Measure-set computed tomographic analysis of internal architectures of lumbar disc. Clinical and histologic studies

Measure-set computed tomography (MSCT) scan was performed in 30 adult subjects (17 men and 13 women, mean age 42 years) and eight cadavers (five men and three women, mean age 42 years) to establish prospectively a normal CT pattern of the internal architectures of the lumbar disc. Based on the uniformity or nonuniformity of MSCT composition of the nucleus pulposus (NP) and annulus fibrosus (AF), and also on how well NP was discerned from the surrounding AF, the internal architecture could be categorized into well-defined (WD), intermediate (IM), and ill-defined (ID) types. An age and prevalence study of the categorized disc showed that, with age, the disc undergoes an architectural transformation from WD through IM to ID. In addition, 72.5% of WD-type discs and 72.1% of ID-type discs occurred in the third and fourth decades and in the sixth and seventh decades, respectively, suggesting that the former is a young form with mild degeneration and the latter an old form with advanced degeneration. Fifty-eight percent of WD-type discs and 60.4% of ID-type discs occurred at L1-3 and L4-S1 levels, respectively, regardless of age. This finding suggests the old form tends to occur at the lumbosacral junction, which is the site of maximum weight bearing in humans. The correlation of water content and histologic findings of degeneration with the three categorized disc types in cadavers showed that WD, IM, and ID discs were associated with the largest, intermediary, and least amount of water of NP, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of chronic ethanol treatment on the beta-adrenergic receptor-coupled adenylate cyclase system of mouse cerebral cortex

Chronic ingestion of ethanol, which produced tolerance and physical dependence, resulted in altered function of the cerebral cortical beta-adrenergic receptor-coupled adenylate cyclase system in mice. Although there was no change in basal adenylate cyclase activity, or in the activity of the digitonin-solubilized catalytic unit, stimulation of adenylate cyclase activity by the nonhydrolyzable guanine nucleotide analog guanylylimidodiphosphate [Gpp(NH)p] was reduced in brains of ethanol-fed animals. Ethanol added in vitro increased adenylate cyclase activity, and this enhancement, in the presence of Gpp(NH)p, was also reduced in cortical membranes of ethanol-fed mice. Furthermore, the maximal response to isoproterenol was decreased, and the EC50 for isoproterenol stimulation of adenylate cyclase activity was increased in ethanol-fed animals. The results are consistent with a qualitative or quantitative defect in the function of the stimulatory guanine nucleotide-binding protein (Ns), as well as in the beta-adrenergic receptor, after chronic ethanol exposure. In part, these changes appear to be similar to those that occur during heterologous desensitization of various receptor systems, and may be associated with dependence on or tolerance to ethanol.

Changes in central serotoninergic transmission affect clonidine analgesia in monkeys

The effects of changes in central serotoninergic transmission on clonidine analgesia were assessed in monkeys. The minimum electrical current required for producing jaw opening is referred to as the pain threshold. Pain was induced by electrical stimulation of tooth pulp afferents. In the first series of studies, intracerebroventricular administration of clonidine (5-30 micrograms) produced dose-dependent analgesia in monkeys. The clonidine-induced analgesia was abolished or attenuated by prior injection of the animals with p-chlorophenylalanine or 5,7-dihydroxytryptamine into the third cerebral ventricle. On the other hand, pretreatment of the animals by injecting 5-HT or its precursor 5-hydroxytryptophan into the cerebral ventricle potentiated the clonidine-induced analgesia in monkeys. In the second series of experiments, administration of clonidine (1-10 micrograms) into the diencephalic periventricular gray (of the anterior hypothalamic portion), the periaqueductal gray, or the dorsal raphe nuclei also produced dose-dependent analgesia in monkeys. The analgesia induced by clonidine injection into the diencephalic periventricular gray or the periaqueductal gray was effectively antagonized by pretreatment of the animals by injecting two 5-HT receptor antagonists (such as ketanserine and methysergide) into the diencephalic periventricular gray or the periaqueductal gray. The clonidine-induced analgesia in monkeys was not affected by pretreatment of the animals with injections of either ketanserine or methysergide into the dorsal raphe nuclei. The results suggest that the functional activity of central 5-HT neurons correlate well with the analgesic sensitivity of clonidine microinjected centrally. In addition, the analgesia induced by clonidine microinjected into the diencephalic periventricular gray or the periaqueductal gray was mediated by the 5-HT receptors at the site of injection.

