Cytosolic-free calcium elevation in Trypanosoma cruzi is required for cell invasion

To replicate, the trypomastigote form of Trypanosoma cruzi must invade host cells. Since a role for Ca2+ in the process of cell invasion by several intracellular parasites has been postulated, changes in the intracellular Ca2+ concentration in T. cruzi trypomastigotes and in tissue culture L6E9 myoblasts during their interaction were studied at the single cell level using digital imaging fluorescence microscopy or in cell suspensions by fluorescence spectrophotometry. An increase in cytosolic Ca2+ in T. cruzi trypomastigotes was detected at the single cell level after association of the parasites with the myoblasts. Ca2+ mobilization in the host cells was also detected upon contact with trypomastigotes either at the single cell level or in cells grown in coverslips and exposed to suspensions of trypomastigotes. Pretreatment of the parasites with the Ca2+ chelators quin 2 (50 microM) or bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA, 50 microM) decreased the trypomastigotes' association to myoblasts by approximately 40 and 63%, respectively, thus indicating that an increase in intracellular Ca2+ concentration in the parasites is required for cell invasion in addition to Ca2+ mobilization in the host cells.

[Laparoscopic cholecystectomy makes difficult the analysis of gallbladder mucosa. Morphometric study]

Laparoscopic gallbladder surgery damages gallbladder mucosa, impeding an adequate histological examination. We studied gallbladder samples coming from 56 conventional and 44 laparoscopic cholecystectomies performed in patients with chronic cholecystitis without signs of acute inflammation. The length of each examined sample and the length of the portion where superficial epithelia was not found was measured. No differences in sample length was found between both types of cholecystectomy. However; the segment with superficial mucosa was significantly shorter in the samples coming from laparoscopic surgery. Seventeen samples did not contain mucosa at all and 14 of these (82%) came from laparoscopic procedures. Eighty six percent of samples coming from laparoscopic surgery were considered inadequate for histological study compared to 36% of samples coming from conventional cholecystectomy. It is concluded that laparoscopic cholecystectomy hampers the study of gallbladder mucosa and may have an impact on the diagnosis of neoplastic gallbladder lesions.

[Laparoscopic cholecystectomy. 1203 cases with ultraselective cholangiography]

We present our experience at the University of Chile Hospital with 1203 cases of laparoscopic cholecistectomy between April 1991 and July 1993. In only 36 patients ultraselective cholangiography was performed. In 88 cases an endoscopic cholangiography was performed prior to surgery because of suspicion of choledocolithiasis. In 31 of them choledocolithiasis was demonstrated, and was successfully treated by papilotomy in 30 of them. In 5.8% of cases coversion to open surgery was necessary: 1.4% in chronic cholecystitis, 13% in acute cholecystitis and 39% in cases with fibrosis and esclerosis of gallbladder with or without biliary digestive fistula. The intraoperative cholangiography has been advocated as a manner to prevent the common duct injury. In spite of the small number of cases operated on with cholangiography, we haven't seen serious injuries of biliary tract; a carefully disection, as far away as possible of the common duct, is the best way to prevent iatrogenic lesions. Postoperative morbidity was present in 15 cases, 8 of them required a new operation. Two patients died.

Fecal shedding of Clostridium difficile in dogs: a period prevalence survey in a veterinary medical teaching hospital

The goal of this study was to determine the fecal prevalence of Clostridium difficile in dogs who were patients at a veterinary medical teaching hospital. Stool specimens collected from 152 dogs (in- and outpatients) were analyzed for the presence of C. difficile. An additional 42 stool specimens were collected and examined from dogs recently housed at local animal shelters. Following culture on selective medium, C. difficile was identified by a latex agglutination test, and the presence of the toxin A and B genes was determined individually by polymerase chain reaction. Clostridium difficile was isolated from the feces of 28 of the veterinary hospital patients (18.4%); isolates from 14 of these patients (50.0%) were toxigenic. Diarrhea was a clinical finding in 5 (35.7%) of the dogs carrying toxigenic isolates of C. difficile, whereas diarrhea was noted in only 2 of 14 dogs (14.3%) shedding nontoxigenic isolates. Three of 14 dogs (21.4%) shedding toxigenic isolates of C. difficile were receiving antibiotics at the time of stool collection, whereas 5 of 14 dogs (37.5%) shedding nontoxigenic strains of C. difficile were receiving antibiotics. The carriage rate of C. difficile was significantly higher for animals categorized as inpatients of the veterinary hospital. The carriage rate also provided evidence for an increased risk for fecal shedding with increasing age. Clostridium difficile was not isolated from any of the 42 dogs recently housed at local animal shelters. This study confirms the presence of toxigenic C. difficile in dogs at a veterinary teaching hospital.(ABSTRACT TRUNCATED AT 250 WORDS)

