Cellulosome and noncellulosomal cellulases of Clostridium cellulovorans

This paper reviews the properties of the cellulosome and noncellulosome cellulases produced by Clostridium cellulovorans, an anaerobic, mesophilic, spore-forming microorganism that produces copious amounts of cellulase. The three major subunits of the cellulosome, CbpA, exoglucanase S (ExgS), and P100, are described, as well as the properties of the functional domains of CbpA. The properties of two noncellulosomal endoglucanases, EngD and EngF, are compared. The functions of the cellulose-binding domain (CBD) of CbpA indicate its potential uses in biotechnology.

Properties of exgS, a gene for a major subunit of the Clostridium cellulovorans cellulosome

The nucleotide sequence of P70, one of the three major subunits of the Clostridium cellulovorans cellulosome, has been determined. The gene designated as exgS (Genbank Accession No. U34793) consists of 2112 bp and encodes a protein containing 703 amino acids with a molecular mass of 77.7 kDa. ExgS has a putative signal peptide sequence of 32 amino acids. The N-terminal region is separated from the C-terminal region by a short-Pro-Thr-Pro linker. The C-terminal region of ExgS contains a duplicated sequence (DS), each sequence consisting of 22 amino acids. exgS, located 67 bp downstream of cbpA in the chromosome, is immediately upstream of a gene encoding a family 9 type endoglucanase that we have designated as EngH. This gene cluster to date consists of regA-cbpA-exgS-engH. Recombinant ExgS (rExgS) containing no signal peptide was expressed in E. coli. The rExgS actively digested several forms of cellulose, including Avicel, Sigmacell101, crystalline cellulose, and xylan, but not carboxymethyl cellulose (CMC). Cellotetraose was the smallest oligosaccharide substrate for rExgS. The enzymatic studies indicated that ExgS was an exoglucanase and had some properties similar to that of CelS from C. thermocellum and CelF from C.cellulolyticum. An exoglucanase has now been found to be a component of the C. cellulovorans cellulosome as well as the previously reported endoglucanases.

Successful resection of sigmoid colon cancer in a patient with factor XI deficiency

A 42-year-old-women with sigmoid colon adenocarcinoma was found to have isolated prolonged activated partial thromboplastin time (aPTT 102.5 s, normal range 24-36 s) preoperatively. Her medical history included an episode of prolonged postdelivery uterine bleeding 16 years previously. A mixed aPTT test showed immediate correction of the prolonged aPTT, indicating a coagulation factor deficiency in the intrinsic pathway. Factor assays showed factor XI was below 1% of average normal value whereas factor VIII, IX and XII activities were normal. Family screening revealed one sister among the three siblings also had isolated prolonged aPTT. The patient was transfused with four units (5mL/kg) of fresh frozen plasma the day before surgery, then with two units during surgery. The operation was uneventful with no bleeding problems. The patient recovered smoothly and is currently undergoing adjuvant chemotherapy. This is the first formal report of a patient with factor XI deficiency undergoing major surgery in Taiwan. Careful monitoring of aPTT, with fresh frozen plasma transfusion, when needed, may safely overcome bleeding problems during surgery.

The resolvase encoded by Xanthomonas campestris transposable element ISXc5 constitutes a new subfamily closely related to DNA invertases

BACKGROUND

Conservative site-specific recombination is responsible for the resolution of cointegrates which result during the transposition of class II transposable elements. Resolution is catalysed by a transposon-encoded recombinase, resolvase, that belongs to a large family of recombinases, including DNA invertases. Resolvases and the related invertases are likely to employ similar reaction mechanisms during recombination. There are important differences, however. Resolvases require two accessory DNA binding sites within each of the two directly repeated recombination sites. Invertases instead need a host factor, Fis, and an enhancer type DNA sequence, in addition to two inversely orientated recombination sites.

