Chemical modification of implantable biologic tissue for anti-calcification

Biologic porcine tissue was modified by coupling sulfonated polyethyl-eneoxide (PEO-SO3) and the effect of modification on calcification was evaluated in vitro and in vivo. The modification process involves grafting PEO-SO3 to porcine valve leaflet either by carbodiimide (EDC) activation or by direct coupling using glutaraldehyde. Thermal property, measured by differential scanning calorimetry, showed that the shrinkage temperature of modified tissue increased compared with control tissue and fresh tissue, suggesting increased thermal stability. Resistance to collagenase digestion revealed that modified tissues have greater resistance to enzyme digestion than do control tissues. In vitro calcification showed that modified tissues have less calcium deposition than do control tissues. In vivo calcification, using a rat subcutaneous implantation model, also showed less calcification of modified tissue than that of control. The resistance of modified tissue to collagenase, higher shrinkage temperature, and reduced calcification, when compared with control tissue, attest to the usefulness of this chemical modification for implantable biologic tissue.

Morphometric study of the pedicles of thoracic and lumbar vertebrae in Koreans

STUDY DESIGN

The shape and size of the pedicles of the human spine differs within different races. The authors studied the diameters and angles of the spine pedicle from the T1 to L5 levels in Koreans. The following measurements were made 1) transverse diameter, 2) superoinferior diameter, 3) anteroposterior pedicle angle, 4) horizontal pedicle angle, and 5) pedicle axis angle.

OBJECTIVES

This study obtained indices of pedicle morphology in Koreans to use in transpedicular screw fixation and to explain the difference between other races and Koreans.

SUMMARY OF BACKGROUND DATA

Internal fixators for vertebrae fixation have been developed. Knowledge of pedicle morphology is essential for pedicle screw use. The use of pedicle screws in Asians is questionable. Few reports exist regarding pedicle morphology, and in those few reports, the pedicle isthmus diameter, pedicle angles, and the depth to the anterior cortex are emphasized.

METHODS

The following measurements of the diameter and length of the human cadaver pedicle were done with vernier and dial calipers: 1) transverse diameter of pedicles, 2) superoinferior diameter of pedicles, 3) anteroposterior pedicle angle, and 4) horizontal pedicle and pedicle axis angles.

RESULTS

The widest transverse diameter of the pedicle was seen at the L5 level and the narrowest was at the T4 level. The widest superoinferior diameter of the pedicle was seen at the T12 level, the narrowest was at the T1 level. In the transverse plane, the angles of the pedicles of T11 and T12 were faced laterally. The anteroposterior angle increased rapidly at the T4 level, with the T1 level having the greatest. In the sagittal plane, the horizontal angle of the lumbar vertebra was almost parallel to the horizontal plane. The pedicle axis was longest at the L3 level and shortest at the T1 level. In all areas, the transverse diameter of the pedicle in males was wider than the that in the female.

CONCLUSIONS

The results suggest that using 6-mm screws can violate the cortex of the pedicles in a significant number of levels of the upper lumbar spine. Using a screw longer than 40 mm is dangerous in the lower thoracic spine of a Korean. A statistical difference exists between the transverse diameter of the pedicles of Westerners and Koreans.

Proteolytic activity of human cytomegalovirus UL80 protease cleavage site mutants

The human cytomegalovirus UL80 open reading frame encodes protease and assembly protein from its N- and C-terminal regions, respectively. We reported previously that a 30-kDa protease is derived by autoproteolytic processing of a polyprotein which is the translation product of the entire UL80 open reading frame (E. Z. Baum, G. A. Bebernitz, J. D. Hulmes, V. P. Muzithras, T. R. Jones, and Y. Gluzman, J. Virol. 67:497-506, 1993). Three autoproteolytic cleavage sites within the UL80 polyprotein were characterized; site 143 is within the protease domain and inactivates the protease. In this article, we report (i) expression analyses of UL80 in infected cells, including the processing kinetics of the UL80 polyprotein; (ii) the existence of an additional cleavage site (site 209) within the protease domain of the UL80 polyprotein; and (iii) the effect of mutagenesis at each of the cleavage sites upon proteolytic activity and steady-state levels of the UL80 processing products. During the course of infection, UL80 polyprotein processing begins at cleavage site 643 and follows at sites 256 and 143. Cleavage at site 643 and/or 256 within the polyprotein is not a prerequisite for efficient protease activity, since all three proteases (85-, 80-, and 30-kDa proteins) were equally active in cleaving the assembly protein precursor to its mature form. Inhibition of cleavage at site 143 resulted in a three- to sixfold increase in the steady-state level of the 30-kDa protease, supporting the hypothesis that cleavage at this site may represent a mechanism by which cytomegalovirus regulates the level of active protease.

