A novel mutation of the DSRAD gene in a Chinese family with dyschromatosis symmetrica hereditaria

Dyschromatosis symmetrica hereditaria (DSH) is a pigmentary genodermatosis of autosomal dominant inheritance characterized by a mixture of hyperpigmented and hypopigmented macules distributed on the dorsal aspects of the hands and feet. It is caused by mutations of the RNA-specific adenosine deaminase gene. We report the identification of a Chinese family with a three-generation pedigree of DSH, in whom a novel tyrosine substitution mutation in DSRAD was demonstrated: a heterozygous nucleotide A-->G transition at position 2879 in exon 10 of the DSRAD gene was detected.

Comparison of the anti-proliferation and apoptosis-induction activities of sulindac, celecoxib, curcumin, and nifedipine in mismatch repair-deficient cell lines

BACKGROUND AND PURPOSE

The adenomatous polyposis coli (APC) and mismatch repair (MMR) pathways are both involved in the tumorigenesis of hereditary colorectal cancers. Chemoprevention focuses on the APC pathway in the absence of information concerning MMR targets. This study compared the anticancer effects of sulindac, celecoxib, curcumin, and nifedipine in MMR-deficient cell lines, in order to determine the most appropriate chemopreventive agent for long-term use in patients with hereditary colorectal cancer.

METHODS

Five human colorectal cell lines (SW480, HCT116, LoVo, SW48, and HCT15) and an endometrial cancer cell line (HEC-1-A) were used for susceptibility testing. Tests included assays for growth inhibition, cell-cycle arrest, and apoptosis.

RESULTS

Sulindac, celecoxib, curcumin, and nifedipine all displayed dose- and time-dependent anti-proliferation activities. Celecoxib was the most effective anti-proliferative agent, and increased the G0/G1 phase proportion in the cell cycle after treatment more significantly than the other agents in all cell lines. Curcumin displayed a more potent apoptosis-inducing activity than the other agents in treated cells.

CONCLUSIONS

The tested drugs were effective against colorectal and endometrial cancer cell lines. Celecoxib is more potent with fewer side effects than sulindac. Nifedipine's observed chemopreventive efficacy may complement its known therapeutic application in patients with hypertension.

Microsatellite instability and hMLH1 and hMSH2 gene expression in Taiwanese hereditary nonpolyposis colorectal cancer

BACKGROUND AND PURPOSE

The mutation rate of hMSH2 and hMLH1 (20%) in Taiwanese hereditary nonpolyposis colorectal cancer (HNPCC) is lower than that reported in other countries. This study aimed to examine the microsatellite instability (MSI) status and gene expression pattern of Taiwanese HNPCC in an effort to establish correlation between these data and results of prior genetic screening.

METHODS

The "Bethesda markers" were used for the MSI analysis. Tumor and neighboring tissues were obtained from 10-mm sections of neutral formalin-fixed, paraffin-embedded, hematoxylin and eosin-stained specimens with a PixCell laser-capture microdissector. Four-mm sections were used for the immunohistochemical analysis by avidin-biotin complex method and final coloring with diaminobenzidine. A pathologist performed scoring of the pathological specimens twice, using a double-blinded methodology. Thirteen tissue blocks from 8 HNPCC families (Amsterdam's criteria) were included in this study.

RESULTS

Although the majority of the HNPCC tissues displayed a MSI-high phenotype (10/13, 76.9%), lack of expression of MSH2 and MLH1 was infrequent. Furthermore, only 1 germ-line mutation was detected in the peripheral blood leukocytes of the patients whose tumors had lost protein expression of MSH2 or MLH1.

CONCLUSIONS

Our results indicate that the pathogenesis of Taiwanese HNPCC is different from that in other countries. Rather than immunohistochemical analysis, MSI status, and genetic screening, clinical history remains a reliable method for diagnosis of HNPCC in Taiwanese the population.

Placenta growth factor elevation in the cord blood of premature neonates predicts poor pulmonary outcome

OBJECTIVE

To determine whether an elevated placenta growth factor (PlGF) level in cord blood is associated with increased risk for preterm infants to develop bronchopulmonary dysplasia (BPD).

METHODS

Sixty-three preterm infants who were born at 34 weeks' gestation or earlier were enrolled. Two infants who died before 28 days' postnatal age could not be assigned a BPD status and were excluded. PlGF levels in cord blood were measured using enzyme-linked immunosorbent assay. Mann-Whitney rank sum test, Spearman correlation coefficients, and multivariable linear or logistic regression analyses were used for statistical analysis.