Endoscopic bile duct stone removal prior to laparoscopic cholecystectomy

Of 1049 patients referred for laparoscopic cholecystectomy (LC) for symptomatic gallstone disease, 67 (6%) had clinical, biochemical, or echographic findings suggesting common bile duct stones. Patients in this group were studied preoperatively with endoscopic retrograde cholangiopancreatography (ERCP). In 26 patients (39%), the diagnosis was confirmed. In 12 other cases (18%), the macroscopic finding of a stripped or bleeding papilla without common bile duct stones suggested stone migration. ERCP in the remaining 29 patients (43%) was normal. Thirty-four endoscopic sphincterotomies (ES) were performed, 26 for common bile duct stones and 8 for cystic lithiasis or gallbladder microlithiasis. In the entire group of patients with choledocholithiasis, stone removal was possible. All 67 patients underwent laparoscopic cholecystectomy on an average of 2.8 days following the endoscopic procedure. Twenty-one patients (31%) had acute cholecystitis, and 5 had chronic scleroatrophic cholecystitis. Five (7.5%) of the 67 patients were converted to an open procedure. In 10 cases (16%), the cystic diameter was larger than an 8-mm M-L clip, which made necessary the use of endoligature or extra clips. No complications or deaths resulted from ERCP or ES. Two of the 62 patients (3.2%) who underwent LC had to be reoperated on, 1 because of a right subphrenic collection, and the other because of bilious ascites. No common bile duct lesions or deaths resulted in the analyzed group. The average hospitalization time, with the exception of those patients converted or reoperated on, was 8 days.

[Oculomotor paralysis. The perspective of a neuro-ophthalmology consultation]

Ocular paresis is a usual diagnosis in neuro-ophthalmologic consultation, and its aetiology is indeed a challenge. The authors studied 3400 records concerning this consultation, between 1982 and the third quarter of 1993. During this period 221 cases with ocular paresis were selected. During this retrospective study we point out the following items: the cranial nerve affected; the neuro-ophthalmologic semiology; the aetiology and clinical evolution, according to the age groups. From 221 cases selected, 111 were paresis from the VIth pair (50.2%), 88 from the IIIrd pair (39.8%), 14 multiple paresis (6.4%) and 8 paresis from the IVth pair (3.6%). The most frequent complaint was diplopia (> 90%). As far as the aetiological diagnosis is concerned, this was easier to establish in patients > 50 years of age. In this age group the most usual aetiology was vascular and traumatic pathologies. In younger patients the most frequent pathologies were traumatic and tumoral. The prognostic was better in the vascular group, the paresis recovery being > 50% in all other pathologies, except the tumoral one.

Genotyping of Clostridium difficile isolates

Arbitrarily primed polymerase chain reaction (AP-PCR) was used to genotype Clostridium difficile isolates from various sources. Four major molecular types were identified among strains from the American Type Culture Collection previously typed by serogroup and from isolates from patients at the University of California, Davis Medical Center, from a patient at a Utah institution, and from the environment. These groups contained subgroups that displayed, in addition to the common group bands, at least one unique band. Two strains isolated from patients at our institution had the same DNA banding patterns. These patients were hospitalized during the same period, raising the possibility of cross-infection through hospital contact or another common source. These results suggest that this AP-PCR approach will be useful in epidemiologic studies of C. difficile infections.

Health care professional workstation: software system construction using DSSA scenario-based engineering process

This paper describes a new method for the evolutionary determination of user requirements and system specifications called scenario-based engineering process (SEP). Health care professional workstations are critical components of large scale health care system architectures. We suggest that domain-specific software architectures (DSSAs) be used to specify standard interfaces and protocols for reusable software components throughout those architectures, including workstations. We encourage the use of engineering principles and abstraction mechanisms. Engineering principles are flexible guidelines, adaptable to particular situations. Abstraction mechanisms are simplifications for management of complexity. We recommend object-oriented design principles, graphical structural specifications, and formal components' behavioral specifications. We give an ambulatory care scenario and associated models to demonstrate SEP. The scenario uses health care terminology and gives patients' and health care providers' system views. Our goal is to have a threefold benefit. (i) Scenario view abstractions provide consistent interdisciplinary communications. (ii) Hierarchical object-oriented structures provide useful abstractions for reuse, understandability, and long term evolution. (iii) SEP and health care DSSA integration into computer aided software engineering (CASE) environments. These environments should support rapid construction and certification of individualized systems, from reuse libraries.

EEG coherences in patients with brain lesions

EEG coherence between all pairwise combinations of the 10/20 system was studied in two groups: control subjects and patients with space-occupying brain lesions. Coherence was separately computed for the delta, theta, alpha and beta bands. Comparisons between both groups showed highly significant differences in all bands. In the patients with lower coherence values, these differences were mainly in the alpha band. When intra-hemispheric coherences between controls and patients with left hemispheric lesions were compared, significant differences were observed only in the left hemisphere. Comparisons between controls and patients with lesions in the right hemisphere also showed significant differences only in the injured hemisphere. In patients, paired t tests between the values of the intra-hemispheric coherence in the left hemisphere and the corresponding values in the right hemisphere demonstrated that lower coherences were confined to the damaged hemisphere. Our conclusion is that in the presence of lesions disrupting cortex and adjacent white matter the coherence between this area and the remaining cortical areas is lower than normal due to impairment of the fibers that connect the damaged area with the rest of the brain.

