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Biomedical subjects

J Bost

Publications and source records attributed to J Bost.

At least 19 recordsLinked to original sources
PubMed1999

Association between peridural scar and persistent low back pain after lumbar discectomy.

The purpose of this study was to investigate the correlation between low back pain persisting six months after first surgery for herniated lumbar intervertebral disc and the extent of peridural fibrosis present at the surgical site, as defined by magnetic resonance imaging (MRI). The 298 patients who underwent first-time, single-level unilateral discectomy for lumbar disc herniation were evaluated in a controlled, randomized, double-blind multicenter clinical trial to test the effectiveness of the scar-inhibiting device ADCON-L. Clinical assessments were conducted pre-operatively and at 1, 3, and 6-month intervals post-operatively, and included MRI scar assessment and the assessment of low back pain by visual analog scales. There were 267 patients available for low back pain assessments. The data obtained at the 6-month follow-up visit were statistically analyzed for the association between the presence of peridural scar and the persistence of low back pain. Those patients treated with ADCON-L at surgery had significantly less scar than did control patients (p = 0.007), and had less low back pain than did control patients when the pain was most severe (p = 0.047) and when the pain was assessed at the end of the day (p = 0.044). Patients with extensive scar reported continuing and debilitating low back pain more frequently than those with no or minimal scar. These findings demonstrate a direct correlation between persistent low back pain and extensive scar, since patients with increased amounts of scar had increased low back pain, regardless of their treatment group (p = 0.0003).

Chronic Disease↗
PubMed1998

Outcome after microdiscectomy: results of a prospective single institutional study.

BACKGROUND: Although lumbar microdiscectomy is one of the most frequently performed spinal procedures, little consensus exists in the literature regarding results. Whereas retrospective reports boast success rates as high as 98%, prospective studies are less sanguine with statistics in the 73-77% range. METHODS: Prospective single-institution outcome study of all patients undergoing virgin unilateral single-level microdiscectomies by study surgeons November 1990 to March 1992. Outcome determined by patient-reported responses to mail questionnaire or phone interview by a disinterested party. RESULTS: There were 374 patients operated on, average age 42.4 years with mean length of symptoms 9.4 months, and 31.5% were Workman's Compensation cases. Total complication rate was less than 4%, and follow-up was accomplished for 86% of the patients. Overall success rate was 74% using a strict combination of patient-reported pain relief, work status not affected, absence of narcotic use, and satisfaction with the procedure. Using a multivariate logistic regression analysis, only Workman's Compensation claim and length of symptoms (>6 months) were related to success, with a positive outcome in 86% of non-Compensation patients with brief symptoms contrasting with 29% in Compensation cases of greater than 6 months duration. CONCLUSIONS: A prospective analysis of the frequency of success after microdiscectomy yields results lower than anticipated based on retrospective studies and finds success related to the non-anatomic factors of length of symptoms and Workman's Compensation claims.

Adult↗
PubMed1995

Better functional status in American than Canadian patients with heart disease: an effect of medical care?