RESULTS

The BPD group had a higher PlGF level, lower gestational age, lower birth weight (BW), higher incidence of endotracheal tube intubation, and longer duration of intubation. The PlGF levels in cord blood correlated negatively with gestational age and BW. However, multivariable logistic regression analyses revealed that only elevated cord blood PlGF levels and BW were associated with BPD after adjusting for all contributing factors. Furthermore, an increased PlGF level in cord blood was significantly correlated with the clinical severity of BPD, as measured by duration of intubation. At 17 mg/dL, the specificity of cord blood PlGF level in predicting BPD was 95%, the sensitivity was 53%, the positive predictive value was 83%, and the negative predictive value was 82%.

CONCLUSIONS

Measuring cord blood PlGF level at birth might be a biological marker for predicting the occurrence of BPD and allowing early therapeutic intervention.

Expression of angiogenic factors and their receptors in postnatal mouse developing lung

BACKGROUND AND PURPOSE

Several lines of evidence suggest that angiogenesis is necessary for alveolarization and that inhibition of vascular growth during a critical period of early growth may impair alveolarization. However, little is known about the role of angiogenic factors during alveolarization. This study investigated the expression patterns of the Ang-Tie-2 family of endothelium-specific receptor tyrosine kinases and vascular endothelial growth factors and their receptors (VEGF-VEGFR system) during postnatal mouse lung development.

METHODS

The lungs from 3 or 4 mice from groups aged 3, 7, 10 and 14 days and adults were removed and dissected from the main bronchi for reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Semi-quantitative RT-PCR of mouse lung total RNA was used to measure the expression levels of these angiogenic factors and their receptors.

RESULTS

During alveolarization, VEGF/Flk-1, Ang-1, Ang-2, and Tie-2 were up-regulated and PlGF/Flt-1 was kept at a relatively constant level. After alveolarization was completed, PlGF was down-regulated, Flt-1 was up-regulated, and VEGF/Flk-1, Ang-1, Ang-2, and Tie-2 were maintained at relatively high levels.

CONCLUSIONS

During alveolarization, in mice, VEGF/Flk-1, Ang-1, Ang-2, and Tie-2 are up-regulated and PlGF/ Flt-1 is kept at relatively constant level to promote pulmonary microvascular development. In the adult mouse lung, when most of the vascular network is complete, PlGF is down-regulated and Flt-1 is up-regulated to stop angiogenesis and VEGF/Flk-1, Ang-1, Ang-2 and Tie-2 are kept at relatively high levels to maintain mature pulmonary microvasculature.

Overexpression of placenta growth factor contributes to the pathogenesis of pulmonary emphysema

To examine the role of placenta growth factor (PlGF) in the pathogenesis of pulmonary emphysema, we generated PlGF-transgenic (TG) mice using a phosphoglycerate kinase promoter. This resulted in constitutive overexpression of PlGF. In these TG mice, pulmonary emphysema, with enlarged air spaces and enhanced pulmonary compliance, first appeared at 6 months of age and became prominent at 12 months. Increased alveolar septal cell apoptosis was noted in their lungs. Fluorescence-activated cell sorter analysis suggests that these apoptotic septal cells are type II pneumocytes. At the same time, the messenger RNA of vascular endothelial growth factor and platelet-endothelial cell adhesion molecule-1, an endothelial cell marker, were downregulated indicating a reduced number of endothelial cells and its survival factor VEGF. In vitro, exogenous PlGF can inhibit the proliferation and promote the cell death of mouse type II pneumocytes. In normal newborn mice, abundant expression of PlGF messenger RNA was detected in the lungs during saccular division but was rapidly downregulated after alveolarization was complete. Thus, a persistently elevated PlGF was detrimental to the developed lung and causes the emphysematous change seen in our TG mice. Our study suggests that PlGF plays an important role in the pathogenesis of pulmonary emphysema via its action on type II pneumocytes.

Efficacy of Pentasa tablets for the treatment of inflammatory bowel disease

BACKGROUND AND PURPOSE

The Eudragit S formulation of delayed-release 5-aminosalicylic acid (5-ASA), Asacol tablets (AT), has limited efficacy in maintaining remission in patients with inflammatory bowel disease (IBD). This study evaluated the effect of switching patients with unsatisfactory results under treatment with AT to a microgranule delayed-release formulation of 5-ASA, Pentasa tablets (PT).