The synthesis of immunogenic polypeptides encoded by tick-borne encephalitis virus

Tick-borne encephalitis virus codes for two major immunogenic polypeptides, one of which is the major virion envelope protein E, and the other, NV3, does not have a designated function at present. The intracellular forms of both the E and NV3 polypeptides contain at least four types of sugar residues, i.e. galactose, glucosamine, fucose and mannose. The only glycoprotein in the extracellular virion particles is E. Experiments performed in the presence of tunicamycin have demonstrated that most of these sugars are N-linked. The kinetics of synthesis of E and NV3 have been studied and both show a distinct lag period between initiation of protein synthesis and the appearance of either protein. The kinetics of synthesis of these proteins are consistent with the hypothesis that initiation of protein synthesis starts at the 5' end of a polycistronic genome but the synthesis of the E and NV3 proteins only occurs after translocation of the polyribosome complex to specific areas in the infected cell. No precursors to either the E or NV3 glycoproteins were detected. Synthesis of both glycoproteins can be detected as early as 6 h after infection and rises to a maximum at 15 h after infection.

Differential effects of ethanol on the striatal and cortical adenylate cyclase system

In the present study, effects of ethanol (EtOH) on C57/BL mouse cortical beta-adrenergic receptor coupled adenylate cyclase (AC) were shown to be different from the effects of EtOH on striatal dopaminergic-stimulated AC activity. The addition of EtOH (500 mM) increased the AC activity by 60% in cortical membrane and by less than 10% in striatal membrane preparations in the absence of guanine nucleotide. The dose-response relationship for EtOH stimulation of cortical AC activity in the presence of guanylylimidodiphosphate (Gpp(NH)p) was biphasic, whereas, in the striatum, a linear dose-response relationship for EtOH was found for stimulation of AC in the presence of Gpp(NH)p. Activation of AC by Gpp(NH)p occurred as an apparent pseudo-first order process. EtOH increased the pseudo-first order rate constant for activation of AC by Gpp(NH)p in the cortex, but not in the striatum. Following 10 min preincubation with Gpp(NH)p, catecholamines and Gpp(NH)p were not able to stimulate further the AC activities in either tissue. Nevertheless, EtOH increased AC activity in both cortex and striatum following the preincubation with Gpp(NH)p. These data suggest that one effect of EtOH in striatal tissue is to promote the interaction of an activated guanine nucleotide-binding regulatory protein (G-protein) with the catalytic unit of AC. In cortical tissue, the effects of EtOH may be attributable to direct actions on the catalytic activity of the enzyme, effects on the rate of activation of the G-protein, and an altered interaction of G-protein with the catalytic unit.

Conventional vs. triple rubber band ligation for hemorrhoids. A prospective, randomized trial

Two hundred five patients with symptomatic first- and second-degree hemorrhoids were randomized to receive either conventional rubber band ligation or triple rubber band ligation. In conventional rubber band ligation, the hemorrhoids were ligated at one primary site per session at intervals of four weeks until symptoms were relieved or when all three hemorrhoids were ligated. In triple rubber band ligation, all three primary hemorrhoids were ligated in a single session. After completion of treatment, the patients were examined every three months, or earlier if symptoms recurred. Both methods were effective in the treatment of early hemorrhoids and the incidence of postligation pain and complications was similar. The advantages of having the treatment completed at the initial visit in triple rubber band ligation are obvious. Furthermore, less treatment sessions were required for triple rubber band ligation to control symptoms than for conventional rubber band ligation. Triple rubber band ligation is more cost-effective and therefore is recommended.