RESULTS

The resolvase encoded by transposable element ISXc5 from the gram-negative phytopathogen Xanthomonas campestris shows two features which distinguish it from other known resolvases. First, it is more closely phylogenetically related to invertases than other resolvases. In particular, two functionally important regions seem highly conserved between this resolvase and members of the invertase subfamily. Second, the enzyme exhibits a large extension of its carboxy-terminal domain with unknown function. We purified ISXc5 resolvase and analysed its resolution reaction in vitro. Our biochemical and DNA topological analysis reveals that critical features of resolution are similar, if not identical, to that carried out by gammadelta resolvase. However, despite its apparent similarity to invertases, we were unable to detect recombination on standard substrates for DNA inversion, in either the presence or absence of Fis.

CONCLUSIONS

ISXc5 resolvase employs a reaction mechanism which is common to members of the resolvase family. Its position near the evolutionary borderline to invertases and its high degree of identity within two functionally important regions with members of the DNA invertase subfamily suggest that only a few replacements of critical residues may suffice to convert this resolvase into a functional, possibly Fis-dependent invertase.

Risk factors analysis for early fatality in children with acute bacterial meningitis

To identify the cause of early fatality and to delineate the clinical findings on admission associated with this early fatality, a retrospective study of 101 children with bacterial meningitis was performed in southern Taiwan. Risk factors for early fatality are compared between patients with and without acute death in the first 3 days after admission. The overall patient fatality is 27%. Eighty-five percent of them (23 patients) occur at an average of 16.5 hours after admission despite proper antibiotic treatment. The causes of early death are predominantly hemodynamic in 14 patients (61%) and predominantly neurologic in nine (39%). Analysis of clinical parameters available on admission indicated a significant risk of early death in patients who have tachycardia, tachypnea, hypothermia, poor skin perfusion, metabolic acidosis, leukopenia, thrombocytopenia, low cerebrospinal fluid leukocyte count, and high cerebrospinal fluid lactate level. Multivariate analysis demonstrates that metabolic acidosis, poor skin perfusion, and low cerebrospinal fluid leukocyte count are independently and significantly associated with early fatality. In conclusion, two thirds of early fatalities in children with bacterial meningitis are the result of septic shock. Close surveillance for signs of septic shock, as well as of brain herniation should be continued, especially within 3 days after antibiotic treatment.

Lymph node metastasis in squamous cell carcinoma of the intrathoracic esophagus

BACKGROUND

In esophageal carcinoma lymph node metastasis is one of the most important factors of prognosis. This prospective study evaluated the incidence and extent of lymph node metastasis, and assessed the relationship between the depth of tumor invasion and lymph node metastasis in esophageal carcinoma.

METHODS

Between 1985 and 1996, tissue samples from 112 patients undergoing radical esophagectomy and gastric substitution for squamous cell carcinoma of the intrathoracic esophagus were collected. Patients with distant organ metastasis were excluded. All specimens were evaluated and sent for histopathologic examination.

RESULTS

In 108 men and four women with a mean age of 63.1 years, the average number of dissected lymph nodes in one surgical procedure, was 30 per person. The most commonly involved nodes were the periesophageal (42.9%) and the perigastric (42.9%) nodes, followed by the recurrent laryngeal nerve (23.8%) and thoracic paratracheal (22.2%) nodes. For tumors in the upper third of the esophagus, the most frequently involved nodal groups were the periesophageal (28.6%) and the paratracheal (28.6%) nodes, followed by the recurrent laryngeal nerve (21.4%) the deep cervical (21.4%), and the perigastric (21.4%) nodes. For tumors in the middle third of the esophagus, the periesophageal nodes (27.3%) were most commonly involved, followed by the perigastric (18.2%) and the subcarina (10.6%) nodes. For tumors in the lower third of the esophagus, the perigastric lymph nodes (37.5%) were the most common nodal metastatic site, followed by the celiac (18.8%) and the recurrent laryngeal nerve (18.2%) nodes. Depth of tumor invasion was also found to correlate significantly with lymph node metastasis (p = 0.0015).