OBJECTIVES: This study compared functional status in Americans and Canadians with and without prior symptoms of heart disease to separate the effects of medical care from nonmedical factors. BACKGROUND: Coronary angiography and revascularization are used more often in the United States than in Canada, yet rates of mortality and myocardial infarction are similar in the two countries. Recent data suggest that functional status after myocardial infarction is better among Americans than Canadians, but it is uncertain whether this difference is due to medical care or nonmedical factors. METHODS: Quality of life was measured in patients enrolled in seven American and one Canadian site in the Bypass Angioplasty Revascularization Investigation. Prior symptoms of heart disease were defined as angina, myocardial infarction or congestive heart failure before the episode of illness leading to randomization. Functional status was measured with the Duke Activity Status Index and overall emotional and social health using Medical Outcome Study measures on the basis of patient status before the index episode of acute ischemic heart disease. RESULTS: Quality of life was generally better in the 934 Americans than in the 278 Canadians, with overall health rated as excellent or very good in 30% of Americans versus 20% of Canadians (p = 0.0001), higher median Duke Activity Status Index scores (16 vs. 13.5, p = 0.03) but equivalent emotional health (76 vs. 76, p = 0.74) and social health scores (100 vs. 80, p = 0.07). Among the 350 patients without prior symptoms of heart disease, Americans and Canadians had similar overall health, Duke Activity Status Index and emotional and social health scores. However, of the 860 patients with previous symptoms of heart disease, Americans had higher overall health (p = 0.0001) and Duke Activity Status Index scores (p = 0.0008) but similar emotional and social health scores. The results were essentially unchanged after statistical adjustment for potential confounding factors. CONCLUSIONS: The functional status of patients without prior symptoms of heart disease is similar in Americans and Canadians. However, among patients with previous symptomatic heart disease, functional status is higher in Americans than in Canadians. This difference may be due to different patterns of medical management of heart disease in the two countries.

Aged↗
PubMed1986

[Urea feeding of sheep on a diet rich in proteins: effects on urinary secretion].

Ten ewes kept on a high protein level diet were fed water solutions of urea (0.25 g/kg). Blood urea, urine volume and renal urea excretion were determined thereafter. A long lasting increment of blood urea level was observed as well as an increased urine volume with a lowered urinary osmotic pressure. Moreover, urea clearance was significantly decreased in spite of the increased amount of urea excreted by the kidney. A negative correlation between urea clearance and blood urea level could be demonstrated when the latter was higher than 0.5 g/l.

Animal Nutritional Physiological Phenomena↗
PubMed1985

[Characteristics of esophageal antiperistaltic activity in sheep].

Oesophageal motility was investigated in standing conscious sheep. A manometric method was used in four animals; two sheep, fitted with permanent electrodes at four levels, were used for oesophageal electromyography. The occurrence of retrograde peristalsis (mean speed 71,5 cm.s-1) at the beginning of every rumination cycle is reasserted. The characteristics of this activity are pointed out, with reference to normal peristalsis during the deglutition of saliva. Different types of stimulation have been compared. Retrograde peristalsis (mean speed 66 cm.s-1) can be triggered readily in non-ruminating animals by the association of two stimulations. One being oesophageal distension and the other injection of a solution prepared with some physical or chemical components of the rumen liquid. No specialized sensitive area could be demonstrated. However, facilitation is evident during reticular contractions. Retrograde waves of contraction always start from the terminal part of the thoracic oesophagus, whatever the level of stimulation.

Animals↗
PubMed1985

[Start of mastication by esophageal distension in sheep].

Oesophageal wall distension was performed on standing conscious sheep by inflating a rubber balloon at four different levels inside the cervical and thoracic oesophagus. Although no retrograde oesophageal peristalsis was ever recorded, these stimulations were always followed by a conspicuous increase of parotid saliva secretion. They frequently induced the onset of chewing movements, whatever the level of the oesophageal distension. The cyclical reticular activity does not bear any relationship to the occurrence of the chewing movements. The masticatory response could be either of the "ON" or "ON - OFF" type, but most often of the "OFF" type. The response to thoracic oesophageal distension was suppressed by mid-cervical anaesthetic blockage of vagal conduction. A possible involvement of any sort of stimulation of the oral cavity was thus ruled out. The masticatory response to oesophageal distension is a reflex mechanism whose afferent pathway from the distal part lies in the vagal trunk. Such a reflex may participate early in the initiation of chewing movements during rumination, prior to the arrival of the regurgitated bolus into the mouth.

Animals↗
PubMed1984

[Origin of the secondary peristalsis of the esophagus in sheep].

