SPINAL CORD TRANSECTION: A QUANTITATIVE ANALYSIS OF ELEMENTS OF THE CONNECTIVE TISSUE MATRIX FORMED WITHIN THE SITE OF LESION FOLLOWING ADMINISTRATION OF PIROMEN, CYTOXAN OR TRYPSIN

Spinal cord transection: a quantitative analysis of elements of the connective tissue matrix formed within the site of lesion following administration of piromen, cytoxan or trypsin
Long-Evans hooded rats were cordotomized at the T-5 level and given either (1) cyclophosphamide (cytoxan), an immunosuppressive, (2) piromen, a bacterial polysaccharide-nucleic acid complex, (3) topical and systemic trypsin, or (4) no further specific treatment. Because of past and present controversy surrounding the proposed ability of these agents to promote spinal cord regeneration, a systematic study, employing light and electron microscopy, and quantitative methods in a single animal model, was done in order to re-evaluate the effects of each treatment upon the connective tissue matrix which forms in the defect left by transection. After an initial inflammatory reaction during the first week after surgery, the lesion zone is characterized either by areas of dense collagenous connective tissue with occasional fibroblasts and macrophages, or a loose areolar tissue with numerous sheets and cords of mesodermal cellular elements but minimal collagen. By 45 days postoperatively (dpo), axons supported by Schwann cells invade and become entangled in the loose connective tissue matrix. With longer postoperative survival, cysts appear craniad and caudad to the lesion and erode much of the scar together with viable neural tissue. Giving cytoxan or piromen did not result in any qualitative alteration of the scar matrix as evidenced by electron microscopy. Quantitative analysis revealed a slight reduction in the fibrous connective tissue component of the scar at 45–90 dpo, but this was transient when longer postoperative periods were studied. Trypsin caused a significant reduction in the amount of fibrous connective tissue with a concomitant increase in loose connective tissue and the appearance of a few distinctive, compact bundles of unmyelinated axons lacking Schwann cells.     

Prior Calcium Channel Blockade and Short-Term Survival Following Acute Myocardial Infarction

There is concern over the safety of calcium channel blockers (CCBs) in acute coronary disease. We sought to determine if patients taking calcium channel blockers (CCBs) at the time of admission with acute myocardial infarction (AMI) had a higher case-fatality compared with those taking beta-blockers or neither medication. Clinical and drug treatment variables at the time of hospital admission predictive of survival at 28 days were examined in a community-based registry of patients aged under 65 years admitted to hospital for suspected AMI in Perth, Australia, between 1984 and 1993. Among 7766 patients, 1291 (16.6%) were taking a CCB and 1259 (16.2%) a betablocker alone at hospital admission. Patients taking CCBs had a worse clinical profile than those taking a beta-blocker alone or neither drug (control group), and a higher unadjusted 28-day mortality (17.6% versus 9.3% and 11.1% respectively, both P < 0.001). There was no significant heterogeneity with respect to mortality between nifedipine, diltiazem, or verapamil when used alone, or with a beta-blocker. After adjustment for factors predictive of death at 28 days, patients taking a CCB were found not to have an excess chance of death compared with the control group (odds ratio [OR] 1.06, 95% confidence interval [CI]; 0.87, 1.30), whereas those taking a beta-blocker alone had a lower odds of death (OR 0.75, 95% CI; 0.59, 0.94). These results indicate that established calcium channel blockade is not associated with an excess risk of death following AMI once other differences between patients are taken into account, but neither does it have the survival advantage seen with prior beta-blocker therapy.     

An evaluation of the prevalence of malnutrition in cancer patients attending the outpatient oncology clinic

Background: The aim of the study was to assess the nutritional status of cancer patients attending the medical oncology outpatient setting for the first time. Methods: One‐hundred and forty‐one patients (87 males, 54 females) were assessed by a dietitian, using the nutrition assessment tool, the Patient‐Generated Subjective Global Assessment (PG‐SGA). Tumor types included colorectal, head and neck, lung, pancreatic, gastric or esophageal cancer. No patient had previously received chemotherapy. Results: Forty‐eight (34%) patients were well nourished (PG‐SGA rating A), 79 (56%) patients were at risk of malnutrition (B), and 14 (10%) patients were malnourished (C). The median PG‐SGA score was 7. There were no significant differences in nutritional status between those > 65 years and those ≤ 65 years. The highest PG‐SGA scores (indicating a greater nutritional risk) were found in patients with gastric, pancreatic and oesophageal cancers. There were significant differences found between certain cancer groups using the PG‐SGA, however, these were not detected using other more commonly used criteria, such as the body mass index (BMI). Conclusion: This study confirms that the majority of new patients with cancer presenting to a medical oncologist are at risk of malnutrition or malnourished. It calls for better screening, and adequate nutrition intervention in patients who are about to be considered for systemic treatment.     

Radicular penetration of hydrogen peroxide during intra-coronal bleaching with various forms of sodium perborate

The development of external cervical root resorption following internal bleaching of discoloured pulpless teeth is associated with the use of hydrogen peroxide. The aim of the study was to determine radicular penetration of hydrogen peroxide following intracoronal bleaching with various forms of sodium perborate, 63 extracted human incisors were root filled and stained artificially. Standardized cementum defects were created on the mesial and distal aspects of the root directly below the cemento-enamel junction (CEJ). Using the walking bleach technique all teeth were bleached for a 6-day period, with replacement of the bleaching paste after days 1 and 3. Sodium perborate monohydrate (MH), trihydrate (TRH) or tetrahydrate (TH) was mixed with H₂O₂ or H₂O and subsequently placed intracoronatly 1 mm below the labial CEJ. The teeth were divided into six groups:

• I. MH + H₂O₂(30%)(n=12);
• II. TRH + H₂O₂(30%)(n=12);
• III. TH + H₂O₂(30%)(n=12);
• IV. TH + H₂O(n=12);
• V. TH + H₂O gel(n=12);
• VI. no bleaching paste (n= 3).

At baseline and at days 1, 3 and 6 the amount of H₂O₂ taken up from the surrounding medium of each root was indirectly recorded and calculated as p.p.m. Almost all teeth of the experimental groups showed leakage of hydrogen peroxide compared to those of the control group. The radicular penetration of hydrogen peroxide was significantly higher in teeth of groups I and III than in those of groups IV and V (P≤ 0.001). In conclusion, the amount of hydrogen peroxide leakage depends, among other factors, on the form of sodium perborate used. The risk of post-bleaching cervical root resorption may be diminished by using sodium perborate tetrahydrate in conjunction with H₂O.