Mechanisms of hyperkalemia associated with hyporeninemic hypoaldosteronism in streptozotocin-induced diabetic rats

This study was aimed at investigating the mechanisms of clinically important overt hyperkalemia in diabetes mellitus with underlying hyporeninemic hypoaldosteronism known as a classic model of the syndrome of hyporeninemic hypoaldosteronism (SHH). Rats (Sprague-Dawley, male) were streptozotocin-treated (60 mg/kg, ip) and used after 60 days. Rats with plasma glucose levels higher than 300 mg/dL (mean +/- SEM, 423 +/- 20 mg/dL, n = 8) were selected as the diabetic group. Age-matched normal rats served as control (mean plasma glucose, 88 +/- 2, mg/dL, n = 8). Serum potassium concentrations and osmolalities as well as serum creatinine levels were significantly higher in the diabetic than in the control group (5.07 +/- 0.09 vs. 4.68 +/- 0.11 mEq/L; 330 +/- 14 vs 290 +/- 3 mOsm/L; 0.40 +/- 0.03 vs 0.31 +/- 0.02 mg/dL, p < 0.05). Plasma renin activity (PRA) in the diabetic group was significantly lower than that in the control group (6.0 +/- 1.0 vs 12.1 +/- 1.1 ng Al/ml/h, p < 0.001). Plasma aldosterone concentration (PAC) was also significantly lower in the former than in the latter (368 +/- 30 vs 761 +/- 57 pg/ml, p < 0.001). Renomegaly, abnormal distal tubular cells with few organelles, and increased lipid droplets with pyknotic nucleus in zona glomerulosa of the adrenal glands were noted in the diabetic group. In conclusion, multifactorial causes including insulinopenia, hyperosmolality, elevated serum creatinine level and hypoaldosteronism with possible contribution of altered distal tubular response to aldosterone may have interacted to develop hyperkalemia in these diabetic rats.

Surgical treatment of stage III lung cancer after chemotherapy and radiotherapy

We have experienced eight patients with advanced bronchogenic carcinomas who underwent resectional surgery after receiving preoperative adjuvant chemotherapy and radiotherapy during the period March, 1990, to February, 1992. Four patients were in stage IIIA and four in stage IIIB, of which six had epidermoid carcinomas and two small cell carcinomas. All patients were male with ages ranging from 48 to 73 (mean 56.7) years. The induction chemotherapy for six patients consisted of cisplatin and VP-16 (Etoposide) only, and two patients were given fluorouracil/cyclophosphamide and cyclophosphamide/adriamycin/cisplatin in addition to cisplatin/VP-16, respectively. All patients also received four to six weeks of radiotherapy following chemotherapy and were re-evaluated for the possibility of surgery after four weeks of observation. All patients underwent pneumonectomies. Postoperative histological staging revealed complete responses in two patients, partial responses in three and no response in three. Patients were followed-up for seven to 33 (mean 21.5) months after the diagnosis of lung cancer. Six patients died 1, 2, 3, 10, 14 and 26 months postoperatively and two patients are alive, revealing no evidence of tumor recurrence 24 months postoperatively. Induction therapy may induce a better resectability by the conversion of the lung cancer to a lower clinical stage by the time of surgery.