CONCLUSIONS

Wide lymph node metastasis between the neck and the upper abdomen occurs frequently in squamous cell carcinoma of the esophagus. For potentially curable esophageal carcinomas, en-bloc esophagectomy with complete locoregional lymph node dissection may provide favorable local control of the lesion and more accurate tumor staging.

Effects of an educational program on parents with febrile convulsive children

The purpose of this study was to characterize the effects of an educational program on knowledge, attitude, concern, and first-aid measures among parents with febrile convulsive children. All parents completed a pretest questionnaire 3 weeks before the meeting. The parents were assigned randomly into experimental (n = 65) and control (n = 64) groups on the day they attended the program. The control group completed the identical questionnaire (posttest) before the program, whereas the experimental group completed the same posttest after the program. In pretest, most parents considered electroencephalogram or computed tomography necessary in evaluating their children, suggested that immunization be postponed, and rated the risk of subsequent epilepsy as high for their children. Most of them favored frequent body temperature measurement, were very anxious about further febrile convulsion episodes during the night, and were fever phobic. After education, although only a slight change in fever anxiety was found, the experimental group showed significant improvement in knowledge, attitude, concerns, and anticipatory practice of febrile convulsion compared with the control group. In conclusion the parents' poor knowledge, negative attitudes, anxiety, and inadequate first-aid measures toward febrile convulsion can be effectively improved by an educational intervention program.

Channel formation and [Ca2+]i accumulation induced by perforin N-terminus peptides: comparison with purified perforin and whole lytic granules

Cytotoxic T lymphocytes (CTL) and natural killer (NK) cells express the pore forming protein perforin, which contributes to lymphocytotoxicity. The hallmark of perforin action is opening high-conductance transmembrane channels that enable massive influx of Ca2+ ions (deleterious to many cell types), as well as granzymes, which may trigger the apoptotic pathway. To explore the functional domains in the perforin molecule, we investigated in PN71 lymphocytes, the ability of perforin N-terminus synthetic peptides (compared to purified perforin and perforin-containing lytic granules), to cause intracellular Ca2+ ([Ca2+]i) accumulation and open transmembrane channels. To this end, we used the whole cell recording technique and Indo 1 fluorescence to measure membrane currents and [Ca2+]i, respectively. We have demonstrated that the N-terminus peptide Hu-34 (amino acids 1-34) closely resembled perforin action, reflected by [Ca2+]i accumulation and channel activity, while shorter peptides (e.g., Hu-16) generated mostly short-lived channels but no [Ca2+]i elevation. Hence, the first 34 amino acids of the perforin N-terminus sequence are sufficient for the perforin action.

Laryngeal candidiasis in children

Candidiasis of the larynx is rare and often related to immunocompromised hosts. We here report a case of laryngeal candidiasis in an immunocompetent infant. The diagnosis was obtained by direct fibre-optic laryngoscopy with specimens submitted for culture. He received anti-fungal medication and was quite well at 1-year follow up. The pertinent literature is also reviewed.

Using monoclonal antibodies to characterize a sequential epitope on the group I allergen of Bermuda grass pollen

BACKGROUND

Cyn d 1, the group I allergen of Bermuda grass pollen, had been purified and characterized.

METHODS

A sequential B cell epitope on Cyn d 1 was studied with monoclonal antibodies (MoAbs). Cyn d 1 was cleaved by Achromobacter protease I into fragments, and the resulting peptides were fractionated on reversed-phase columns before being reacted with anti-Cyn d 1 MoAbs in a radioimmunoassay. A Cyn d 1 fragment recognized by its MoAb was selected for Edman degradation. A synthetic peptide was constructed according to the determined sequence.

