Neurophysiological field potential analysis by microcomputer

A system is described for digitizing, storing, displaying, analyzing, and creating hardcopy drawings of electrophysiological field potential data, based on the Apple II microprocessor. The system uses commercially available hardware and user oriented software written in BASIC.     

Localization of collagen in the rat lung: biochemical quantitation of types I and III collagen in small airways, vessels, and parenchyma

The marked insolubility of pulmonary collagen has limited its accurate biochemical quantitation in small samples of lung and other tissues. We have recently developed a microassay based on radioisotope dilution techniques that we have used for the accurate determination of types I and III collagen in extremely small tissue samples. By applying this method to carefully dissected small airways and vessels and samples of parenchymal tissue of rat lungs, we have localized and quantitated biochemically the type I and III structural collagens of the lung. Large pulmonary arteries are the units richest in these interstitial collagen types on the basis of dried tissue weight (50 micrograms/100 micrograms dried tissue). Amounts of both types I and III collagen are considerably lower in the alveolar domain than in vessels and airways of the rat lung. The proportion of tissue composed of these collagen types decreases centripetally in rat pulmonary arteries, but increases in the bronchial tree. The relative proportions of type I and type III remain constant in all the structures tested. The higher total amount of collagen in the nonalveolar domain has implications for biochemical studies based on whole lung samples.     

One- and two-level anterior cervical discectomy and fusion: the effect of plate fixation.

BACKGROUND CONTEXT: The success of arthrodesis for anterior cervical fusion depends on several factors, including the number of surgical levels. Internal fixation putatively improves the arthrodesis rate and outcome. PURPOSE: To provide medium-term follow-up data on the surgical success and patient outcome of one- and two-level anterior cervical discectomies and fusions and to determine the effect that plate fixation has on results. STUDY DESIGN: A prospective study of 40 patients who underwent modified Smith-Robinson anterior cervical discectomy and fusion at one or two operative levels. PATIENT SAMPLE: Forty patients. OUTCOME MEASURES: Odom criteria, Nurick grading system, radiographs. METHODS: Forty patients, with an average age of 44 years (range, 27 to 82), were followed for an average of 51 months (range, 24 to 85). All had an anterior discectomy, burring of the end plates and placement of an autogenous tricortical iliac crest graft at one (20 patients) or two levels (20 patients). Twenty-three were stabilized with the Cervical Spine Locking Plate (Synthes Spine, Paoli, PA), 4 single level, 19 two level. All patients had follow-up office visits with examinations and radiographs. Radiographic union, postoperative pain relief and neurologic recovery were evaluated.RESULTS: Successful arthrodesis of single-level procedures occurred in 11 of 16 unplated and 2 of 4 plated fusions. Primary bony union in the two-level group was achieved in 15 of 19 plated patients and did not occur in the single unplated procedure. Clinically, there were 12 excellent, 5 good, 3 satisfactory and 0 poor outcomes among the single-level procedures. Among the dual-level procedures, there were 10 excellent, 5 good, 3 satisfactory and 2 poor results. Nine of 16 who developed adjacent-level degeneration had pain. Five of the 9 also had nonunions. Of the 40, 3 had fibrous union at final follow-up, and 10 had revision surgery. CONCLUSIONS: The Cervical Spine Locking Plate improved the outcome of two-level procedures to that of uninstrumented one-level fusions. Adjacent-level degeneration is associated with persistent pain, especially if there is also a nonunion. Primary bony union is paralleled by a better clinical outcome.     

Localization of collagen in the rat lung: biochemical quantitation of types I and III collagen in small airways,vessels, and parenchyma

The marked insolubility of pulmonary collagen has limited its accurate biochemical quantitation in small samples of lung and other tissues. We have recently developed a microassay based on radioisotope dilution techniques that we have used for the accurate determination of types I and III collagen in extremely small tissue samples. By applying this method to carefully dissected small airways and vessels and samples of parenchymal tissue of rat lungs, we have localized and quantitated biochemically the type I and III structural collagens of the lung. Large pulmonary arteries are the units richest in these interstitial collagen types on the basis of dried tissue weight (50 μg/100 μg dried tissue). Amounts of both types I and III collagen are considerably lower in the alveolar domain than in vessels and airways of the rat lung. The proportion of tissue composed of these collagen types decreases centripetally in rat pulmonary arteries, but increases in the bronchial tree. The relative proportions of type I and type III remain constant in all the structures tested. The higher total amount of collagen in the nonalveolar domain has implications for biochemical studies based on whole lung samples.     

Glycosyl transferase activity in homogenates of adult Dirofilaria immitis

Homogenates of adult Dirofilaria immitis possess a microsomal enzyme system able to transfer mannose from GDP-mannose to endogenous lipid intermediate(s) and exogenous dolichol monophosphate. A divalent metal was required with Mn²⁺ being the most effective; other requirements for optimal activity included Triton X-100, EDTA and either ATP or NaF. The maximal rate of mannose transfer to the lipid acceptor by the filarial system, 1.6 pmol · min^?1 · mg^?1 protein, occurred at 37°C and pH 7.0, and this was inhibited 50% by 8 μM diumycin and not at all by 100 μM tunicamycin. D. immitis microsomes also were shown to promote the transfer of mannose to derivatives of α-lactalbumin, resulting in the synthesis of a mannose-labeled glycoprotein.     