Morphological study of surgically induced open neural tube defects in chick embryos--postoperative 24 hours

For the experimental study of neural tube defect (NTD), a surgical model has advantages over other models in a few aspects. It causes less functional derangement of cells and the NTDs can be made selectively by surgery. The authors planned to use the surgical model for the experimental study of NTD. As the first step for the studies, the chronological changes of morphology during the early postoperative period were investigated using postincubation 3-day chick embryos. The objectives of this study are (1) the morphological evaluation of the surgical model as a method for studies of open NTD, and (2) the observation of morphological changes for the first 24 hours after surgery which include 'overgrowth' appearance and the continuity between the surface ectoderm and the neuroectoderm. The morphological changes were observed by light microscope and scanning electron microscope. Immediately after surgery, typical open NTDs were observed. Morphologically they were very similar to the appearance of spontaneous (non-surgical) open NTDs. The opened neural tubes were everted progressively and they looked rather flat at 24 hours after surgery. Cellular hyperplasia ('overgrowth' appearance) was noted within 24 hours after surgery and became more prominent during the 24 hours. There was increasing continuity between the surface ectoderm and the neural tissue until 24 hours after surgery when the continuity looked almost complete. In conclusion, surgically induced NTDs are morphologically very similar to spontaneous NTDs.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effects of brefeldin A on hormonally regulated Na+ transport in a model renal epithelial cell line

Na+ transport in renal epithelia is regulated by a wide variety of endogenous and exogenous cellular factors. Although most natriferic agents have an action on the amiloride-sensitive Na+ channel, the biochemical pathways which precede activation of the channel remain incompletely defined. One approach to dissecting such intricate pathways is to perturb a specific cellular process and determine its importance in the postulated mechanism. The current studies examine the effect of brefeldin A (BFA), an inhibitor of the central vacuolar system, on basal as well as aldosterone-, insulin-, and forskolin-stimulated Na+ transport. In the A6 cell line, BFA had a time-dependent effect on basal transport. Aldosterone-induced Na+ transport was sensitive to BFA while insulin's action was only partially blocked and forskolin-stimulated Na+ transport was relatively resistant to the action of the inhibitor. These studies highlight differences as well as points of convergence in the natriferic pathways.

A short sequence upstream of the 5' major splice site is important for encapsidation of HIV-1 genomic RNA

A series of linker scanning and deletion mutations has been constructed in the 5' leader sequence of HIV-1. One virus with a 13-base-linker substitution upstream of the 5' major splice site was as impaired in its ability to replicate as a virus with a large deletion, which included these 13 bases, and was less efficient in packaging its genomic RNA than viruses carrying mutations between the 5' major splice site and the gag translation initiation site. These observations have led to the identification of a conserved pattern of repeated sequence elements associated with sequences experimentally defined as necessary for encapsidation of Moloney murine leukemia virus, spleen necrosis virus, avian leukosis-sarcoma viruses, and human immunodeficiency virus type 1.

Hyperkalemia due to hyporeninemic hypoaldosteronism with liver cirrhosis and hypertension

A 49-year-old man with liver cirrhosis and hypertension was found to have hyperkalemia out of a degree of renal insufficiency and metabolic acidosis with low to normal anion gap, aggravated by volume contraction with diarrhea and medications (captopril, spironolactone and atenolol) interfering with potassium homeostasis. Plasma renin activity and serum aldosterone levels of this patient on a regular diet after discontinuation of medications were very low compared to those of five other cirrhotic patients with normokalemia as controls. Also, the renin-aldosterone stimulation testing on this patient performed by sodium restricted diet and furosemide, upright position and by angiotensin converting enzyme inhibition (captopril, 50 mg) showed the blunted renin and aldosterone responses to each of these stimuli, almost no changes from baseline renin and aldosterone levels, it was concluded that the underlying defect responsible for hyperkalemia in this case was hyporeninemic hypoaldosteronism and this was aggravated by other factors or drugs affecting potassium homeostasis.