Manometric and electromyographic methods were used for investigating oesophageal motor activity in conscious sheep. A contraction wave, the so-called "secondary peristalsis", was readily evoked by means of the fast inflation of a rubber balloon distending the oesophagus. This peristaltic wave travels onto the cardia at the same speed as the primary deglutitive peristalsis (28 m X sec-1, approximately). In that particular species, whose oesophageal muscular coat is all along entirely made of striated fibers, secondary peristalsis is always initiated at the origin of the cervical oesophagus, whatever the site, cervical or thoracic, of the distension.

Animals↗
PubMed1983

[Autonomic effects of scaritoxin in the cat and guinea pig. Cardiac protection by an anti-arrhythmia agent].

A purified extract from the muscles of the fish Scarus gibbus (93% scaritoxin and 7% ciguatoxin) was tried on anesthetized cats and isolated guinea-pig atria. Intra-venous injection to cats (10, 20 and 40 mg/kg) induced deep respiratory depression, inhibition of duodenal contractions, increased salivary secretion, mydriasis and lacrymal secretion. Heart rate was slowed by 17 to 44 per cent. Impaired cardiac conduction led to different types of blocks. On the contrary, cardiac excitability was enhanced, as evidenced by the occurence of many auricular and mostly ventricular extra-systoles, often evolving into long periods of ventricular paroxysmal tachycardia. The rate of contraction of isolated guinea-pig atria was equally depressed and this effect was antagonized by atropine. The duration of the refractory period was shortened; an inotropic effect was observed and the action of acetylcholine was potentiated by the toxin. Cholinesterase inhibition by scaritoxin, previously mentioned in other papers, is thus evidenced. Mydriasis and duodenal inhibition may be tentatively explained by a nicotinic effect on the sympatheticoadrenal system. This mechanism may be responsible for cardiac inotropic action and increased excitability. Other mechanisms may be suggested, including a possible digitalis-like effect due to a cyclopentanone ring in the scaritoxin molecule. Interestingly, intra-venous injections of the antiarrythmic drug procainamide (20 to 30 mg/kg) could either prevent or reverse the signs of cardiac hyperexcitability in the anesthetized cat. However, death results usually from respiratory depression, the intimate mechanism of which is not yet known.

Animals↗
PubMed1981

[Prandial stimulation of reticular movements in sheep: cephalic phase and oral reflex (author's transl)].

Acceleration of reticular contractions when chewing feed (oral reflex of the reticulum, ORR) has been well documented for many years. The aim of the present investigation was to study the evolution of this reflex throughout the meal period. A possible triggering effect of drinking water was also investigated. Reticular contractions and chewing movements were simultaneously recorded from four sheep by means of permanent reticular wire electrodes and foam rubber balloons fastened below the lower jaw. Records were drawn before and during presentation of feed, then during the meal which followed. Similar records were drawn while sheep were drinking during intervals between feeding periods. In every case, intensity of mastication decreases from beginning up to the end of the feeding period. This decrease is paralleled by a slope of reticular frequency, which is very high at the beginning of the meal. The significant correlation between the two phenomena suggests that the decrease of the ORR results from a lesser stimulation of oral mechanoreceptors. Reticular movements are obviously accelerated during isolated drinking periods. Existence of a true cephalic phase of prandial reticular stimulation is evidenced by a moderate acceleration on the sole presentation of feed.

Animals↗
PubMed1980

[Effects of intracerebroventricular injections of nalorphine on feeding behaviour and rumination in sheep (author's transl)].

