Unconventional pedicle spinal instrumentation. The Bombay experience

STUDY DESIGN

A retrospective study of all patients who underwent spinal fusion between 1986 to 1989 with inexpensive, locally made unconventional pedicle spinal instrumentation systems was undertaken. Implants were made with passivated 316L stainless steel, and a single level of instrumentation cost +f430.

OBJECTIVES

To demonstrate that simple, cheap pedicle instrumentation systems are as effective as the conventionally available expensive systems, provided proper anterior column support is maintained.

METHODS

Ninety out of 102 patients were available for review. Average follow-up was 41 months (range, 22 to 60 months). Implant failures, screw placement, fusion rates, infection, neurologic deficit due to the implant, patient satisfaction, and the benefit of anterior column grafting with the unconventional pedicle spinal instrumentation systems in the long term were evaluated.

RESULTS

Forty-four out of 467 screws failed (9%) in 16 patients, seven of whom were symptomatic. There were no plate failures. On comparing burst fractures with (n = 12) and without (n = 10) anterior column grafting, the latter group had a significant increase in implant failures, loss of sagittal alignment, and the time required to fusion. Overall, fusion occurred within 6.5 months.

CONCLUSIONS

Anterior column reconstruction in anterior column deficient spines will re-create the normal biomechanics and significantly reduce the incidence of implant failures and loss of sagittal alignment with these systems. Pedicle screw failure in itself is not necessarily associated with a bad result. These inexpensive, locally made unconventional systems, with the proper understanding of biomechanics and creation of appropriate load-sharing constructs, are as good as the conventional systems available today.

p-Aminobenzene sulphonyl morpholine, compound 82/208 a new anticonvulsant agent

p-Aminobenzene sulphonyl morpholine, compound 82/208, was evaluated for acute toxicity and anticonvulsant action in mice against tonic seizures induced by supramaximal electroshock and pentylene tetrazole and strychnine induced seizures and for its effect on blood pressure and respiration in cat. Diphenyl hydantoin (DPH) was used as reference standard. Compound 82/208 exhibited anticonvulsant activity against electroshock induced seizures and PTZ induced tonic seizures in mice. The compound had several distinct advantages over DPH in experimental evaluation in mice.

Role of nitric oxide in esophageal peristalsis

In vitro studies have suggested that NO may be a nonadrenergic, noncholinergic inhibitory mediator in the esophageal body. We examined the role of NO in physiological peristalsis in anesthetized opossums by assessing the effect of the NO synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) on esophageal contractions induced by swallows, prolonged vagal efferent nerve stimulation, and midesophageal balloon distension. A perfused manometry system measured intraluminal pressures 1 and 5 cm orad to the lower esophagus, and suction electrodes monitored membrane potential changes at the same locations. NO synthase inhibition 1) decreased swallow-induced contraction amplitude in the distal esophagus and, when combined with atropine, abolished these contractions; 2) diminished swallow-induced contraction latencies, predominantly in the distal esophagus, thereby decreasing the latency gradient and increasing the peristaltic velocity; 3) abolished vagal-stimulation-induced, end-of-stimulus "B" contractions and either unmasked or increased the amplitude of intrastimulus "A" contractions; 4) abolished the contractions occurring at the end of balloon distension; and 5) inhibited the membrane hyperpolarization and the subsequent nonadrenergic, noncholinergic depolarization induced by all three stimuli. These data support the hypothesis that NO is a mediator of nonadrenergic, noncholinergic neurotransmission in the opossum esophagus. Furthermore, the data suggest that esophageal peristalsis is mediated by a "blended" activation of cholinergic and nonadrenergic, noncholinergic (via NO) neurons.

Ankle fractures in the elderly: MUA versus ORIF

A series of 80 patients over the age of 60 years with ankle fractures were reviewed retrospectively. 'Pilon' and talar fractures were excluded; 41 were treated conservatively (MUA) and 39 by operation (ORIF). The mean follow-up was 28 months (range 18-38 months) in the ORIF group and 25.5 months (range 12-40 months) in the MUA group. A statistically significant proportion of patients were satisfied with regard to pain, swelling, stiffness, instability and ranges of movement after ORIF. Anatomical congruity of the ankle mortice was better maintained following ORIF. Poor subjective and objective end results correlated with malalignment of the ankle mortice on the final radiograph at follow-up.