Radio-frequency analysis of the effect of haloperidol and cyclo (leucyl-glycyl) on apomorphine-induced stereotypy

Our previous studies indicated that the peptide cyclo(leucyl-glycyl) (cLG) prevents the development of supersensitivity to dopamine in several animal models at both biochemical and behavioral levels. We therefore tested cLG in a paradigm more commonly used to model tardive dyskinesia, namely chronic haloperidol administration to rats. We found that cLG administered subcutaneously at a dose of 8 mg/kg, blocked about 50% of the supersensitizing effects of of haloperidol on apomorphine-induced stereotypic behaviors. Further, we used a novel method, radio-frequency analysis, that quantifies sniffing and other stereotypic movements. Unlike methods that rely on visual observation of stereotypy and utilize an ordinal scale, these measurements are rated by an automatic motility monitor and utilize a ratio scale. Unlike other automated motility monitors, this device can distinguish between various forms of stereotypic behaviors. Since parametric statistics can be used, there is a significant improvement in the efficiency of the task of rating and comparing stereotypy scores.

Anisotropic tensile viscoelastic properties of vascular graft materials tested at low strain rates

Mechanical matching of vascular grafts and host vessels has been suggested to be important in determining graft patency rates. In this context, we have examined the anisotropic viscoelastic properties of natural vessels and some synthetic replacements using low strain rate tensile testing of circumferential and longitudinal strips. The canine iliac artery and iliac vein were compared with 6 mm diameter woven and knitted Dacron grafts, expanded polytetrafluoroethylene (PTFE) grafts, and helically constructed prototype polyurethane grafts at wrap angles of 45, 60 and 75 degrees. A thick-walled pressure vessel analysis was used to approximate physiological stress levels, and SEM was used to correlate anisotropic properties with graft wall structure.

Mild footshock stress dissociates substance P from substance K and dynorphin from Met- and Leu-enkephalin

Mild footshock stress selectively activates ventral tegmental area dopamine neurons innervating the prefrontal cortex. The same stressor rapidly dissociates ventral tegmental substance P from its preprotachykinin-derived co-transmitter substance K, and preproenkephalin B-derived dynorphin B from preproenkephalin A-derived Met-enkephalin-Arg-Gly-Leu and Leu-enkephalin. Mild footshock stress may provide a paradigm for studying both peptidergic modulation of brain dopaminergic neurons and the dynamic regulation of tachykinin and opioid peptide transcription, processing and utilization.

In vivo down-regulation of rat striatal opioid receptors by chronic enkephalin

Administration of methionine enkephalin (ICV) to rats for 5 days resulted in the development of physical dependence as exemplified by a hypothermic response which peaked 2-8 hours after initiation of withdrawal. Twenty-four hours post-withdrawal, opioid receptor binding was determined in the striatum using a selective delta receptor ligand. These studies revealed a decreased in the number of receptors. Bmax decreased from 193 +/- 20.4 fmoles/mg protein in controls to 136 +/- 9.7 fmoles/mg protein in enkephalin treated rats. This difference is significant at p less than 0.001. Existing evidence suggests that this decrease in binding is predominantly due to a decrease in delta receptors. Hence, the present findings indicate that delta receptor down-regulation in vivo may be an important mechanism in the adaptive response to chronic exposure to an endogenous opioid peptide.

Observations on the effect of movement on bone ingrowth into porous-surfaced implants

Although porous-surfaced orthopedic implants have been designed for fixation by bone ingrowth, there is clinical evidence that this does not always occur. Initial implant movement relative to host bone can result in attachment by a nonmineralized fibrous connective tissue layer. The ranges of movement that result in either bone or fibrous connective tissue fixation are observed in dogs in two independent studies. Experimentally, bone ingrowth can occur in the presence of some movement, albeit very small (up to 28 mu), while excess movement (150 mu or more) can result in attachment by mature connective tissue ingrowth.