RESULTS

The epitope on Cyn d 1 recognized by MoAb 18-53 was found to be conformation independent, since its activity was not changed after sodium periodate, guanidine or urea treatment. The enzyme-cleaved fragment containing this epitope was determined to be DVDKPPFDGMTACGNEPIF which corresponds to the N-terminal 46-64 residues of Cyn d 1. The presence of this sequence in the epitope recognized by MoAb 18-53 was demonstrated by enzyme immunoassay and further confirmed by inhibition of binding enzyme immunoassay with synthetic peptides. Some cross-reactivity with the N-terminal 45-63 residues of Lol p 1 was also found.

CONCLUSIONS

The primary structure of a sequential epitope on Cyn d 1 was determined, and its activity was confirmed with peptides synthesized according to the determined sequence.

Cloning and sequence analysis of the gene (eprA1) encoding an extracellular protease from Aeromonas hydrophila

A gene (eprA1) encoding the extracellular protease of Aeromonas hydrophila AH1 has been cloned and sequenced. Nucleotide sequence analysis of eprA1 predicted a single open reading frame (ORF) of 1038 bp encoding a 346 amino acid (aa) polypeptide, with a potential 21-aa signal peptide. When the eprA1 gene was expressed in minicells, one major band of approx. 37 kDa was identified, while protease activity staining experiments identified a caseinolytic band of approx. 29 kDa determined by SDS-PAGE analysis of the minicells. The deduced C-terminal aa region (Arg-290 to Gly-313) showed sequence homology to partial C-terminal sequences of other zinc metalloproteases including Penicillium citrinum metalloprotease (PlnC), Aspergillus oryzae metalloprotease (NpII), Aspergillus flavus metalloprotease (MepA), and Aspergillus fumigatus metalloprotease (Mep20), particularly with respect to zinc-binding residues.

Antibodies against dengue virus E protein peptide bind to human plasminogen and inhibit plasmin activity

Both mice and rabbits immunized with dengue virus E protein peptide spanning amino acids 100-119 (D4E) produced antibodies that reacted not only with the D4E peptide itself but also with human plasminogen, as shown by ELISA and Western blot. Sera from dengue virus-hyperimmunized mice and dengue patients also contained antibodies against D4E and plasminogen. Furthermore, such sera all contained plasmin inhibitory activity. Using affinity-purified anti-D4E antibodies and free D4E peptide for competitive inhibition, we demonstrated that the inhibition of plasmin activity was due to anti-D4E antibodies rather than other substances in the sera. Taken together, these results suggest dengue virus E protein amino acids 100-119 are a cross-reactive immunogenic region, and antibodies against this region may interfere with human fibrinolysis.

Augmentation of protein kinase C activity and liver cell proliferation in lead nitrate-treated rats

It is shown that lead alters calcium mediated cellular processes in several biological systems. Calcium enhances the activity of protein kinase C (PKC) which takes part in eliciting cell mitosis. In this study, the effects of lead nitrate on the activity of PKC enzyme were investigated in rat liver. The PKC activity was determined at 12, 24, 48, 72, 120, 168 hours after treatment with a single dose of lead nitrate in male Wistar rats. The results showed that the specific PKC activity of the purified particulate fraction was increased and reached a maximum at 24 hour, and lasted for 48 hours. This augmented activity of PKC was parallel with the increase of the lead level in the purified particulate fraction, although the protein levels of PKC alpha, PKC delta and PKC zeta were unchanged. Moreover, the frequency of mitotic cells also exhibited a significant increase, and like PKC activity, reached its maximum at 24 hour with accompany signs of liver enlargement. The results suggest that the PKC activation may be involved in promoting liver cell proliferation in lead nitrate-treated rats.

