Pinhole collimator scintigraphy in differential diagnosis of metastasis, fracture, and infections of the spine

The informational gains obtained by the use of pinhole collimator scintigraphy (PCS) have been well documented. The present study has been undertaken to prospectively investigate its efficacy in diagnosing several commonly occurring spinal diseases. Patient material consisted of metastatic cancer (39 vertebrae), compression fractures (33 vertebrae), tuberculous spondylitis (17 vertebrae), and pyogenic spondylitis (six vertebrae). PCS findings were characterized in terms of localization, appearance, and homogeneity of abnormal radionuclide accumulation. Thus, metastatic cancer manifested as diffusely or focally homogeneous accumulation within the vertebral body or as a typical short-segmental accumulation along the end-plate, whereas compression fracture manifested as characteristic board-like accumulation along the entire length of end-plates. Tuberculous spondylitis, on the other hand, revealed homogeneous accumulation throughout the vertebral body, and pyogenic spondylitis revealed accumulation at the end-zone of opposing vertebral bodies giving sandwich-like appearance. The disk space at the affected level was not narrowed in the former two diseases but it was narrowed in the latter two. It was concluded that PCS may be useful in differentiating metastatic cancer, compression fracture, tuberculous spondylitis, and pyogenic spondylitis.     

Calculation of Hydrolytic Rate Constants of Poly(ortho ester)s from Molecular Weights Determined by Gel Permeation Chromatography

Purpose. To obtained rate constants from weight-averaged (M_w) or z-averaged (M_z) molecular weights for polymers of Schule-Flory distribution and undergoing random scission. These constants were compared with those obtained by parallel ¹HNMR studies. Methods. The hydrolysis of two poly(ortho ester)s were followed by ¹HNMR and gel permeation chromatography (GPC). Results. Equations to convert number-averaged (M_n), M_w and M_z into fraction of backbone remaining (f_c) were derived. First-order hydrolytic rate constants of two poly(ortho ester)s; DETOSU-HD and DETOSU-CDM were calculated using these relationships. The rate constants calculated from ¹HNMR, M_z and M_w were 0.215, 0.218 and 0.182 hr^–1, respectively, for DETOSU-CDM and 0.152, 0.086 and 0.038 hr^–l for DETOSU-HD. The large discrepancy in the rates determined by ¹HNMR and GPC in the latter case was attributed to that the detector response (refractive index) of the monomers was lower than that of the high molecular weight polymer. The difference is small in the case of DETOSU-CDM, and the rates calculated from GPC data were comparable or nearly identical to that obtained from ¹HNMR data. Conclusions. Although GPC can yield rapid and valuable kinetic data for the degradation of biodegradable polymers, the system, however, must be carefully calibrated to account for the variations in Mark-Houwink coefficients and in the response of the mass detector between the high and low MW polymers.     

Liver transplantation for erythropoietic protoporphyria liver disease.

In erythropoietic protoporphyria (EPP), there is excessive production of protoporphyrin, primarily in the bone marrow, resulting in increased biliary excretion of this heme precursor. Some patients will develop progressive liver disease that may ultimately require liver transplantation. However, excessive production of protoporphyrin by the bone marrow continues after transplantation, which may cause recurrent disease in the allograft. This study was performed to define post-transplant survival, the risk of recurrent disease, and specific management issues in patients transplanted for EPP liver disease. The patients studied consisted of twelve males and eight females, with an average age of 31 (range, 13-56) years at the time of transplantation. The estimated maximum MELD score prior to transplant was 21 (range, 15-29). Unique complications in the perioperative period were light induced tissue damage in four patients and neuropathy in six, requiring prolonged mechanical ventilation in four. Patient and graft survival rates were 85% at 1 year, 69% at 5 years, and 47% at 10 years. Recurrent EPP liver disease occurred in 11 of 17 patients (65%) who survived more than 2 months. Three patients were retransplanted at 1.8, 12.6, and 14.5 years after the initial transplant for recurrent EPP liver disease. In conclusion, the 5-year patient survival rate in patients transplanted for EPP liver disease is good, but the recurrence of EPP liver disease appears to diminish long term graft and patient survival.     

Preservation of the spleen using human fibrin seal

Because of the spleen's role in host defence and the recognition of overwhelming post-splenectomy sepsis, the current aim of treatment for splenic injuries is to preserve the spleen. A number of hemostatic agents have been used in an effort to control bleeding but have not proved satisfactory. The authors report the results of an experiment using a two-component fibrin seal on injured rabbit spleens. In female rabbits a longitudinal laceration of the entire spleen was made. After 2 1/2 minutes of continuous hemorrhaging, the spleens were either not treated (5 rabbits) or treated by splenectomy suture repair or fibrin-seal repair. Hemoglobin values were measured preoperatively and 3 days postoperatively. The greatest number of deaths within 14 days occurred in the untreated group. There was no difference in death rate between the treated groups; similarly, there was no difference in blood loss or fall in hemoglobin values. Fewer adhesions formed in the fibrin-seal group than in the others (p less than 0.02). Histopathological examination revealed a greater fibrinoblastic response in the spleens treated with fibrin seal than in the other groups. The authors believe that fibrin seal is an effective and safe hemostatic agent applicable to splenic parenchymal injuries, and that it promotes wound healing and suppresses adhesion formation.     