Dopamine antagonist haloperidol decreases substance P, substance K, and preprotachykinin mRNAs in rat striatonigral neurons

Rat genomic clones were used to quantitate preprotachykinin mRNAs in the rat basal ganglia, while the tachykinin peptide products substance P and substance K were measured by radioimmunoassay. Administration of the dopamine antagonist (antipsychotic) drug haloperidol significantly decreased substance P, substance K, and both alpha (substance P encoding) and beta (substance P/substance K encoding) preprotachykinin mRNAs, suggesting a drug-induced decrease in striatonigral tachykinin biosynthesis. The time course for decreased preprotachykinin mRNAs and tachykinins apparently parallels the period of maximum risk for the development of certain antipsychotic drug-induced extrapyramidal side effects seen clinically. Tachykinin interaction with dopamine neurons may play an important role in the modulation of basal ganglia function.

Colonoscopy in the diagnosis of abdominal tuberculosis in children

Childhood abdominal tuberculosis has protean manifestations and remains a difficult diagnosis problem, often requiring surgery for pathological confirmation. Colonoscopy, however, can now be performed with safety in children and appears to offer a new and better alternative to surgery. An earlier experience confirmed its value in the management of ileocaecal tuberculosis as it provided histological proof and bacteriological information to guide chemotherapy, avoiding the need for anaesthesia and laparotomy. However, colonoscopy hasn't been helpful in the diagnosis of the 'exudative' type of abdominal tuberculosis.

The localization and characterization of substance P and substance K in striatonigral neurons

Specific substance P and substance K radioimmunoassays coupled to high-performance liquid chromatography were used to characterize striatal and nigral tachykinin immunoreactivity. Using these assays, authentic substance P and substance K accounted for nearly all substance P and substance K immunoreactivity, respectively. A series of coronal knife cuts of the striatum caused parallel depletions in nigral substance P and substance K, consistent with the possible colocalization of these tachykinins in striatonigral neurons.

Whole-gut irrigation in infants and young children

In the search for a superior alternative to conventional bowel preparation which often gives unsatisfactory results in children, we have introduced whole-gut irrigation for pediatric use. After a pilot study on 15 children during which adjustments on the technique were made, we settled on an intensive regimen with some notable modifications from conventional adult practice: the use of warm Hartmann's solution, a relatively large fluid load (mean volume 5.3 l/kg body weight, range 3.0 - 12.0 l/kg) and a rapid infusion rate (1.5 ml/kg/min). We then evaluated its safety, effectiveness, and acceptability prospectively on 45 patients undergoing colonoscopy or colorectal surgery, age ranging from 4 months to 11 years, with a mean of 3.9 years. Subjective complaints were mild and included nausea/vomiting, 12 cases (26.7 percent); abdominal colic, two (4.4 percent); and distending discomfort, three (6.7 percent). There was a mean weight gain of 4.0 percent but no gross electrolyte disturbances. Results of bowel preparation were satisfactory in 33 (73.3 percent), adequate in ten (22.2 percent) and poor in two (4.4 percent). Compared with our previous method, in which inadequate preparation occurred in 4/20 patients, (20 percent) by conventional measures, whole-gut irrigation represents a statistically significant improvement (P less than 0.05). In addition, whole-gut irrigation shortened hospital stay and obviated the traditional need of two to three days' dietary restrictions.

The use of the disposable intraluminal stapler in the definitive management of Hirschsprung's disease

Preliminary experience with seven infants with Hirschsprung's disease has demonstrated the safety and reliability of performing a very low colorectal anastomosis using a disposable intraluminal stapler. A 21-mm diameter stapler allows this procedure to be performed on patients with a mean body weight of approximately 10 kg.