Tumor necrosis factor alpha plays a central role in immune-mediated clearance of adenoviral vectors

Adenovirus (Ad) gene transfer vectors are rapidly cleared from infected hepatocytes in mice. To determine which effector mechanisms are responsible for elimination of the Ad vectors, we infected mice that were genetically compromised in immune effector pathways [perforin, Fas, or tumor necrosis factor alpha (TNF-alpha)] with the Ad vector, Ad5-chloramphenicol acetyl transferase (CAT). Mice were sacrificed at 7-60 days postinfection, and the levels of CAT expression in the liver determined by a quantitative enzymatic assay. When the livers of infected mice were harvested 28 days postinfection, the levels of CAT expression revealed that the effectors most important for the elimination of the Ad vector were TNF-alpha > Fas > perforin. TNF-alpha did not have a curative effect on infected hepatocytes, as the administration of TNF-alpha to infected severe combined immunodeficient mice or to infected cultures in vitro had no specific effect on virus persistence. However, TNF-alpha-deficient mice demonstrated a striking reduction in the leukocytic infiltration early on in the infection, suggesting that TNF-alpha deficiency resulted in impaired recruitment of inflammatory cells to the site of inflammation. In addition, the TNF-deficient mice had a significantly reduced humoral immune response to virus infection. These results demonstrate a dominant role of TNF-alpha in elimination of Ad gene transfer vectors. This result is particularly important because viral proteins that disable TNF-alpha function have been removed from most Ad vectors, rendering them highly susceptible to TNF-alpha-mediated elimination.

Myocarditis with complete atrioventricular block associated with herpes simplex virus infection: report of one case

Myocarditis with complete atrioventricular block is a very unusual complication of the herpex simplex infection. We report a 10-year-old boy infected very likely by the herpes simplex virus and who presented with high fever, erythema multiforme, complete atrioventricular block, and Adams-Stokes seizures. Emergent temporary pacemaker was performed for bradycardia. A sixteen-fold rise in herpes simplex antibody titer by a complement fixation method occurred within two weeks. Normal cardiac rhythm recovered 11 days later with a sequela of complete right bundle branch block after 2 years follow-up.

Prediction of bleeding diathesis in patients undergoing cardiopulmonary bypass during cardiac surgery: viscoelastic measures versus routine coagulation test

BACKGROUND

Severe hemorrhagic tendency often complicates cardiopulmonary bypass (CPB) in cardiac surgery. In this study, we compared the effectiveness of thromboelastography (TEG), Sonoclot (SCT), and routine coagulation test (RCT) in the prediction of coagulation defects.

METHODS

Forty-three patients undergoing cardiac surgery with CPB were included. Blood for RCT, TEG, and SCT profiles was sampled before systemic heparinization and after protamine administration. Clinically significant bleeding was defined as chest tube drainage in excess of 100 ml/h for 3 consecutive hours or 300 ml/h in 1 h. All coagulation parameters obtained before and after CPB were compared. The sensitivity, specificity, accuracy, false positive, and false negative rate were also calculated and compared.

RESULTS

All coagulation tests were within normal range except higher partial thromboplastin time. Variables which were significantly different from those before CPB included platelet count, fibrinogen level, prothrombin time, and thrombin time in RCT, alpha angle and maximum amplitude in TEG, and R2 and peak time in SCT. In the TEG tracing, all variables had high sensitivity, specificity, and accuracy (average 85.4%, 83%, and 83.5% respectively) and low false positive and negative rate (12.5% and 5% respectively). Although SCT had high sensitivity (76.3%) and low false negative rate (6.5%), its specificity and accuracy were all under 50%.

CONCLUSIONS

Our data demonstrated that the TEG monitoring is a useful tool for detecting post-CPB bleeding diathesis and can provide much predictive information. RCT and SCT are of limited value because of higher rate of unreliable results.