METHODS

A 12-week, open drug-switching study was conducted in 15 IBD patients, including 9 with ulcerative colitis (UC) and 6 with Crohn's disease (CD) who were evaluated at the time of switching from routine AT (2.4 g/day) treatment (for more than 3 months) to PT (4 g/day). UC patients were those under AT remission maintenance and they were defined as prone-to-relapse because of endoscopy scores > or = 2. CD patients were those under acute treatment with AT who had not attained a complete remission. The primary endpoint was the change in UC Disease Activity Index (UC-DAI) or the CD Activity Index scores after switching to PT therapy. Drug safety profile and patient acceptability were secondary endpoints.

RESULTS

Twelve weeks after switching to PT treatment, the mean (+/- SEM) UC-DAI score was reduced significantly, from 8.18 +/- 0.58 to 6.81 +/- 0.72 (p = 0.013) in UC patients. Subcategory scores indicated improvements in endoscopy scores and in physician global assessment. Though the change in clinical outcomes did not reach significance for CD patients, a trend towards a therapeutic benefit was observed. No adverse event was observed during the 12-week clinical trial.

CONCLUSION

PT may provide a better alternative for IBD patients with unsatisfactory response to AT therapy.

Identification of a locus for porokeratosis palmaris et plantaris disseminata to a 6.9-cM region at chromosome 12q24.1-24.2

BACKGROUND

Porokeratosis palmaris et plantaris disseminata (PPPD) is a rare autosomal dominant dyskeratotic disorder characterized by a cornoid lamella with parakeratosis, hyperkeratosis and loss of granular layers. The genetic basis of this disease is still unknown. Two loci for disseminated superficial actinic porokeratosis (DSAP) were found to be located on 12q23.2-24.1 and 15q25.1-26.1. Both PPPD and DSAP are disseminated types of porokeratosis.

OBJECTIVES

To locate the locus for PPPD, thereby facilitating the identification of this disease gene and leading to an understanding of the pathogenesis of porokeratosis.

METHODS

Genotyping was performed in a Chinese family with PPPD using polymorphic microsatellite markers on 12q and 15q.

RESULTS

The locus for PPPD is located within a 6.9-cM region between markers D12S1613 and D12S1341, with a maximum two-point LOD score of 8.14 (theta = 0.00) at D12S1335.

CONCLUSIONS

This study provides a map location for isolation of a gene causing PPPD.

Clinical characteristics of Taiwanese hereditary non-polyposis colorectal cancer kindreds

BACKGROUND AND PURPOSE

The prevalence of colorectal cancer in Taiwan has increased gradually in recent years. Around 5% to 15% of colorectal cancer is hereditary, and hereditary nonpolyposis colorectal cancer (HNPCC) is the most common form of hereditary colorectal cancer. This study aimed to determine the clinical characteristics of Taiwanese HNPCC kindreds.

PATIENTS AND METHODS

We reviewed the chart records of all HNPCC kindreds followed-up in our hospital during the period from 1996 to 1999. Their clinical characteristics were recorded and analyzed.

RESULTS

There were 10 families, including a total of 202 persons, who met the Amsterdam criteria for HNPCC. Fifty-two persons in these families had a diagnosis of cancer, including 26 women and 26 men. There were 40 colorectal cancers, five endometrial cancers, five gastric cancers, two ovarian cancers, two hepatocellular carcinomas, and one each of lung cancer, breast cancer, thyroid cancer, and pancreatic cancer (six patients had two cancers). The mean age at cancer diagnosis was 42.1 years. Among the 12 occurrences in 11 colorectal cancer patients with complete clinical and pathological findings, most cancers (67%) were located proximal to the splenic flexure (right-side colon). One patient had metachronous colorectal cancer.

CONCLUSIONS

This is the first report of the general clinical characteristics of Taiwanese HNPCC. The clinical characteristics of HNPCC in Taiwan were similar to those in Western countries. The genetic bases of Taiwanese HNPCC patients remain to be determined.

Diagnosis and management of respiratory tract infections for the primary care physician

Respiratory tract infections cause nearly half of deaths owing to infectious disease in the United States. This article has discussed the management of several common respiratory tract infections, with an emphasis on appropriate diagnosis and use of antimicrobial agents. Understanding the cause of various respiratory tract infections enables primary care physicians to avoid unnecessary antibiotic use, decreasing adverse effects owing to medications and preventing the rise in antimicrobial resistance.