[Localization and isozyme patterns of phosphatase in Fibricola seoulensis]

The present study was carried out to investigate the localization and isozyme patterns of acid phosphatase and alkaline phosphatase in metacercariae and in adults of F. seoulensis by enzyme-histochemistry method and electrophoresis. Acid phosphatase showed a strong activity at pH 5 in the intestinal caecum of adults, but showed no reactions in the non-substrate control and in the inhibitor-treated control. Alkaline phosphatase showed a strong activity at pH 8 in the intestinal caecum and the tribocytic organ of adults, and in the intestinal caecum and in the genital anlagen of metacercariae. In non-denature PAGE, ten bands of protein fraction from the extracts of metacercariae and twenty-two bands from adults were detected. In denature PAGE, two protein bands having molecular weights of 192 kDa and 123 kDa were detected in the metacercariae, but absent from adult stage. In adults, protein fractions of 27.5 kDa, 24.5 kDa, 21.4 kDa, 18 kDa, 16 kDa and 15 kDa were detected. In non-denature PAGE, isozymes of acid phosphatase showed the most strong activity at pH 5, whereas no activity was shown at pH 2 and pH 7. One isozyme band (62 kDa) of AcPase was recognized in metacercariae and 4 isozyme bands (95 kDa, 85 kDa, 73 kDa and 62 kDa) in adults.

Increased span of oxido-reduction states between pyridine nucleotide and cytochrome c oxidase in the regenerating rabbit liver as measured by arterial ketone body ratio and near-infrared spectroscopy

Oxido-reduction states of intramitochondrial pyridine nucleotide and cytochrome c oxidase and oxygen saturation of hemoglobin in the regenerating rabbit liver were studied with arterial ketone body ratio and tissue near-infrared spectroscopy. Arterial ketone body ratio (acetoacetate/beta-hydroxybutyrate), which reflects the oxido-reduction states of the intramitochondrial pyridine nucleotide (NAD+/NADH), was reduced from the control value of 0.93 +/- 0.09 to 0.42 +/- 0.03 12 h after 70% hepatectomy, while the oxido-reduction states of cytochrome c oxidase and the oxygen saturation of hemoglobin did not change. The velocity of ATP synthesis, as measured by state 3 respiration and ADP/O ratio in isolated mitochondria, increased by 61.4% 24 h after hepatectomy. These results support the near-equilibrium theory that an increased span in oxido-reduction state between pyridine nucleotide and cytochrome c oxidase drives mitochondrial ATP synthesis.

Rapid identification of streptomycetes by artificial neural network analysis of pyrolysis mass spectra

An artificial neural network was trained to distinguish between three putatively novel species of Streptomyces using normalised, scaled prolysis mass spectra from three representative strains of each of the taxa, each sampled in triplicate. Once trained, the artificial neural network was challenged with spectral data from the original organisms, the 'training set', from additional members of the putative novel taxa and from over a hundred strains representing six other actinomycete genera. All of the streptomycetes were correctly identified but many of the other actinomycetes were mis-identified. A modified network topology was developed to recognise the mass spectral patterns of the non-streptomycete strains. The resultant neural network correctly identified the streptomycetes, whereas all of the remaining actinomycetes were recognised as unknown organisms. The improved artificial neural network provides a rapid, reliable and cost-effective method of identifying members of the three target streptomycete taxa.

Abnormalities of sympathetic innervation in the area of an injured peripheral nerve in a rat model of neuropathic pain

Using the rat model that we have developed, a potential underlying mechanism for sympathetically maintained neuropathic pain (SMP) was explored. In rats showing neuropathic pain behaviors after a tight ligation of the L5 spinal nerve, putative sympathetic postganglionic fibers were examined in the injured spinal nerve and the dorsal root ganglion (DRG), using immunohistochemical staining with antibody against tyrosine hydroxylase (TH). In the neuropathic rats, there was an increase in the number of TH-immunolabeled fibers in the spinal nerve, and some DRG cells were surrounded by the labeled fibers. These abnormalities of sympathetic postganglionic innervation of the injured spinal nerve or the DRG may be a part of the mechanisms underlying the development of SMP.