Streptococcal toxic shock syndrome complicating varicella in children

The most common complication in children with varicella is cutaneous superimposed infection with pyogenic bacteria. Group A beta-hemolytic streptococci, which are known to cause life-threatening infections in both previously healthy children and those with underlying diseases, are the most frequently associated pathogens. A newly recognized disease, called streptococcal toxic shock syndrome, is associated with severe morbidity and mortality. We report a 3-year-old boy with a diagnosis of this syndrome who presented with increasing fever, vomiting, and lethargy 7 days after the development of a classic varicella skin lesion. In spite of aggressive fluid supply, administration of inotropic agents, and cardiopulmonary resuscitation, a rapidly deteriorating clinical course led to death 4 hours after hospitalization. This is the first report of this association in Taiwan. Pediatricians evaluating children with varicella must be mindful of the potential for Group A beta-hemolytic streptococcal infection.

Comparison of neuromuscular action of rocuronium, a new steroidal non-depolarizing agent, with vecuronium

BACKGROUND

Rocuronium is a new nondepolarizing muscle relaxant. It features a rapid onset and lack of histamine release: It has an intermediate onset of action as vecuronium. The purpose of this study was to compare the neuromuscular action and condition of intubation after a bolus dose of rocuronium or vecuronium (2 x ED90). We also compared the duration of relaxation after intubation and maintenance doses of each drug.

METHODS

Sixty male or female patients, age 18-65, scheduled for elective surgery under general anesthesia were divided randomly into two groups (rocuronium and vecuronium group). All patients were ASA class I-II and pre-operative laboratory data were normal. Anesthesia was performed with fentanyl, isoflurane and O2. Rocuronium 0.6 mg/kg (2 x ED90) or vecuronium 0.1 mg/kg (2 x ED90) was given during induction of anesthesia. The response of adductor pollicis was measured with acceleromyography. Neuromuscular block was maintained by bolus injection of rocuronium 0.15 mg/kg or vecuronium 0.025 mg/kg when T1 reached 25% of control. Onset time, duration, recovery indices, intubation condition and T4/T1 ratio to 70% were recorded. Side effects were recorded during the study.

RESULTS

The onset time was significantly longer in vecuronium group than that of rocuronium group (102.8 +/- 26.9 s vs. 54.9 +/- 10.9 s, p < 0.05). The clinical durations of action were respectively 44.2 +/- 13.2 min in rocuronium group and 42.5 +/- 9.1 min in vecuronium group (T1 to 25%). The duration of the maintenance were respectively 28.8 +/- 9.5 min in rocuronium group and 26.1 +/- 6.8 min in vecuronium group (T1 to 25%). No adverse effect occurred with either drug. The intubation condition was similar in both groups.

CONCLUSIONS

We conclude that rocuronium provides a more rapid onset of action than that of vecuronium. Rocuronium is an intermediate-acting muscle relaxant as vecuronium with good to excellent intubation condition. It may be an useful alternative to vecuronium for rapid tracheal intubation.

Intravenous infusion of low dose propofol for conscious sedation in cesarean section before spinal anesthesia

BACKGROUND

Conscious sedation, not affecting the safety of both mother and fetus, is especially favorable in anxious patients undergoing Cesarean delivery. However, when sedation is started before performing intrathecal anesthesia, the infusion time before delivery will be prolonged. In this study, the incidence of maternal and fetal complications under propofol infusion were evaluated as well as the blood concentrations of propofol during delivery at different time of sedation.

METHODS

Maternal and fetal effects of pre-spinal sedation with low dose propofol infusion technique (3 mg/mg/h following 0.3 mg/kg bolus) in 37 Cesarean parturients were evaluated, compared with another 33 parturients under spinal anesthesia without any sedatives.

RESULTS

The induction to delivery time was 32.6 +/- 7.7 min. Satisfactory, airway-maintaining conscious sedation was shown without increasing the incidence of post-spinal hypotension and hypoxemia compared with non-sedative group. The plasma propofol concentrations in the mean time of delivery in maternal vein and umbilical vein were 0.86 +/- 0.29 and 0.33 +/- 0.11 microgram/ml, respectively. Umbilical venous concentration neither correlated with infusion time nor exceeded the maternal venous concentration. The 1-min and 5-min Apgar scores as well as umbilical venous blood gas analyses did not differ significantly between two groups.