Spa contributes to the virulence of type 18 group A streptococci

Streptococcal protective antigen (Spa) is a newly described surface protein of group A streptococci that was recently shown to evoke protective antibodies (J. B. Dale, E. Y. Chiang, S. Liu, H. S. Courtney, and D. L. Hasty, J. Clin. Investig. 103:1261--1268, 1999). In this study, we have determined the complete sequence of the spa gene from type 18 streptococci. Purified, recombinant Spa protein evoked antibodies that were bactericidal against type 18 streptococci, confirming the presence of protective epitopes. Sera from patients with acute rheumatic fever contained antibodies against recombinant Spa, indicating that the Spa protein is expressed in vivo and is immunogenic in humans. To determine the role of Spa in the virulence of group A streptococci, we created a series of insertional mutants that were (i) Spa negative and M18 positive, (ii) Spa positive and M18 negative, and (iii) Spa negative and M18 negative. The mutants and the parent M18 strain (18-282) were used in assays to determine resistance to phagocytosis, growth in human blood, and mouse virulence. The results show that Spa is a virulence determinant of group A streptococci and that expression of both Spa and M18 is required for optimal virulence of type 18 streptococci.

[The use of two-route Cisplatin chemotherapy in the treatment of oral squamous cell carcinoma]

OBJECTIVE

To study the feasibility and efficacy of two-route cisplatin chemotherapy for locally advanced squamous cell carcinoma of oral cavity.

METHODS

23 cases with clinical advanced biopsy-proven oral squamous cell carcinoma received intraarterial chemotherapy with cisplatin (DDP), Pingyangmycin (PYM) and 5-fluorouracilum (5-Fu), at the same time intravenous infusion with natrii thiosulfas (STS) for rescue. DDP at 40-60 mg/d, PYM at 16 mg/d and 5-Fu at 500 mg/d were applied for 5-7 consecutive days.

RESULTS

7 cases (33.3%) obtained a complete response (CR), 11(52.4%) had partial response (PR) with an objective response rate (RR) of 85.7%. No severe toxicity was observed, whereas the most frequent grade I and II drug related toxicities were nausea and vomiting. No nephrotoxicity,hepatotoxicity and severe bone marrow suppression were noted.

CONCLUSION

Two-route cisplatin chemotherapy is, in our experience,a new,effective and safe therapeutic method for oral squamous cell carcinoma.

Endoscopy in acquired immunodeficiency syndrome patients with diarrhea and negative stool studies

BACKGROUND

Diarrhea is a frequent gastrointestinal symptom in patients with acquired immuno-deficiency syndrome (AIDS) and is a major source of morbidity and mortality. A stepwise diagnostic approach is often recommended to search for treatable causes. However, whether the stepwise diagnostic approach is adequate for planning treatment and whether specific treatment for infectious etiologies will affect the survival of patients with AIDS remain unknown.

METHODS

From March 1996 to September 1997, endoscopy was performed in AIDS patients with diarrhea, the etiology of which was not identified by noninvasive methods. Specific treatment was given according to the identified etiologies and symptomatic treatment was given for those without definite diagnosis. The clinical symptoms, signs, and duration of follow-up were recorded and survival patterns were analyzed.

RESULTS

Etiologic diagnoses were made in 26 of 40 patients (65%) who underwent endoscopic studies. Amebic colitis and cytomegalovirus colitis were the 2 leading causes of prolonged diarrhea in patients with AIDS. Thirty-five patients (87.5%) recovered after treatment. The difference in survival time after diarrhea between patients whose symptoms resolved after treatment and those who continued to have diarrhea was statistically significant (p < 0.001).

CONCLUSIONS

Endoscopic studies were helpful for the diagnosis of prolonged diarrhea in AIDS patients who had negative stool studies and did not respond to 2 weeks of empiric treatment. Specific treatment according to the results of endoscopy may improve survival in these patients.

Endoscopic resection of gastrointestinal submucosal tumors

BACKGROUND/AIMS

The occurrence of submucosal tumors in the gastrointestinal tract is not infrequent. According to endoscopic pictures, submucosal tumors can usually be diagnosed without difficulty. However, even with the aid of endoscopic ultrasound, a definite diagnosis is not possible without histological results. Before endoscopy became available, the treatment strategy for gastrointestinal submucosal tumors was either surgery or observation. Due to advances in scientific technology, endoscopic treatment of gastrointestinal submucosal tumors has become increasingly popular. In reviewing the literature, we found that only case reports or small series reports detailing specific tumors in specific locations existed previously.