Correlation between computed tomography and voltage and current source density spectral EEG parameters in patients with brain lesions

In a group of patients with space-occupying brain lesions, CT measurements were correlated with absolute power (AP) and relative power (RP) of the delta, theta, alpha and beta EEG bands, calculated from the raw EEG potentials (EEGp) and from the Laplacian estimates also called "current source densities" (CSD). Rank correlations were calculated between the number of abnormal values in each band and the following CT measures: volume of the lesion and of the edema, density of the edema, percentage of ventricular collapse and midline shift. Abnormal spectral values are those which are significantly higher than the norm for the same age, in the delta and theta bands, and significantly lower in the alpha and beta bands. Spectral parameters obtained from the CSD showed higher correlations with CT measures than those calculated from the EEGp. In the Laplacian, all CT measures had a significant correlation with delta AP. Theta AP was significantly correlated with the volume and density of the edema, as well as with midline shift. Significant correlations were also observed with delta and alpha RP. However, changes in RP were considered to be a consequence of the increase in delta AP. Canonical correlation analyses between AP and RP calculated from EEGp or CSD and the first 3 CT measures showed that the volume of the lesion was only correlated with delta AP and RP. The volume and density of the edema showed a significant correlation with delta, theta and alpha AP calculated from EEGp and only with theta and alpha AP in the Laplacian. Since the EEGp tends to produce a more extensive and diffuse picture of abnormality, whereas the Laplacian acts as a spatial filter emphasizing local sources over distant sources, we concluded that edema is related not to delta activity, but to the theta and alpha power.

Mollaret's meningitis associated with herpes simplex type 2 infection

We describe three patients with benign recurrent aseptic meningitis (Mollaret's meningitis). For one of these cases, the episodes of meningitis were associated with herpetic outbreaks. Mollaret cells, which are a hallmark of Mollaret's meningitis, were present in the CSF from two of the three patients. In all cases, herpes simplex virus type 2 DNA was present in the CSF during the acute illness as detected by polymerase chain reaction amplification, although viral cultures from CSF were all negative. Herpesviruses, notorious for frequent and sporadic recurrence, are ideal candidates for the cause of Mollaret's meningitis.

[Transferrable broad-spectrum beta-lactam resistance in Klebsiella pneumoniae R-3455]

Bacterial resistance to antimicrobial agents is a common problem observed in hospitals. We characterized a clinical isolate of Klebsiella pneumoniae (R-3455) which was resistant to high concentrations of broad spectrum beta-lactams, aminoglycosides, fluoroquinolones, chloramphenicol and tetracycline. Conjugation experiments showed that the multiresistance could be transferred to Escherichia coli J53-2 receptor strain. The transconjugant X-3455 was resistant to all antibacterials assayed in R-3455, except to fluoroquinolones. We found that both strains R-3455 and X-3455 produced a beta-lactamase which was sensitive to clavulanic acid. Southern hybridization and PCR analysis showed the presence of at least, a TEM type beta-lactamase gene in both strains.

BCG vaccination protects against leprosy in Venezuela: a case-control study

A total of 64,570 household and other close contacts of about 2000 leprosy cases were screened for eligibility for entry into a trial of a new leprosy vaccine. The screening procedure included a clinical examination for leprosy and for the presence of BCG and lepromin scars. Ninety-five new cases of leprosy were identified, and the prevalence of BCG and lepromin scars among them was compared with similar data from matched controls selected from among those with no evidence of leprosy. The difference in the prevalence of BCG scars in the two groups was used to estimate the protection against leprosy conferred by BCG vaccination. One or more BCG scars was associated with a protective efficacy of 56% (95% confidence limits 27% to 74%). There was a trend of increasing protection with four or more BCG scars, but this was not statistically significant. There was no evidence that the efficacy of BCG varied with age or according to whether or not the contact lived in the same household as a case. The protective effect was significantly higher among males, and was significantly greater for multibacillary than for paucibacillary leprosy.

Diagnosis and monitoring of Clostridium difficile infections with the polymerase chain reaction

Toxigenic Clostridium difficile is the etiologic agent of pseudomembranous colitis. We have developed an assay system for the rapid direct detection of toxigenic C. difficile in human stool samples. After DNA extraction, polymerase chain reaction (PCR) amplification is undertaken with primers targeting specific sequences in the C. difficile 16S rRNA gene. Next, toxigenic strains of C. difficile are distinguished from nontoxigenic strains by PCR amplification of toxin A and/or B gene sequences. This study included 12 patients with C. difficile colitis, seven of whom had clinical relapses after discontinuation of vancomycin therapy. We detected toxigenic C. difficile in stools from four (57%) of these seven patients before relapse--at a time when no toxin B was detectable in stools and results of anaerobic culture were negative. The PCR assay is 100-fold more sensitive than anaerobic culture methods. The course of the infection in one patient (both during and after therapy) was monitored by the PCR technique. The multigene analysis approach permitted the detection of colonization with a nontoxigenic strain when this patient's relapses had cleared. This clinically applicable assay allows earlier detection of infection with toxigenic C. difficile. The result is more timely therapeutic intervention.