Two sheep were fitted with permanent cannulus in the first cerebral ventricule and permanent electrodes were stitched to the wall of the reticulum. They were housed in individual pens and fed lucern pellets twice a day (total duration 1.30 hour) at fixed hours. Food intake was weighed. Chewing movements were recorded permanently by means of a submandibular balloon. Reticular motility was recorded by electromyography during feeding periods. Feeding behaviour and rumination were previously recorded during two control periods. No treatment was applied during the first control period of 6 days (Ta). During the second one (Tb), daily intracerebroventricular (ICV) injections of saline (0.2 ml)) were given for 4 consecutive days. During the following 4 days (Na period), the sheep received isovolumic ICV injections of nalorphine (1 mg per day). Saline was injected again ICV for the last 4 days of the experimental period (Tc). During the period of nalorphine administration there was an important fall in the circadian percentage of rumination of one sheep and a total suppression in the other, discarding the possibility of a volumetric effect. There was also a significant decrease of food intake in the two sheep but nalorphine did not modify the frequency of reticular contractions in any case. Regarding to the general behaviour, the drug induced a general excitation with bleating and increased responsiveness to stimuli. Oral activity included compulsive and continuous chewing movement, creaking the teeth, gnawing, nipping and an apparent activity of searching food for up to 15 hours. In conclusion, nalorphine and morphine effects upon the sheep are compared. The effects of the two drugs are exactly the same regarding to the decrease of rumination and feeding intake and the modification of general behaviour, but morphine decreases markedly the reticular rhythm whereas nalorphine does not. Besides, it seems that the animals get tolerant more readily to morphine than to nalorphine.

Animal Feed↗
PubMed1979

[Vasomotor innervation of the maxillary canines of the dog].

Maxillary canine pulpar pressure was recorded on anesthetized dogs by means of a small bore cannula threaded into a hole drilled through the lateral surface of the tooth. Vasoconstriction was brought by the electrical stimulation of the cranial cervical ganglion. Vasodilation was induced by stilmulation of the pterygo-palatine ganglion. This vasodilation was inhibited by atropine. Most often, constrictor fibres follow the course of the pterygo-palatine nerve, when dilator fibres follow the infraorbital nerve. However, both sorts of fibres may be found in the infraorbital nerve.

Animals↗
PubMed1979

[The effects of non-protein-nitrogen additives on lipid and carbohydrate metabolisms in sheep (author's transl)].

The effects of NPN administration on lipid and carbohydrate metabolisms were investigated in 14 sheep. Blood non-esterified fatty acids (NEFA) are increased by intra-ruminal dosage with urea (10 g), 1 p. 1000 ammonia solution (1 l) or ammonium chloride (17.6 g). Peak values are recorded 3 to 4 hours after the injection. An early rise of NEFA and hyperglycemia are observed when ammonium chloride is injected intra-venously. The time-course of the variations of the different blood constituents (ammonia, glucose, NEFA, urea) as well as the lack of any action following intra-venous urea injections suggest that lipid mobilization is induced by the increased level of blood ammonia. The involvement of a strenghened activity of the sympathetic-adrenal system is evidenced by the increased elimination of urinary catecholamines.

Ammonia↗
PubMed1977

[Saliva ammonia and urea in the sheep. Effects of alimentary nitrogen additives (author's transl)].

The salivary elimination of ammonia and urea was studied in 4 permanently salivary duct fistulated sheep. Sheep were fed either a regular diet or the same diet with addition of non protein nitrogen (NPN). Individual saliva ammonia levels vary from 34 to 71 microgram N/100 ml. After intra-ruminal dosing with urea (10 g) or ammonia (2 g), the values may rise up to 1000 microgram N/100 ml. Saliva ammonia and blood ammonia changes follow the same direction. Daily saliva urea variations are correlated with feeding behaviour. NPN administration increases saliva urea and blood urea; both concentration curves are parallel.

Ammonia↗
PubMed1976

[Methods of determination of fluoride in trace amounts. Application to the study of the diffusion of fluoride from an amalgam in dental tissues].

The study of fluoride diffusion in dental tissues has been performed by microprobe analysis. The fluoride supply is carried out in vivo by various fluorides added to conventional amalgams. This method differs then from previous work (topical applications, electrophoresis or fluoride solutions) by the study of fluoride penetration from amalgams either in dentine or in deep enamel, which are more susceptible to caries than superficial enamel. These experiments give evidence of a fast penetration of fluoride into dental tissues, which may be characterized by an apparent diffusion coefficient of about 10(-10) cm2/s.

Dental Amalgam↗