CONCLUSIONS

Conscious sedation by low dose propofol infusion is safe for both mother and fetus in spite of longer infusion time.

Comparison of the genetic knowledge among nurses, students, and general public after ten years of implementation of genetic health program in Taiwan

This study aims to explore the genetic knowledge of different health professional, and non-professional populations after ten years of implementation of genetic health program in Taiwan. A self-administered questionnaire was developed to test the genetic knowledge of 885 respondent who included 361 community health nurses, 74 maternal-child nurses, 364 college students, and 86 members of the general public. The questionnaire included 33 questions which were divided into 4 categories (1) basic genetic knowledge, (2) Mendel's Law and probability, (3) prenatal diagnosis, (4) identification of common genetic disorders. The responses were scored and analyzed statistically with ANOVA tests. Community health nurses had the highest scores of genetic knowledge. However, they need more practice in the application of Mendel's Law and probability. Maternal-child nurses should be involved in genetic education programs and improve their ability to identify common genetic disorders and thus increase their ability to identify cases and provide better information to patients and families. Compared to other groups, college students had lower scores in prenatal diagnosis and identification of common genetic disorders. Therefore, college curricula in genetics need to emphasize more on these subjects. From the study, it was concluded that community health nurses are effective and competent to continue the genetic education as supported by the government in the past ten years. Maternal-child nurses are inevitably involved in genetic service, and they should be provided with suitable continuing education programs. The general public should strengthen their knowledge of prenatal diagnosis and common genetic disorders. Prenatal diagnosis should be added in the school curriculum of college students to expand their knowledge. New genetic technology, such as DNA analysis, should be added in the content of genetic education programs.

Perforin, a cytotoxic molecule which mediates cell necrosis, is not required for the early control of mycobacterial infection in mice

Host defense against mycobacterial infection requires the participation of monocytes and T cells. Both CD4+ and CD8+ T cells have been shown to be important in resistance to mycobacterial infection in vivo. The main contribution of CD4+ T cells to the protective antituberculosis response involves the production of Th1-type cytokines, including interleukin-2 (IL-2) and gamma interferon (IFN-gamma). CD8+ T cells have been considered to be responsible primarily for cytotoxicity mediated by toxic molecules, including perforin. CD8+ T cells may also elaborate Th1-type cytokines, such as IFN-gamma, in response to the infection. To elucidate the contribution of perforin-mediated target cell death to the control of mycobacterial infection in vivo, mice with a disruption in the perforin gene (P-/-) were infected with Mycobacterium bovis BCG or M. tuberculosis Erdman for 5 and 13 weeks, respectively. At 1, 3, 5, and 13 weeks postinfection, the number of viable mycobacteria in the lungs, spleens, and livers of mice were determined by CFU assay. The infected tissues were examined histologically, and cytokine mRNA levels in the spleens of these mice were determined. Similar studies were carried out in Fas receptor-defective (CBA/lpr(cg)) mice to evaluate the contribution of this alternative cytotoxic pathway to the control of mycobacterial infection. The absence of either perforin gene function or Fas receptor gene function did not modify the course of experimental mycobacterial infection in these mice. In addition, both P-/- and Fas receptor-defective mice appeared to have a compensatory activation of cytokine genes, even in the absence of the experimental infection. P-/- mice had a mean 3.4- to 5-fold increase in mRNA levels for IL-10, IL-12p35, IL-6, and IFN-gamma. Similarly, Fas receptor-defective mice had a mean 3- to 3.6-fold increase in mRNA levels for IFN-gamma, IL-12p35, and IL-10. Our results indicate that both perforin-mediated cytotoxicity and Fas-mediated cytotoxicity do not appear to be necessary for the early control of mycobacterial infection in vivo.