[Percutaneous valvuloplasty in congenital aortic valve stenosis]

PURPOSE

To show the initial experience of Institute of Cardiology of Rio Grande do Sul in the treatment of congenital valvular aortic stenosis with percutaneous balloon aortic valvuloplasty.

METHODS

Twenty four patients were submitted to the procedure, 14 males and 10 females. The mean age 7 years (4 days-17 years). Four patients were aged below 30 days and three patients had previous surgical valvuloplasty. The percutaneous balloon aortic valvuloplasty were made the retrograde approach in all patients.

RESULTS

The peak systolic pressure gradient was reduced from 65.96 +/- 22.68 to 27.08 +/- 18.74 mmHg. The procedure resulted in aortic regurgitation in seven patients and worsened aortic regurgitation in two patients. One patient had cardiac arrest that was reverted by cardiopulmonary resuscitation, this patient had hospital discharge without sequel. Five patients had acute femoral artery thrombosis, and hemorrhage in the site of puncture happened in one patient.

CONCLUSION

The percutaneous balloon aortic valvuloplasty results in effective reduction of the peak systolic pressure gradient, it is a save and effective therapy in patients with congenital valvular aortic stenosis. Further evaluation of the long term results are necessary for definitive conclusions.

Specific detection of toxigenic strains of Clostridium difficile in stool specimens

Clostridium difficile is the infectious agent responsible for antibiotic-associated colitis. We report the use of the polymerase chain reaction technique to identify toxigenic strains of C. difficile in human stool specimens. A set of primers based on the nucleotide sequence of the toxin B gene, which amplified a 399-bp fragment from isolates producing toxin B, was designed. We examined 28 known toxigenic strains, which were all positive by this assay. DNAs from the nontoxigenic strains examined and from strains of Clostridium sordellii and C. bifermentans were not amplified with these primers. The sensitivity of this assay allowed us to identify as little as 10% toxigenic C. difficile cells in the presence of 90% nontoxigenic cells and to detect the toxin B gene in 1 pg of DNA from a toxigenic strain. DNAs extracted from 18 clinical stool specimens that were positive for toxin B by the tissue culture cytotoxicity assay were also positive by this assay. In addition, we detected toxin B sequences in DNA from 2 of 18 stool specimens that were negative for toxin B by the cytotoxicity assay. These two stool specimens were from patients who had a clinical pattern of colitis that was compatible with C. difficile causation. This rapid, sensitive assay will be useful for specific identification of toxigenic C. difficile and for revealing cases that are undetected by analysis of fecal samples for toxin B alone.

[Mucinous adenocarcinoma of the urachus. Apropos of a case]

This report present one case of mucinous adenocarcinoma of the urachus, a very uncommon tumour with eccentric clinical behaviour. It includes a brief description of both its macro and microscopic appearance, establishing the differential diagnosis both with adenocarcinoma of the vesical dome and the metastatic tumours which can affect the bladder. Also, there is a brief comment on the main anatomo-clinical characteristics of these tumours.

Triage of patients out of the emergency department: three-year experience

Because of severe emergency department (ED) overcrowding, the authors initiated a program of referring certain patients who were assessed as not needing emergency care away from the ED. A selected group of patients who presented to a busy university ED were refused treatment and triaged away following a medical screening examination performed by a nurse. In this 3-year study 136,794 patients presented to the triage area in the ED, of which 21,069 (15%) were refused care and referred elsewhere. Letters and calls to all referral clinics, eight local EDs, and the coroner's office identified no patients who had been grossly mistriaged, and only insignificant adverse outcomes could be identified. Additional follow-up on 3,740 individuals triaged away was performed by telephone. Responses from this survey indicated that 42% of persons received care elsewhere the same day, 37% within 2 days, and 22% decided not to seek medical care. A group of 1.6% sought care at other hospital EDs for minor complaints. The authors concluded that a group of patients can be selectively triaged out of the ED without significant adverse outcomes, which may offer one approach to the problem of ED overcrowding.