METHODOLOGY

Endoscopic resection for 12 gastrointestinal submucosal tumors in 11 patients has been successfully performed in our hospital during the past three years.

RESULTS

The group included 5 men and 6 women, ranging in age from 28 to 78 years. The locations of the tumors consisted of 1 in the esophagus, 2 in the stomach, 1 in the jejunum, 5 in the colon and 3 in the rectum. Histological results showed 3 lipomas, 3 carcinoids, 2 leiomyomas, 1 ganglioneuromatous polyp, 1 hemangioma, 1 inflammatory fibroid polyp and 1 myomatous hyperplasia. Bleeding complications occurred in only 2 cases. One stopped spontaneously and the other stopped after epinephrine and sclerosant injection. Only 1 case required a two-step resection in order to avoid perforation. No tumor recurrence was noted during the follow-up period, which ranged from 2 months to 3 years.

CONCLUSIONS

In suitable cases, endoscopic resection of gastrointestinal submucosal tumors can be a safe and valuable method for treating symptomatic tumors and obtaining histological diagnosis of the submucosal tumors.

Bile duct hamartomas. A report of two cases

Bile duct hamartomas (von Meyenburg's complexes) of the liver are usually detected at laparotomy or autopsy as an incidental finding, and usually they are multiple. We report two cases of proved bile duct hamartomas of the liver. The first was in a 65-year-old man whose initial sepsis and many hepatic lesions were interpreted as microabscess of the liver. The second patient was a 39-year-old man, a hepatitis B surface antigen carrier, in whom an incidental hepatic tumor was found. We suggest that liver biopsy be done in hepatic lesions with uncertain clinical features, because the histologic findings may change the treatment plan.

Diagnostic role of endoscopy, stool culture, and toxin A in Clostridium difficile-associated disease

This retrospective study was designed to assess the roles of stool culture for Clostridium difficile, detection of the presence of toxin A, and endoscopic examination in the diagnosis of Clostridium difficile-associated disease (CDAD). From January 1994 through September 1996, there were 213 patients with stool cultures positive for C. difficile in National Taiwan University Hospital. Of these, 126 had CDAD. There were 87 asymptomatic carriers of C. difficile in our study, 12 of whom were positive for toxin A. In addition, seven patients with pseudomembranous colitis (PMC), who were either culture-negative or not tested, were included in the study. The positive predictive values of stool cultures for CDAD and PMC were 59% and 32%, respectively. The positive predictive values of toxin A for CDAD and PMC were 41% and 43%, respectively. Seventy-eight patients (59%) improved with supportive treatment after discontinuing antibiotics. We concluded that stool culture for C. difficile and discontinuation of antibiotics should be the standard approach for patients with suspected CDAD. Endoscopic studies can eliminate some other possible causes of diarrhea such as inflammatory bowel disease, allow biopsies of suspicious lesions, and reveal the severity of CDAD. Toxin assay results need to be interpreted together with the clinical data.

Acute pancreatitis complicated by infarction of the spleen and spinal cord

Complications of acute pancreatitis may include local pancreatic necrosis with pseudocyst or abscess formation, and extrapancreatic manifestations such as pulmonary renal, hepatic, endocrine, and coagulation abnormalities. Coagulation abnormalities associated with acute pancreatitis usually present as thrombophlebitis or widespread microthrombi; most occur in the venous or capillary circulation. We report a rare case of acute pancreatitis complicated by pseudocyst formation, splenic vein thrombosis, splenic infarction, and spinal cord infarction, which resulted in paraplegia. An association between acute pancreatitis and spinal cord infarction has not been reported before.

Case report: successful palliative treatment with intraperitoneal OK-432 injection for epithelioid haemangioendothelioma presenting with intractable ascites

Epithelioid haemangioendothelioma is an unusual type of endothelium-derived vascular tumour of borderline malignancy, which has high variability in clinical presentations, depending on the primary site of involvement. We report on a 20-year-old woman who presented with progressive abdominal fullness for 6 months. Multiple lung and liver nodules with pleural effusion and profuse ascites were found. The diagnosis of epithelioid haemangioendothelioma was made after wedge biopsy of the liver. The ascites was intractable and refractory to strong diuretic therapy and repeated paracentesis. Therefore, six courses of intraperitoneal injection of OK-432 were administered. The ascites subsided to a minimal amount after treatment and the patient remained symptom-free for approximately 8 months. The ascites recurred later and another three courses of intraperitoneal injection of OK-432 were administered. The ascites disappeared again. The patient has remained symptom-free since the end of the second period of treatment.