Thymidine kinase activity and thymidine salvage in adult Brugia pahangi and Dirofilaria immitis

Cytosolic thymidine kinase (EC 2.7.1.75), the initial enzyme in the thymidine salvage pathway, was detected in crude homogenates of adult female Brugia pahangi and Dirofilaria immitis, with respective specific activities of 100 and 460 nmol/h/mg protein. Partially purified filarial thymidine kinases were found to have molecular weights of approximately 180 000, to be most active in the presence of Mg²⁺ and ATP, to have a sharp pH optimum (pH 7.0) and to be heat-labile in the absence of added thymidine. For both, the respective K_m values for thymidine and ATP were 60 μM and 1.6 mM, and 5-iodo-2′-deoxyuridine was as good a substrate as thymidine. A distinguishing property was the 3-fold higher sensitivity of the B. pahangi enzyme to feedback inhibition by thymidine 5′-triphosphate. Adult female B. pahangi took up and incorporated [methyl-³H] thymidine into DNA when they were exposed to this radiolabeled deoxynucleoside in vivo, but the thymidine salvage pathway in these worms was essentially nonfunctional in vitro.     

Thymidylate synthetase activity in normal and brugia pahangi-infected aedes aegypti.

Thymidylate synthetase (5,10-methylenetetrahydrofolate: dUMP C-methyltransferase; EC 2.1.2.45; TMPS) activity was detected in crude extracts of 4 to 5 day-old adult male and uninfected female Aedes aegypti. Mosquito TMPS was strongly inhibited by Mg²⁺ and Ca²⁺ (id₅₀ values of 0.25 and 0.12 μM, respectively) but not by other divalent cations. The K_m values for dUMP and 5, 10-methylene-tetrahydrofolate were 55 and 100 μM, respectively. It appeared that mosquito TMPS would not be subject to regulation by physiological concentrations of thymidine mono-, di- and triphosphates or di- and triphosphates of cytidine, uridine, adenosine or guanosine. When subjected to Sephadex G-200 gel filtration, TMPS activity occurred in three peaks, corresponding to molecular weights of 210,000, 310,000 and 450,000. Among a variety of compounds tested as inhibitors of the enzyme, FdUMP was the most potent, with an id₅₀ value of 0.5 nM; by contrast, FUdR was inactive at 1.0 mM. The polycyclic sulfonated anionic drug, suramin, was also a strong inhibitor of mosquito TMPS, with an id₅₀ value of 0.3 μM. Various 2,4-diaminoheterocyclic antifols, including methotrexate, either were inactive or were relatively weak inhibitors of this enzyme. The total activity of TMPS did not change in extracts of female mosquitoes prepared 7 and 12 days after they fed upon either normal or Brugia pahangi-infected jirds.     

Three- and four-level anterior cervical discectomy and fusion with plate fixation: a prospective study

STUDY DESIGN: A prospective study of 15 patients who underwent modified Smith-Robinson anterior cervical discectomy and fusion at three or four operative levels stabilized with an unicortical anterior plate. OBJECTIVES: To provide medium-term follow-up data on the surgical success and patient outcome of three- and four-level anterior cervical discectomies and fusions and to determine the effect that plate fixation has on the results. SUMMARY OF BACKGROUND DATA: The success of arthrodesis for anterior cervical fusion depends on several factors, including the number of surgical levels. The arthrodesis rate and outcome for patients having three- and four-level discectomy and fusion procedures is disappointing. Internal fixation putatively improves these parameters. METHODS: Fifteen patients (average age, 51 years; range, 35-77), were observed for an average of 42 months (range, 25-73) All had an anterior discectomy, burring of the endplates, placement of an autogenous tricortical iliac crest graft at three (12 patients) or four (3 patients) levels, and application of a Cervical Spine Locking Plate. All patients had follow-up office visits with examinations and radiographs. Radiographic union, postoperative pain relief, and neurologic recovery were evaluated. RESULTS: Solid arthrodesis was achieved at all levels in only 7 (47%) of the 15 patients after a single procedure. Of the 8 patients with pseudarthrosis, 3 had sufficient pain to necessitate revision surgery (with pain relief in two), 1 had pain without further surgery, and 4 no pain. Of the 7 with solid fusion, 3 had persistent pain, and 4 had none. Two in this group had a second procedure. All 4 patients with preoperative myelopathy improved, and 10 of the 11 with radiculopathy had resolution of arm symptoms. CONCLUSIONS: Three- and four-level modified Robinson cervical discectomy and fusion results in an unacceptably high rate of pseudarthrosis. The Cervical Spine Locking Plate alone does not appear to improve the arthrodesis rate.