Immunoprophylactic trial with combined Mycobacterium leprae/BCG vaccine against leprosy: preliminary results

In an attempt to find a vaccine that gives greater and more consistent protection against leprosy than BCG vaccine, we compared BCG with and without killed Mycobacterium leprae in Venezuela. Close contacts of prevalent leprosy cases were selected as the trial population since they are at greatest risk of leprosy. Since 1983, 29,113 contacts have been randomly allocated vaccination with BCG alone or BCG plus 6 x 10(8) irradiated, autoclaved M leprae purified from the tissues of infected armadillos. We excluded contacts with signs of leprosy at screening and a proportion of those whose skin-test responses to M leprae soluble antigen (MLSA) were 10 mm or more (positive reactions). By July, 1991, 59 postvaccination cases of leprosy had been confirmed in 150,026 person-years of follow-up through annual clinical examinations of the trial population (31 BCG, 28 BCG/M leprae). In the subgroup for which we thought an effect of vaccination was most likely (onset more than a year after vaccination, negative MLSA skin-test response before vaccination), leprosy developed in 11 BCG recipients and 9 BCG/M leprae recipients; there were 18% fewer cases (upper 95% confidence limit [CL] 70%) in the BCG/M leprae than in the BCG alone group. For all cases with onset more than a year after vaccination irrespective of MLSA reaction the relative efficacy was 0% (upper 95% CL 54%; 15 cases in each vaccine group). Retrospective analysis of data on the number of BCG scars found on each contact screened suggested that BCG alone confers substantial protection against leprosy (vaccine efficacy 56%, 95% CL 27-74%) and there was a suggestion that several doses of BCG offered additional protection. There is no evidence in the first 5 years of follow-up of this trial that BCG plus M leprae offers substantially better protection against leprosy than does BCG alone, but the confidence interval on the relative efficacy estimate is wide.

Use of the polymerase chain reaction for the specific and direct detection of Clostridium difficile in human feces

The polymerase chain reaction was used for the detection of Clostridium difficile, the etiologic agent of antibiotic-associated colitis. An upstream primer identical to a coding region (segment I) of the C. difficile 16S rRNA gene and a downstream primer complementary to a highly conserved region of eubacterial 16S rRNA served to amplify a targeted 270-base-pair fragment of genomic DNA. This technique allowed the detection of as few as 10 C. difficile organisms among 10(6) Escherichia coli bacteria. This level of sensitivity represents a 100-fold increase over that of conventional anaerobic culture. C. difficile was detected in DNA extracted directly from the stools of 23 patients with antibiotic-associated colitis and from those of four patients with diarrhea whose stools had been negative for C. difficile when assessed in a cytotoxicity assay. No amplification products were found in the stools of asymptomatic patients. When detected in stools of symptomatic patients, amplification products of C. difficile were confirmed by Southern blotting with a nonradioactive, horseradish peroxidase-catalyzed, chemiluminescent probing system in which biotin-labeled oligonucleotides were used. This system discriminates between C. difficile and similar organisms, such as Clostridium sordellii and Clostridium bifermentans. The combination of the polymerase chain reaction with enzyme-linked probing results in a faster and more sensitive assay for C. difficile than standard culture.

Birth of the first 100 babies in Hawaii after conception in-vitro: experience at the Pacific In-Vitro Fertilization Institute

This paper reports on the first 100 infants delivered consecutively the result of 63 pregnancies after conception in-vitro at the Pacific In-Vitro Fertilization (IVF) Institute. These pregnancies were established prior to the introduction of embryo-cryopreservation into the program. Ninety-seven percent (97%) of singleton pregnancies delivered after 36 weeks; only 5/31 (16%) required tocolytic therapy. The overall multiple gestation rate was 51%, higher than in many other IVF centers. Maternal complications and neonatal morbidity were associated primarily with these multiple gestations. Forty-one percent (41%) delivered in less than 36 weeks, and tocolytics were administered in 22/27 (81%) of twin and 5/5 (100%) of triplet gestations. Neonatal morbidity was noted in 39 infants (33 from multiple gestations); 28 neonates were admitted to the intensive care unit (27 from multiple gestations). Nine births had or developed minor abnormalities (hernias, pyloric stenosis). One case of Trisomy 21, and one infant death at 11 months occurred in the group. The caesarean section rate for all IVF deliveries was 65%. It is concluded that IVF is clearly established in Hawaii for infertility refractory to other methods of treatment. The risk associated with IVF stem from the possibility of multiple gestations, not whether the pregnancy was initiated in-vitro. In the future, embryo cryopreservation may help to reduce the risk of multiple pregnancy.

Relapsing polychondritis and Reiter's syndrome

We describe a case of relapsing polychondritis associated with Reiter's Syndrome in a 46-year-old white man. Relapsing polychondritis is a rare disorder of unknown etiology associated in about 30% of cases with other rheumatic disorders such as connective tissue diseases, vasculitis and exceptionally, seronegative spondyloarthritis. We found this association only once in our review of the literature.

Fatal varicella in an adult: case report and review of the gastrointestinal complications of chickenpox

An unusual and fatal case of primary varicella in an adult is presented. Involvement of the small intestine first manifested as abdominal pain and later progressed to gastrointestinal bleeding with subsequent dissemination of the infection. Although it has previously been speculated that gastrointestinal bleeding can result from infection with the varicella-zoster virus, the data from this case include histologic and cultural evidence that supports the clinical observations. The literature has been reviewed, and the management of this patient has been critically evaluated.