Rotation and gray-scale transform-invariant texture classification using spiral resampling, subband decomposition, and hidden Markov model

This paper proposes a new texture classification algorithm that is invariant to rotation and gray-scale transformation. First, we convert two-dimensional (2-D) texture images to one-dimensional (1-D) signals by spiral resampling. Then, we use a quadrature mirror filter (QMF) bank to decompose sampled signals into subbands. In each band, we take high-order autocorrelation functions as features. Features in different bands, which form a vector sequence, are then modeled as a hidden Markov model (BMM). During classification, the unknown texture is matched against all the models and the best match is taken as the classification result. Simulations showed that the highest correct classification rate for 16 kinds of texture was 95.14%

[Cerebrovascular emergencies: difficulties and errors in diagnosing various stroke types]

The frequency of and reasons for errors in diagnosing various types of cerebrovascular disease at the emergency room of National Cheng Kung University Hospital were analyzed in 548 consecutive patients from January to December 1990. Each patient was evaluated by neurological residents and a bedside diagnosis was made on the basis of history-taking, physical examination, and diagnostic reasoning. The emergency diagnosis was made after finishing the radiological and/or laboratory investigations. The tentative emergency diagnosis of each patient was judged as correct or not by comparison with the final diagnosis, which was based on either the results of specific investigation or on the typical cerebrovascular syndrome ascertained by the attending physicians if the specific investigation was not helpful. If the tentative emergency diagnosis had been judged to be wrong, the cause for the misdiagnosis was determined by reviewing the records of the entire diagnostic process. The diagnosis in the emergency setting was erroneous in 131 (24%) patients. Primary intraventricular hemorrhage, cerebral venous thrombosis and subarachnoid hemorrhage were frequently misdiagnosed as compared with other types of stroke. The explored reasons for diagnostic inaccuracy were: inadequate basic data (46%), reasoning errors (38%), and lack of fundamental knowledge (16%). These results implied that the education and training for diagnosis of subarachnoid hemorrhage in emergency should be enhanced. Deeply comatose states caused diagnostic difficulties in data collection. Diagnostic errors were frequently encountered in unusual stroke or stroke with atypical presentations. To increase diagnostic ability in cerebrovascular emergencies, residents should strive to improve interview and examination skills and reasoning discipline. Modern technology is not a panacea for diagnostic difficulties.(ABSTRACT TRUNCATED AT 250 WORDS)

Bedside diagnosis for neurological residents in neurological emergencies: a retrospective analysis

BACKGROUND

Critical assessment of diagnostic accuracy is indispensable to resident training and medical education, especially in regard to our situation of the extremely low rate of autopsy. Recent setup of advanced technology for neurological diagnosis has resulted in a tendency to overuse these tools at the expense of using classic bedside diagnostic approach. Disclosing the common errors of daily practices among neurological residents necessitates implementing this pioneer study.

METHODS

The tentative diagnosis of each patient, as performed by neurological residents after finishing bedside diagnostic processes, was assessed by final diagnosis concluded from clinical syndrome and/or the results of laboratory studies. The overall rate of diagnostic error and the frequency of diagnostic inaccuracy in various disease entities were evaluated. The reason for the diagnostic error was determined by reviewing the records regarding the entire diagnostic process.

RESULTS

1336 consecutive patients from January 1990 to December 1990 were recruited for this study. The initial bedside diagnosis was correct in 901 (67%) patients. No definite final diagnosis could be obtained in 169 (13%) patients. The diagnoses were incorrect in 266 (20%) patients. The highest rate of inaccuracy was found in the diagnosis of subdural hematoma (56%). The other common diseases of high rate of diagnostic inaccuracy were myasthenia gravis (50%), subarachnoid hemorrhage (42%), Guillain-Barré syndrome (40%), traumatic disorders (39%), herniation of intervertebral disc (33%), metabolic encephalopathy (30%), infection of central nervous system (30%), intracranial neoplasm (24%), drug overdose or intoxication (22%), and mixed neurological and metabolic encephalopathy (21%). The explored reasons for diagnostic inaccuracy were errors of reasoning (38%), inadequate data base (35%), and inadequate fund of knowledge (27%).