The involvement of interleukin (IL)-15 in regulating the differentiation of granulated metrial gland cells in mouse pregnant uterus

Previous studies have suggested that granulated metrial gland (GMG) cells are bone marrow-derived lymphoid cells, which differentiate in situ in the mouse pregnant uterus into natural killer (NK)-like cells. Similar to NK cells, GMG cells express an abundant level of cytolytic mediators such as perforin. The factor(s) regulating the differentiation of GMG cells remain(s) to be identified, although cytokines previously implicated in the stimulation/activation of NK cells (e.g., IL-2, IL-6, IL-7, and IL-12) can be considered as potential candidates. Recently, IL-15, a novel cytokine, which displays biological activities similar to IL-2, has also been shown to be capable of activating NK cells. Using reverse transcription-polymerase chain reaction (RT-PCR) analysis, we have demonstrated in the present study that IL-15 and its cognate receptor, but not the other cytokines, are expressed in the mouse pregnant uterus, with a time course concomitant with those of cytolytic mediators in differentiated GMG cells. Moreover, IL-15, though not IL-2, is capable of inducing the expression of perforin and granzymes in pregnant uterine tissues explanted in vitro. Data obtained from in situ hybridization study have suggested that the macrophages present in the pregnant uterus may be responsible for the production of IL-15. These results suggest that IL-15 is involved in regulating the differentiation of GMG cells during mouse pregnancy.

[Clinical experience of automated double filtration plasmapheresis]

Double filtration plasmapheresis, one kind of fractionation plasmapheresis, was developed from membrane type plasmapheresis to remove only the pathogen and return the normal protein back to the patient. We started our automated double filtration plasmapheresis since December 1993. There were 13 patients who received one hundred treatments totally during one year period. And they are myasthenia gravis (8 patients); acute inflammatory demyelinating polyneuropathy (1 patient), multiple myeloma (1 patient); acquired factor VIII inhibitor (1 patient); autoimmune hemolytic anemia (1 patient); systemic lupus erythematous (1 patient). Technically double filtration plasmapheresis is easy to perform and time-saving. It also makes necessity of replacement fluid less frequent. Incidence of complication is rare, and this includes hypotension 2%, palpitation 1%, headache 1%, hemolysis 4%, air emboli 1%, high secondary pressure 2%, and no motality during our treatment. Clinical response is documented in cases of myasthenia gravis; acute inflammatory demyelinating polyneuropathy and acquired factor VIII inhibitor in our study. In conclusion, double filtration plasmapheresis is a time-saving, convenient, and safe therapeutic modality with rare complication. Because its effectiveness on limited kinds of diseases and costs relatively high price, thus plasmapheresis should be used in selected cases and treat aggressively if indicated.

Interleukin-15 induces the expression of mRNAs of cytolytic mediators and augments cytotoxic activities in primary murine lymphocytes

Interleukin-15 (IL-15) is a novel cytokine displaying biological activities that overlap those of interleukin-2 (IL-2). Like IL-2, IL-15 has been shown to be capable of stimulating the proliferation of human natural killer cells and PHA-treated T lymphocytes and of generating cytotoxic activity in stimulated lymphocyte populations. Using primary murine lymphocytes as a model in the present study, we have investigated the effects of IL-15 on the induction of the expression of mRNAs encoding different lymphocyte cytolytic mediators and the enhancement of cytolytic activities. Using reverse transcription-polymerase chain reaction analysis, both IL-15 and IL-2 have been shown to induce the expression of mRNAs for perforin, granzymes A and B, interferon-gamma, and Fas ligand in primary murine splenic lymphocytes. The induction effect of IL-15 has been shown to be at least partially independent of cell proliferation. Although IL-15 and IL-2 appear to be comparably effective in inducing the expression of cytolytic mediator mRNAs, the former is less potent in eliciting functional cytolytic activity in stimulated lymphocyte populations. The inadequate cytolytic activity of IL-15-stimulated lymphocytes may in part be due to the less efficient production of cytolytic mediator proteins, e.g., perforin and granzyme A, in these cells.