Recombinant tissue-plasminogen activator (rt-PA) in acute myocardial infarction in the Chinese in Hong Kong.

Eighty-nine consecutive Chinese patients (69 males, 20 females) with acute myocardial infarction treated by 100 mg recombinant tissue-plasminogen activator (rt-PA) (7 intracoronarily, 82 intravenously) at 3.7 +/- 1.0 hours after onset, and intravenous heparin or dipyridamole therapy started at 3 hours, were studied prospectively. Their mean age was 59.6 +/- 10.6 years. Forty-six patients (51.7%) had anterior and 39 patients (43.8%) had inferior infarcts. Clinical evidence of reperfusion was seen in 63 patients (72.8%), while new complications included hypotension (5.6%), heart failure (6.7%), cardiac arrhythmias (76.4%), hematoma around vascular access sites (23.6%), melena (2.2%) and cerebral infarction (2.2%). Maximal changes in coagulation profiles were seen at 3 hours, including a decrease in fibrinogen (by 64.2%), an increase in FDP by 11.7 times and D-dimers by 4.4 times. Nine patients (10.1%) had recurrence of angina and 6 patients (6.9%) died due to pump failure (5) and reinfarction (1). Angiogram at 14 days confirmed TIMI (2 or 3) patency of infarct related arteries in 62/81 (76.5%) patients, with a mean global ejection fraction of 52.5 +/- 12.4%. Nearly all survivors could maintain class I-II functional status after discharge. The safety and promises of rt-PA for acute myocardial infarction in the Chinese were confirmed.

     

Rat liver regeneration after partial hepatectomy: effects of insulin, glucagon and epidermal growth factor.

This study evaluated the role of insulin, glucagon and the epidermal growth factor (EGF) on liver regeneration after partial hepatectomy. Male Wistar rats, weighing approximately 200 g, were used. A partial hepatectomy, with resection of the medial and left lateral lobes (67.31%), was performed on the control group and seven hormone-treated groups: insulin, glucagon, EGF, insulin plus glucagon, insulin plus EGF, glucagon plus EGF, and a combination of the three hormones. The hormones were administered subcutaneously two days prior to the partial hepatectomy. The groups administered insulin were allowed to drink 20% glucose in water. Another group of rats received simulated operations, i.e., only a laparotomy was performed. The rats were killed at six, 24, 48 and 72 hours after the operation. Remnant liver weight, deoxyribonucleic acid (DNA) content, rate of DNA synthesis, mitotic index, blood glucose and serum insulin levels were measured. The results showed that: 1) the effects of single hormone administration on posthepatectomy liver regeneration were not obvious; 2) combined administration of insulin and glucagon increased the weight of the remnant liver, the DNA content, and the rate of DNA synthesis; 3) the combined administration of insulin, glucagon, and EGF increased the regeneration based on the remnant liver weight and mitotic index; and 4) there was no concordance between the change in blood glucose levels and the effect of hormones during liver regeneration.     

Conservative treatment of neonatal hydronephrosis.

From February 1990 to January 1991, 19 cases of hydronephrosis in children of less than one year of age were managed at Mackay Memorial Hospital. In the majority of these patients, there were evident causes such as ureteropelvic junction stenosis, ureterovesical reflux or a posterior urethral valve for which definite therapeutic measures were performed. However, some cases had no obvious origins and the hydronephrosis was speculated to be from nonobstructive or physiologic dilatation of the kidneys. The conventional tools, such as intravenous pyelogram or renal ultrasound, which comprise the mainstay of diagnosis, provide limited information on renal functional status. Recent introduction of the Tc-99m diethylene triamine penta-acetic acid (DTPA) diuretic renal scan has enabled us to distinguish between obstructive and nonobstructive hydronephrosis and helps us to determine whether or not surgery is necessary. In the past year, eight patients with hydronephrosis of less than one year of age were diagnosed as nonobstructive after a series of evaluations using renal ultrasound, voiding cystourethrography (VCUG) and Tc-99m DTPA diuretic renal scan. Follow-up studies by echography or DTPA renal scan revealed spontaneous resolution of the dilated collecting systems in these cases and confirms our belief that some hydronephrosis in neonates and infants may resolve spontaneously and may just be a manifestation of physiologic change during development. The value of the Tc-99m DTPA diuretic renal scan in the diagnosis of obstructive uropathy is discussed.