CONCLUSIONS

This study confirmed that the basic methods of bedside diagnosis with a standardized sequence of history taking, physical examination and diagnostic reasoning are currently still the most fundamental process of achieving an accurate diagnosis in neurological emergencies. No shortcut or mechanical substitute is available for clinical diagnosis.

Brain L-glutamate decarboxylase: purification and subunit structure

Glutamate decarboxylase (GDCase; L-glutamate-1-carboxy-lyase, EC 4.1.1.15) was purified from whole rat brain approximately equal to 1300-fold to apparent homogeneity with a specific activity of 2.4 units per mg of protein by a combination of column chromatographies on DEAE-cellulose, hydroxylapatite, and gel filtration, and preparative nondenaturing polyacrylamide gel electrophoresis. The purified preparation contained a single protein band that comigrated with GDCase activity in three diverse analyses: nondenaturing regular (5%) and gradient (3.6-25%) polyacrylamide gel electrophoresis and isoelectric focusing at pH 4-7. The native molecular mass was calculated to be 120 +/- 10 kDa from gradient polyacrylamide gel electrophoresis and 110 +/- 10 kDa from gel filtration. Under the treatment with NaDodSO4 and 2-mercaptoethanol, GDCase dissociated into two subunits of 40 +/- 2 and 80 +/- 4 kDa, as estimated from NaDodSO4 gel electrophoresis. However, only a 40-kDa subunit was detected when GDCase was treated with 4 M urea plus NaDodSO4 and 2-mercaptoethanol, suggesting that the 80-kDa subunit is the dimer of the 40-kDa subunit. In immunoblotting, polyclonal antibodies against GDCase reacted with both 40- and 80-kDa subunits, while monoclonal antibody reacted with only 80-kDa subunits. The isoelectric point of the native enzyme was 5.4. The Km for glutamate was 1.59 X 10(-3) M. In addition to L-glutamate, cysteine sulfinic acid was also decarboxylated at approximately equal to 10% of the rate of glutamate. The pH optimum was fairly broad, with a maximum at approximately equal to 7.3. The enzyme was strongly inhibited by carbonyl-trapping agents, sulfhydryl reagents, thiol compounds, and beta-methylene-DL-aspartate.

Production and characterization of polyclonal and monoclonal antibodies to rat brain L-glutamate decarboxylase

Specific monoclonal and polyclonal antibodies to rat brain glutamate decarboxylase (GAD) were produced and characterized. Polyclonal antibodies against GAD were raised in rabbits by injecting a total of 70-210 micrograms of purified GAD i.m. The specificity of anti-GAD serum was established from a variety of tests including Ouchterlony immunodiffusion, immunoelectrophoresis, immunoprecipitation, dot immunoassay, ELISA tests and Western immunoblottings. In immunodiffusion and immunoelectrophoresis tests using partially purified GAD preparations and anti-GAD serum a single, sharp precipitin line corresponding to GAD activity was obtained. Quantitative immunoprecipitation of GAD activity was achieved using anti-GAD IgG and Staphylococcus aureus. Specificity of the antiserum was further indicated from a dot immunoassay and ELISA tests in which the intensity of the reaction product was proportional to the amount of GAD protein present. In the Western immunoblotting experiments using partially purified GAD preparations only two protein bands corresponding to the position of the two subunits of GAD were stained by anti-GAD IgG, further supporting the specificity of polyclonal antibodies against GAD. In addition to polyclonal antibodies, several specific GAD-antibodies-producing clones were also obtained by the hybridoma technique. The specificity of monoclonal antibodies against GAD were established from the following criteria: positive on ELISA test using homogeneous GAD as antigen; formation of GAD--anti-GAD IgG complex as indicated from gel filtration chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis; and specific recognition of GAD subunit in a partially purified GAD preparation in Western immunoblotting test. Monoclonal antibodies were further characterized by immunohistochemical localization of known GABAergic neurons and their processes in the cerebellum and retina.