Ischemically mediated sustained monomorphic ventricular tachycardia. Resolution with anti-ischemic therapy

We describe a patient with ischemically mediated sustained monomorphic ventricular tachycardia occurring at rest and resistant to treatment with intravenously administered procainamide. Percutaneous transluminal coronary angioplasty was initially successful, but rest angina and ventricular tachycardia, resistant to procainamide therapy, recurred 2 weeks later and responded to aggressive anti-ischemic medical therapy. We suggest that anti-ischemic medication may be of benefit in patients with malignant ventricular arrhythmias precipitated by spontaneous myocardial ischemia.

Expression of cellular oncogenes in human gastric carcinoma: c-myc, c-erb B2, and c-Ha-ras

Expression of oncogenes in gastric cancer tissue was evaluated with immunohistochemical staining methods using monoclonal antibodies to products of the oncogenes. Rates of expression in gastric cancer tissue were 50% for c-myc, 72% for c-erb B2, and 56% for c-Ha-ras oncogenes. Expression of these oncogenes in gastric cancer was not correlated with the histologic differentiation. The c-Ha-ras oncogene was positive in 19 of 26 cases with lymph node and/or distant metastasis: the positive rate was significantly higher than in cases without metastasis. Results suggest that c-Ha-ras oncogene is related to the prognosis of gastric cancer. The rate of expression of c-myc and c-Ha-ras oncogenes in gastric cancer tissues was higher in the DNA aneuploid group than in the DNA diploid group. Expression of c-myc and c-Ha-ras oncogenes correlated with other prognostic factors such as DNA ploidy pattern and metastasis. These oncogenes can be used to evaluate prognosis of gastric cancer patients.

Spinal congenital dermal sinus--experience of 5 cases over a period of 10 years

Spinal congenital dermal sinus (CDS) is a rare entity which supposedly results from the failure of the neuroectoderm to separate from the cutaneous ectoderm during the process of neurulation. The lesions are most frequent at the lumbosacral followed by the occipital region. CDS of the thoracic region is very rare. The patients with spinal CDS present with meningitis and/or mass effect from the associated inclusion tumor. They are usually dermoid or epidermoid cysts. Teratoma is rarely associated. The authors experienced 5 cases of spinal CDS over a 10 year period. Of the 5 cases, 2 were at thoracic and 3 were at lumbosacral levels. Dermoid cyst, epidermoid cyst and teratoma were associated in one case each. Two cases presented with neurological deficit and meningitis while an additional case presented with neurological deficit and a history of probable meningitis. Pain was present in 2 cases. Magnetic resonance imaging played an important role in the diagnosis of the lesion and planning of surgery. All the cases showed a good response to surgery even though one patient had persistent neurological deficit.

Cerebral aspergillosis in immunologically competent patients

Aspergillosis of the central nervous system is a rare disease, especially if the patient's immune system is not compromised. The authors report three cases of cerebral aspergillosis in the immunocompetent state: a rhinocerebral form in a diabetic patient, a direct extension from chronic Aspergillus otitis media, and a postoperative Aspergillus brain abscess after brain tumor surgery. In spite of the poor prognosis of cerebral aspergillosis, two of the patients survived. The pathogenesis, predisposing factors, radiologic findings including magnetic resonance image, and the outcome are presented. The pertinent literature of cerebral aspergillosis is also reviewed.

A physiological and system analysis hybrid pharmacokinetic model to characterize carbon tetrachloride blood concentrations following administration in different oral vehicles

