the denervated newborn lamb, the centrally mediated depressive effect of hypoxia is small and not sufficient to explain the diphasic VE response of the intact lamb to steady state hypoxia. Analysis of the magnitude of the hyperventilation and the VE damping pre-hypoxic levels occurring with sustained hypoxia in newborns of various species suggests that the immaturity of the O2-sensitive chemoreceptor rather than the central effect of hypoxia is the determinant factor of the diphasic response of newborn mammals to hypoxic hypoxia.

Animals↗
PubMed1985

Postnatal maturation of respiration in intact and carotid body-chemodenervated lambs.

The contribution of the carotid body chemoreceptor to postnatal maturation of breathing was evaluated in lambs from 7 to 70 days of age. The study was conducted by comparing the eupneic ventilation and resting pneumograms in intact conscious lambs with those of lambs that were carotid body chemodenervated (CBD) at birth. In comparison to the 1-wk-old intact lambs, the CBD lambs had significant decreases in minute ventilation (VE, 313 vs. 517 ml/kg), tidal volume (VT, 7.2 vs. 10.5 ml/kg), respiratory rate (f, 44 vs. 51 breaths/min), and occlusion pressure (P0.1, 2.8 vs. 7.2 cmH2O). Arterial PO2's were 59 vs. 75 Torr (P less than 0.05) and arterial PCO2's 47 vs. 36 Torr (P less than 0.05), respectively, in CBD and intact lambs. In intact lambs from 7 to 70 days, resting VE decreased progressively from 517 to 274 ml/kg (P less than 0.01) due to a fall in VT, mean inspiratory flow (VT/TI), and f, whereas the ratio of inspiratory time to total breath duration remained constant. P0.1 decreased from 7.2 to 3.9 cmH2O from 7 to 42 days. In contrast the CBD lambs experienced only minimal changes in VE, VT, VT/TI, and f during the same period. VE only decreased from 313 to 218 and P0.1 from 2.8 to 2.4 cmH2O. In contrast to that of intact lambs the resting pneumogram of CBD lambs remained relatively fixed from 7 to 70 days. Three CBD lambs died unexpectedly, without apparent cause, in the 4th and 5th wk of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Sympathetic uveitis 66 years after injury.

We report a case of sympathetic uveitis occurring 66 years after perforating trauma to the other eye. To our knowledge this is the longest interval ever cited in the literature.

Aged↗
PubMed1983

Necrosis as a prognostic criterion in malignant supratentorial, astrocytic gliomas.

Surgical specimens of malignant, supratentorial, astrocytic gliomas from 503 patients randomized on an RTOG-ECOG treatment protocol were examined by central pathologic review. The diagnosis of glioblastoma multiforme (GBM) was made only when one or more foci of coagulation necrosis involving astrocytic tumor cells were identified histologically. Malignant astrocytic neoplasms without necrosis were classified as astrocytoma with atypical or anaplastic features (AAF). The median survival stratifying for treatment for patients with GBM was eight months compared to 28 months for patients with AAF. In most cases the specimens were received with a Kernohan grade. On the basis of these grades, patients with astrocytoma Grade 3 had a median survival of ten months as compared to a median survival of nine months for those with astrocytoma Grade 4. Observations demonstrate that necrosis is a reliable, decisive prognostic factor associated with malignant, supratentorial, astrocytic gliomas. The Kernohan system is of limited value in assessing prognosis for this group of tumors.

Aged↗
PubMed1983

Constipation with colonic inertia. A manifestation of systemic disease?

Transit of radiopaque markers was delayed in the ascending colon of 51 females and 3 males treated for severe idiopathic constipation. Onset of symptoms was between age 10 and 20 in more than half of the patients. Eighteen percent had previously undergone unnecessary laparotomy for large bowel pseudoobstruction. Stool frequency ranged from 1 stool every three days to 1 every 2 months. Twenty-six percent suffered from fecal incontinence. In addition, 30% had orthostatic hypotension and 15% galactorrhea of idiopathic origin. Patients had a higher than normal anal pressure (P less than 0.001). They all had a rectoanal inhibitory reflex, but it was abnormal in 76%. In the upper esophageal sphincter, resting pressure was higher (P less than 0.02), and coordination poorer (P less than 0.05) than in normal control subjects. Incidence of spontaneous tertiary contractions in the body of the esophagus was greater than normal (P less than 0.03). In the lower esophageal sphincter, resting pressure was lower (P = 0.001) and gastroesophageal gradient weaker (P = 0.05). Closing pressure of the sphincter was lower (P less than 0.001) and coordination less adequate (P less than 0.02). After subcutaneous injection of 0.035 mg/kg bethanechol, urinary bladder intraluminal pressure increased by over 15 cm H2O in 31% of patients but never did in controls, and average maximal pressure was greater (P less than 0.025). Time taken to reach peak pressure was shorter (P less than 0.01). This study provides evidence that patients who suffer from constipation with colonic inertia also have abnormal function in other hollow viscera.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

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↗
PubMed1983

[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↗
PubMed1982

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↗
PubMed1982

[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↗
PubMed1981

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↗
PubMed1981

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↗
PubMed1980

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↗