The purification of alphavirus virions and subviral particles using ultrafiltration and gel exclusion chromatography

Conventional methods of virus purification using ultracentrifugation frequently result in distorted particles with low levels of biological activity, and are thus unsuitable for preparing samples for high-resolution techniques such as neutron scattering, X-ray scattering in solution, and X-ray crystallography. Moreover, in the event of an instrument failure, ultracentrifugation can also pose a significant hazard when preparing pathogenic viruses or subunits derived from them. By employing exclusively ultrafiltration and gel exclusion chromatography, a method has been developed to prepare highly purified, intact alphavirus particles retaining high levels of biological activity. These procedures have also been adapted to prepare aggregates of viral envelope protein with a defined immunogenic content.

Mechanical properties of human pericardium. Differences in viscoelastic response when compared with canine pericardium

Whereas most experiments on the mechanical function of the pericardium have been performed on dogs, very little is known about the applicability of those data to humans. To examine the tensile viscoelastic properties of fresh human pericardium, we have used the methods from our previous study of canine pericardium. Although the mechanical responses of canine and human pericardium were qualitatively similar, human pericardium displayed a significantly greater viscous character. Human pericardium was 7.3 times thicker than canine pericardium, but was more extensible in stress-strain tests, with lower stiffness at a given strain. The static (elastic) stiffness of human pericardium seems identical to that of canine pericardium; lower stiffness per unit thickness of the human tissue at predicted physiological stresses was almost exactly compensated by the greater wall thickness. This effect was also seen in data on fracture strength and stiffness. However, human pericardium displayed greater viscous responses than the canine tissue. This was seen in doubled cyclic hysteresis losses, and greater stress relaxation and creep. Our results suggest that experiments on the viscoelastic properties of canine pericardium may not be directly applicable to humans, especially where dynamic mechanical properties are most important: i.e., in studies of ventricular function and the time-course of pericardial effusions.

Antigenic relationships between an isolate of the Western Subtype of tick-borne encephalitis virus and an inactivated vaccine derived from it

High mutation rates resulting from the error prone replicases of RNA viruses could lead to antigenic alterations in viral products and pose significant problems during the manufacture of vaccines against RNA viruses. The production of a vaccine against tick-borne encephalitis virus has been monitored using both polyclonal sera and a library of monoclonal antibodies. Only a few antigenic changes were detected during the alteration of host cell from mouse brain to avian fibroblasts and upon subsequent expansion of the virus population during several rounds of replication. In addition, when the formalin inactivation process was monitored for antigenic change, virtually none was detected.

Surgical management of choledochal cysts: a review of 60 cases

Sixty cases of choledochal cysts in children are reviewed. The series comprises 55 cases of Alonso-Lej. Type 1 cysts, two cases whose cysts were infraduodenal and retropancreatic in position, and three cases of choledochal cysts with both proximal and distal atresia of bile ducts. The following five types of operative procedures were employed for the 58 cases: (1) Choledochocystoduodenostomy in 12; (2) Partial excision, choledochorraphy and choledocho-duodenostomy in six; (3) Cyst excision, portal dissection and portojejunostomy in three; (4) Choledochocystojejunostomy Roux-en-Y in 20; and (5) Cyst excision with hepaticojejunostomy Roux-en-Y in 17 cases. Two patients did not receive definitive surgical treatment. Early complications included six cases of leakage, of which one died; and four cases of cholangitis and septicemia, resulting in fatality in all. The overall operative mortality was 5/58 (8.6%). This review, though retrospective in nature, further supports the more recent trend that radical cyst excision with hepaticojejunostomy is the treatment of choice. This procedure carried no mortality and low morbidity. All 17 patients treated in this manner are well and free from jaundice and recurrent cholangitis. Cyst excision eliminates the reservoir for bile stasis, biliary obstruction, cholangitis, and biliary cirrhosis. It also removes the possibility of malignant change in the cyst and spontaneous rupture.