Immunochemical data suggesting a pattern for the evolution of human placental alkaline phosphatase

Hyperimmune absorbed rabbit antisera which were reactive with epitopes specific for individual variants of human placental alkaline phosphatase were tested for their reactivity with primate placental alkaline phosphatases. Using the three epitope-specific reactivities defined previously, we found that: epitope I is present in the S-, D- and I-variants of human placental phosphatase, and in the chimpanzee and pygmy chimpanzee placentae; epitope II is present in the F- and 17-variants, and in the Nagao isoenzyme of human placental alkaline phosphatase, and in some orangutan placentae and all spider monkey placentae tested; epitope III is present in the F- and 17-variants, and the Nagao isoenzyme of human placental alkaline phosphatase, and in all the spider monkey placentae and the single squirrel monkey placenta examined. The binding assay was complemented by a competitive radioimmunoassay, which confirmed that the spider monkey placental samples were binding to the same antibody population which bound the human enzymes. The presence of epitopes characteristic of rare human placental phosphatase variants in these remote primate relatives suggests that the rare variants in the current human population have been present during the entire course of evolution. The presence of both epitopes characteristic of the Nagao isoenzyme in spider monkeys suggests that this variant isoenzyme is closely related to the enzyme present in the primate placenta at the time of species divergence (humans and New World monkeys). A hypothetical scheme for this divergence is proposed.

[Transfer of plasmid RP4 into some phytopathogenic bacteria and its relation to their virulence]

Plasmid RP4 were transferred from Escherichia coli into Pseudomonas solanacerum, Xanthomonas campestris pv. oryzae, X. campestris pv. campestris, and X. campestris pv. citri at the frequencies of 1.8 X 10(-6), 2.8 X 10(-6), 1.4 X 10(-2) and 2.0 X 10(-3), respectively. The frequencies of transfer depended on bacterial species and conjugation conditions. Treatment of bromide at the concentration of 2 micrograms/ml and acridine orange at 100 micrograms/ml for 32 hrs the plasmid RP4 could be cured from the transconjugant of P. solanacerum at the frequencies of 75% and 95%, respectively. When transconjugant of P. solanacearum was inoculated into tomato plants, the decrease in virulence was observed, furthermore, no plasmids were detected both in the wild-type strain and the cured transconjugant. It thus appears that the virulence may not be related to plasmids.

Immunochemical studies of human placental-type variants of alkaline phosphatase. Structural differences between the "Nagao isoenzyme" and the placental "D-variant"

Hyperimmune antisera raised against the rare FD and SD phenotypes of human placental alkaline phosphatase and the related cancer-associated Nagao isoenzyme were exhaustively absorbed with the common SS and FF phenotype enzymes conjugated to Sepharose. The antibodies so obtained had one of three specificities, determined by testing all the common phenotypes of placental alkaline phosphatase, the rare FD, SD and S-17 phenotypes, and five samples of purified cancer patient enzymes: (I) antibodies reactive with the S, D and I variant enzymes, but not with the F, 17 or Nagao enzymes; (II) antibodies reactive with the F, 17 and Nagao enzymes, but not with the S, D, and I variant enzymes; and (III) antibodies reactive with the D, 17 and Nagao enzymes and not with the S, F or I variant enzymes. Based on these data, and on the information obtained from biochemical characterization, it is argued that the Nagao isoenzyme and the D-variant are closely related but distinct enzymes. We propose a hypothetical scheme for the divergence of these two enzymes from a common ancestral gene product. In this scheme, an ancestral gene duplication resulted in two isoenzymes, one of which is completely specific to the placenta, and one of which (the "Nagao isoenzyme") has an unknown normal tissue localization, but is found in some cases of cancer. We use the term "syn-placental" to describe this latter isoenzyme, reflecting its close structural relationship to the placental isoenzyme.

Specificity of allozyme-absorbed antisera to human placental alkaline phosphatase for individual phenotypes

Antisera raised against the rare FD phenotype enzyme were exhaustively absorbed with SS and FF phenotype enzyme immobilized on agarose gels. When it was absorbed with the FF phenotype enzyme, the antiserum no longer reacted with the F-variant enzyme, but did with the S-, D-, and I-variants, as determined by electrophoretic retardation experiments and precipitation of antigen-antibody complexes using staphylococcal protein A. When the antiserum was absorbed with SS phenotype enzyme, it no longer reacted with S-, D-, or I-variant enzyme, but did have some reactivity with the F-variant, as seen in the protein A assay. Based upon the IgG concentration, which bound 40% of the appropriate enzyme, 1/20 of the antiserum preparation was specific for the S-, D-, and I-variant shared specificity, and 1/400 was specific for the F-variant alone.