A University of California State-supported AIDS research award program--a unique state and university partnership in AIDS research

This article describes the State-supported University of California AIDS research award program and its major accomplishments. It shows how a partnership between a University and a State resulted in the formation of a successful, efficient, and cost-effective AIDS research award program. This program provides funds for rapid testing of investigator-initiated meritorious research ideas, new drugs, and treatment modalities. Funds were also utilized to establish three AIDS Clinical Research Centers, which evolved into regional consortia that coordinate trials of new drugs and other modalities. This program succeeded in involving investigators whose efforts have led to excellent medical care, advanced technologies, and new drugs for treating AIDS and AIDS-related diseases. The University remains committed to continuing support of all areas of AIDS research, emphasizing drug and vaccine development, pediatric AIDS, and AIDS prevention studies in groups at high risk for HIV infection.

Depression of cell-mediated immunity in plasmacytoma-bearing mice

Previous reports have documented that mice bearing plasmacytomas (PC) are suppressed in their ability to mount a primary antibody response, whereas cellular immunity appears to be normal. Studies presented here provide evidence that T cell responsiveness is also depressed in BALB/c mice bearing the Lieberman plasmacytoma (Lpc-1). For instance, splenocytes from mice bearing large tumours were impaired in their in vitro ability to respond to the T cell mitogen, mount an appropriate alloreactive cytolytic T lymphocyte response, and produce interleukin-2 (IL-2). A population of suppressor cells was detected in the spleens 7 days after tumour implantation as evidenced by their ability to prevent normal splenocytes not only from responding to antigens in mixed lymphocyte culture, but also from producing IL-2. A similar inhibitory effect was observed with culture supernatants of these cells, indicating the existence of a soluble suppressive factor. Therefore, the present study demonstrates that cellular immune responses are impaired in mice bearing Lpc-1 tumours and that this effect may be due to the generation of suppressor cells and/or a suppressive factor.

The mechanism of action of a synthetic immunomodulator, 3,6-bis(2-piperidinoethoxy)acridine trihydrochloride (CL 246,738), in natural killer cell activation in animals

CL 246,738 is a low molecular weight, synthetic immunomodulator. The present study was done to determine the interaction among interferon (IFN), macrophages, and natural killer (NK) cells in mice following oral administration of CL 246,738. Splenic NK activity as evidenced by lysis of YAC-1 lymphoma cells in vitro was found to be augmented by the compound not only in normal mice, but also in immunodeficient beige and nude mice. Lytic activity remained elevated from one to seven days after a single treatment and the peak activation varied depending on the source of NK cells. NK cell activity associated with the peritoneal exudate cell population peaked at day 1 and returned to normal by day 2, whereas NK cell activity of peripheral blood lymphocytes peaked at day 3 and remained significantly elevated until day 7. Liver associated NK activity peaked at day 4 and remained significantly elevated at day 7 after treatment with CL 246,738. Lung associated NK activity was elevated by day 1 after treatment, peaked at day 4 and returned to normal by day 7 after drug administration. The drug was also effective in inducing IFN in all mouse strains tested. When these drug-treated mice were given antibody to IFN-(alpha + beta) but not to IFN-(beta), both IFN levels and NK cell activity decreased, suggesting the importance of IFN-(alpha) in this system. Furthermore, mice that had received carrageenan prior to, but not after CL 246,738 administration showed reduced serum IFN titers as well as decreased NK cell activity, indicating that macrophages played an intermediate role in immune enhancement by the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Health status of Air Force veterans occupationally exposed to herbicides in Vietnam. I. Physical health

The Air Force Health Study is a 20-year comprehensive assessment of the health of Air Force veterans of Operation Ranch Hand, the unit responsible for aerial spraying of herbicides in Vietnam. The study compares the health and noncombat mortality of Ranch Hand veterans with a comparison group of Air Force veterans primarily involved with cargo missions in Southeast Asia but who were not exposed to herbicides. This report summarizes the health of these veterans as determined at the third in a series of physical examinations. Nine hundred ninety-five Ranch Hands and 1299 comparison subjects attended the second follow-up examination in 1987. The two groups were similar in reported health problems, diagnosed skin conditions, and hepatic, cardiovascular, and immune profiles. Ranch Hands have experienced significantly more basal cell carcinomas than comparison subjects. The two groups were not different with respect to melanoma and systemic cancer.