Pharmacological characterization of lower esophageal sphincter relaxation induced by swallowing, vagal efferent nerve stimulation, and esophageal distention

To characterize the neural pathways involved in lower esophageal sphincter relaxation, intraluminal pressures from the lower esophageal sphincter of the opossum were monitored during swallowing, vagal efferent nerve stimulation, and intraluminal balloon distention in the presence and absence of pharmacologic antagonism of putative neurotransmitters. The combination of atropine, hexamethonium, and 5-methoxydimethyltryptamine, which is known to block ganglionic transmission in the vagal inhibitory pathway to the lower esophageal sphincter, significantly antagonized LES relaxation induced by both swallowing and vagal stimulation, but did not affect the LES relaxation induced by balloon distention. Administration of the nitric oxide synthase inhibitor Nωnitro-L-arginine methyl ester, on the other hand, markedly inhibited LES relaxation induced by vagal stimulation, swallowing, and balloon distention, and this effect was reversed by administration of the nitric oxide synthase substrate L-arginine. These studies indicate that the distension-induced intramural pathway mediating LES relaxation does not involve ganglionic transmission similar to that of the vagal inhibitory pathway to the LES. However, the LES relaxation induced by all forms of stimuli appears to depend on nitric oxide as a final mediator.Key words: ganglionic transmission, muscarinic, nicotinic, serotonergic, nitric oxide.

Susceptibility of glucose-6-phosphate dehydrogenase deficient red cells to primaquine, primaquine enantiomers, and its two putative metabolites. II. Effect on red blood cell membrane, lipid peroxidation, MC-540 staining, and scanning electron microscopic studies

The effects of primaquine (PQ), its enantiomers [(+)PQ,(-)PQ] and hydroxy metabolites [5-hydroxyprimaquine (5HPQ) and 6-desmethyl-5-hydroxyprimaquine (6D5HPQ)] on cell membranes of glucose-6-phosphate dehydrogenase (G-6-PD) deficient red cells were studied in vitro. There was no significant effect of PQ on the malonyldialdehyde (MDA) content of normal and heterozygous red cells, but it caused a significant increase in MDA in G-6-PD deficient red cells (P less than 0.05). There was no noticeable difference between the effects of the two enantiomers on this variable (P greater than 0.05). Compared to PQ, the hydroxy metabolites produced a significantly greater increase in MDA in all the groups studied (P less than 0.001). Of the two hydroxy metabolites, 6D5HPQ was more toxic than 5HPQ. Staining with MC540 showed that exposure to PQ, its enantiomers and two putative metabolites produced significant fluorescence, indicating that the drug produces marked alterations in membrane fluidity. Although the fluorescence was seen both in normal and heterozygous cells, the effect was marked in hemizygous deficient red cells (P less than 0.001). Scanning electron microscopic (SEM) studies revealed that PQ enantiomers had a stomatocytic effect on red cells of normal, heterozygous and hemizygous G-6-PD deficient red cells, whereas the putative metabolites had an echinocytic effect. The effects were most pronounced in G-6-PD deficient red cells.

Synthesis and pharmacological studies of some (1,4)-naphthoquinono[3,2-c]-1H-pyrazoles, 2-substituted amino-1,4-naphthoquinones, and related compounds

Series of (1,4)-Naphthoquinono(3,2-c)-1H-pyrazoles and 2-substituted amino-1,4-naphthoquinones have been synthesised and studied for their possible anticancer activity (animal tumours, Walker 256 carcinosarcoma), Influenza RNA transcriptase activity, antibiotic activity (C. neoformans, T. mentagraphytes, M. canis, A. niger, and C. albicans).

Anti-stress activity in a muramyl-dipeptide

N-Acetylmuramyl-L-alanyl-D-isoglutamine and some of its derivatives have been examined for anti-stress activity. Amongst these, N-palmitoylmuramyl-L-alanyl-D-isoglutamine is shown to considerably enhance the capacity of animals to endure various types of stress. This indicates that besides acting as immunomodulators and sleep regulators, muramyl dipeptides may also act as anti-stress agents.