Oral absorption of chemicals can be influenced significantly by the administration vehicle or diluent. It has been observed that the oral absorption of carbon tetrachloride (CCl4) and other volatile organic chemicals is markedly affected by the dosing vehicle, with administration in oils producing erratic blood concentration-time profiles with multiple peaks. Analysis of this type of data by a compartmental modeling approach can be difficult, and requires numerous assumptions about the absorption processes. Alternatively, a system analysis method with few assumptions may provide a more accurate description of the observed data. In the current investigations, a nonlinear system analysis approach was applied to blood CCl4 concentration-time data obtained following iv and oral administration. The oral regimens consisted of 25 mg CCl4/kg body wt given as an aqueous emulsion, in water, as pure chemicals, and in corn oil. The system analysis procedure, based upon a disposition decomposition method, provided an absorption input rate function, F, for each regimen. A physiological pharmacokinetic model, based primarily on parameters available in the literature, and the F input functions, formed a hybrid model that adequately described the observed blood CCl4 concentration-time data. The same physiological pharmacokinetic model, employing conventional first-order absorption input schemes, did not predict the data as well. Overall, the system analysis approach allowed the oral absorption of CCl4 to be characterized accurately, regardless of the vehicle. Though system analysis is based on general mathematical properties of a system's behavior rather than on its causal mechanisms, this work demonstrates that it can be a useful adjunct to physiological pharmacokinetic models.

CT diagnosis of superior vena cava syndrome: importance of collateral vessels

OBJECTIVE

The purpose of this study was to evaluate the importance of collateral vessels in the CT diagnosis of superior vena cava syndrome.

MATERIALS AND METHODS

Forty-seven patients with CT evidence of obstruction or compression of the superior vena cava or its major tributaries were included in this study. Contrast-enhanced CT scans had been obtained with a combined bolus and drip-infusion technique. We evaluated the CT scans, with particular attention to the presence of collateral vessels (and if present, their location), without knowing the patients' clinical histories. On reviewing the patients' charts, we found 23 patients with signs or symptoms of superior vena cava syndrome. We then correlated the presence of collateral vessels with the presence of signs and symptoms of superior vena cava syndrome. To verify the frequency of visible collateral vessels in healthy subjects, we also evaluated CT scans of 50 control subjects who did not have mediastinal disease or signs and symptoms of superior vena cava syndrome.

RESULTS

Collateral vessels were seen on CT scans in 24 patients. Among the 23 patients who had signs and symptoms of superior vena cava syndrome, 22 patients had CT scans that showed collateral vessels. Two cases were false-positive and one was false-negative. The presence of collateral vessels, regardless of the number and location of the vessels shown on CT scans, was highly accurate as a predictor of superior vena cava syndrome, with a sensitivity of 96% and a specificity of 92%. Collateral vessels were seen in three (6%) of the 50 control subjects.

CONCLUSION

We conclude that the presence of collateral vessels is a highly sensitive and specific CT sign of superior vena cava syndrome.

A phase III randomized study of 5-fluorouracil and cisplatin versus 5-fluorouracil, doxorubicin, and mitomycin C versus 5-fluorouracil alone in the treatment of advanced gastric cancer

BACKGROUND

With the introduction of cisplatin-containing regimens in the treatment of advanced gastric cancer, promising clinical results have been reported. A 61.5% response rate was observed with a combination of 5-fluorouracil (5-FU) infusion and bolus cisplatin; however, the superiority of cisplatin-containing regimens to other regimens has not been clearly verified in any randomized controlled studies. A prospective, randomized study of 5-FU and cisplatin (FP) versus 5-FU, doxorubicin, and mitomycin C (FAM) versus 5-FU alone (FU) in previously untreated patients with advanced gastric cancer is reported.

METHODS

A total of 324 patients were entered into the trial and 295 patients (103 for FP, 98 for FAM, 94 for FU) were evaluable. The patients were randomized to receive FP, FAM, or FU after stratifying by the following factors: performance status, presence of measurable disease, and resection of the primary tumor.

RESULTS

The overall response rate for patients with measurable disease in the FP arm was significantly higher than in the FAM and FU arms (51% for FP; 25% for FAM; 26% for FU). The durations of response for each arm, however, were not significantly different. Even though the median time to progression for the FP arm (21.8 weeks) was longer than that for the FAM arm (12 weeks; P < 0.05) and for the FU arm (9.1 weeks; P < 0.005), there was no statistical difference in overall survival among the three arms. Toxicity for all three regimens was moderate and consisted primarily of myelosuppression, nausea, vomiting, and alopecia.

CONCLUSIONS

Although the FP regimen showed a significantly higher response rate and a longer time to progression than the FAM or FU regimens, a survival benefit was not observed.