Toxicity of nitrobenzene compounds towards isolated hepatocytes: dependence on reduction potential

1. The cytotoxicity of p-substituted nitrobenzenes towards isolated hepatocytes under aerobic or hypoxic conditions has been determined. The nitrobenzene concentration required to cause 50% cytoxicity in 2 h was a function of the one-electron reduction potential of the nitrobenzene, with the more cytotoxic compounds having the strongest electron-withdrawing substituents. 2. The effectiveness of the nitrobenzenes at causing cytotoxicity under aerobic but not hypoxic conditions was markedly increased if hepatocyte catalase was inhibited with azide. 3. Nitrobenzenes at cytotoxic concentrations induced cyanide-resistant respiration in isolated hepatocytes. Their effectiveness correlated with their cytotoxicity. 4. The rate of oxygen activation of these nitrobenzenes by ascorbate was also a function of the one-electron reduction potential. The nitro compounds with the strongest electron-withdrawing substituents were the most rapidly reduced. 5. Most nitrobenzenes were more cytotoxic under aerobic than hypoxic conditions. Ascorbate enhanced hypoxic, but not aerobic, cytotoxicity. 6. It was concluded that the cytotoxicity of different nitrobenzenes is related to their ease of reduction to nitro radical anions and nitrosobenzenes. Aerobic cytotoxicity is probably initiated by redox cycling and oxygen activation by the nitro radical anions whereas hypoxic cytotoxicity is probably initiated by the alkylation of macromolecules by nitrosobenzene metabolites.

[Rhythm profile in patients with psoriatic arthritis]

OBJECTIVE

To analyze the rhythmic profile in patients with psoriatic arthritis (PA).

DESIGN

In order to evaluate the rhythmic profile of patients with PA, we have carried out ambulatory 24 hour ECG recordings in 22 patients presented consecutively to the Holter ECG laboratory.

SETTING

Patients followed in a specialised rheumatology consultation, in Santa Maria Hospital.

PATIENTS

We have studied 22 patients (pts), 10 male and 12 female, aged 49.8 +/- 8.4 years, presenting PA diagnosed in average 12.9 years before. A group of 36 individuals, 25 male and 11 female, aged 37 +/- 8 years and without disease, were used as control.

RESULTS

All patients were in sinus rhythm with a mean heart rate of 71 +/- 6 (min - 51.5 +/- 7.0 and max - 130.3 +/- 15.0). In 8 (36.6%) there were sinus bradycardia less than 50/min and sinus tachycardia (greater than 120/min) in 15 patients (68.1%). Two patients (9%) presented supraventricular tachycardia and one had AV block. There were premature atrial systoles in 14 pts (63.6%), and ventricular arrhythmias in 9 (40.9%). In control group, there were sinus bradycardia in 16.6%, sinus tachycardia in 33.3%, premature atrial systoles in 33.3% and ventricular arrhythmias in 25% of them; in 11% there were conduction disturbances.

CONCLUSIONS

a) Premature atrial systoles were the rhythm disturbance more prevalent. b) Patients with PA presented a significant higher incidence of sinus bradycardia and sinus tachycardia. c) Cardiac conduction disturbances were not frequent. d) Our results may suggest the presence of a subtle autonomic dysfunction in patients with psoriatic arthritis.

Update on pseudomembranous colitis

These discussions are selected from the weekly staff conferences in the Department of Medicine, University of California, San Francisco. Taken from transcriptions, they are prepared by Homer A. Boushey, MD, Professor of Medicine, under the direction of Lloyd H. Smith, Jr, MD, Professor of Medicine and Associate Dean in the School of Medicine. Requests for reprints should be sent to the Department of Medicine, University of California, San Francisco, School of Medicine, San Francisco, CA 94143.

Clostridium difficile in the intensive care unit: management problems and prevention issues

Several patients hospitalized in our 12-bed medical ICU were found to have Clostridium difficile associated colitis. Stool cultures of all patients identified eight cases (three culture positive, and five culture and cytotoxin positive), seven of which were geographically and temporarily clustered within a 2-wk period. At least one patient appeared to contract the disease after hospitalization and in the absence of antibiotic therapy or other known major risk factors. The outbreak highlights the problem of C. difficile in the ICU. We believe that a heightened awareness of the multiple risk factors and preventive measures, along with consideration of possible nosocomial transmission, will be necessary to prevent or arrest future clusters of cases in the ICU. The diagnosis of one patient with this infection in a unit should prompt a review of all other patients within the unit.

Endocarditis due to Streptococcus faecalis with high-level resistance to gentamicin

Recently, reports of Streptococcus faecalis with resistance to high levels of gentamicin have appeared in the literature, although there have been no previous reports of endocarditis due to such organisms. In this article, two cases of endocarditis--both due to Streptococcus faecalis with high-level gentamicin resistance and both presenting in an atypical manner--are described. The data suggest that a high level of suspicion regarding a diagnosis of endocarditis must be maintained in such cases and that, once a case is diagnosed, careful evaluation in the microbiology laboratory is helpful in determining the optimal antimicrobial regimen.

Pedestrian accidents: adult and pediatric injuries

An epidemologic review of 217 pedestrian injuries treated at a level one trauma center during a one-year period is presented. Injuries that occurred in pediatric age group patients were reviewed separately from adults. In both categories approximately 60% were admitted to the hospital. Hospital length of stay and severity of injuries was found to be much worse in adults. Seven percent of adults and 3% of children died after arrival at the hospital. The most common areas of injury in both groups were the head and the distal extremities. Nearly 25% of adults sustained tibia-fibular fractures. This study shows that the incidence of critical injuries in pedestrians is high, and adults sustain more severe injuries than children. We clarify types of injuries commonly seen in pedestrian trauma.

Reconstitution of cytolytic alloreactivity with N-[4-[(4-fluorophenyl) sulfonyl]phenyl]acetamide (CL 259,763) in animals immunocompromised by cyclophosphamide

A novel synthetic immunopotentiator, i.e. N-[4-[(4-fluorophenyl)sulfonyl]phenyl]acetamide (CL 259,763), was investigated for its potential in reconstituting the cell-mediated immune response of animals whose immunologic system had been severely depressed by cytoreductive agents. It was demonstrated that lymphocytes from mice which had received 300 mg/kg of cyclophosphamide (CY) immediately following antigen sensitization had a reduced capability of responding to alloantigens in mixed lymphocyte culture and failed to generate effective cytolytic T-lymphocytes (CTL) capable of destroying appropriate tumor target cells in a cytotoxicity assay. However, treatment of these immunocompromised animals with CL 259,763 produced a significant restoration of alloreactivity, as evidenced by an enhancement of the CTL response. Although effective doses of CL 259,763 ranged from 20 to 300 mg/kg, the optimal effect was observed at 75 mg/kg. Findings from a time course study indicated that the maximum restoration occurred when CL 259,763 was given to mice 2-5 days after, but not before or simultaneously with, CY treatment. Both the immunoimpairment by CY and its reversal by CL 259,763 appeared not to be antigen specific. The lessened immunoreactivity of CY-treated mice was explicable by the presence of suppressor cells in their spleens. These suppressors were able to adhere to plastic and resisted treatment with anti-Thy 1.2 antibody, indicating a macrophage characteristic. Flow cytometric analysis indicated a quantitative depletion of all T-lymphocytes, including Thy-1.2(+), Lyt-1(+), Lyt-2(+) and L3T4(+) subsets in the spleens of CY-treated mice; however, a population of Mac-1(+) cells was markedly expanded.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of antibiotic-associated Clostridium difficile colitis with oral vancomycin: comparison of two dosage regimens

PURPOSE

High-dose (500 mg orally four times daily) vancomycin is considered by many investigators to be the most effective treatment for antibiotic-associated Clostridium difficile colitis. However, a lower dosage of 125 or 150 mg given three or four times a day has become popular, has been shown to be effective, and is less expensive than the high-dose regimen. We therefore decided to compare two vancomycin dosage regimens in a randomized trial.

PATIENTS AND METHODS

The study involved 46 hospitalized patients with serious underlying diseases complicated by C. difficile diarrhea or colitis. Patients were assigned (according to a table of random numbers) to treatment with either 125 or 500 mg of vancomycin orally four times daily for an average of 10 days.

RESULTS

No significant differences in measurable responses to the two regimens were noted. There were no treatment failures. The mean duration of diarrhea after initiation of therapy was about four days, and almost all patients had no diarrhea after one week. The organism continued to be demonstrated in the stools of about 50 percent of patients for the first few weeks after completion of therapy, and nine (20 percent) patients developed a recurrence of their diarrheal illness. Vancomycin was well tolerated by all patients.

CONCLUSION

Since the dose of 125 mg appeared to be as effective as the 500-mg dose, which is more expensive, the 125-mg dose is preferred when vancomycin is used in treatment of this disease, unless the patient is critically ill.

The metabolism of N-acetyl-3,5-dimethyl-p-benzoquinone imine in isolated hepatocytes involves N-deacetylation

3,5-Dimethyl-N-acetyl-p-benzoquinone imine (3,5-dimethyl-NAPQI) was cytotoxic to isolated hepatocytes from Sprague Dawley rats at levels between 200 and 300 microM. It rapidly oxidized intracellular glutathione within 10 sec, with the formation of oxidized glutathione. The cytotoxicity of 3,5-dimethyl-NAPQI could be prevented over a 3.5-hr period with the carboxylesterase inhibitor bis(p-nitrophenyl) phosphate, indicating that cytotoxicity involved N-deacetylation. The N-deacetylated product could be trapped with glutathione as 3-(glutathion-S-yl)-4-amino-2,6-dimethylphenol in 3,5-dimethyl-NAPQI-treated hepatocytes but not in hepatocytes pretreated with bis(p-nitrophenyl) phosphate, indicating that N-deacetylation activity had been inhibited. 3,5-Dimethyl-NAPQI was readily N-deacetylated by rat liver microsomes, in contrast to 3,5-dimethylacetaminophen. The latter was also not cytotoxic to hepatocytes at up to 2 mM. The N-deacetylated product 4-amino-2,6-dimethylphenol rapidly underwent autoxidation to form 2,6-dimethylbenzoquinone imine and was highly cytotoxic to hepatocytes at 200-300 microM. The latter reacted with glutathione to give the above conjugate and no glutathione oxidation occurred. Dithioerythritol (2 mM) added at 10, 20, and 30 min after 3,5-dimethyl-NAPQI delayed but did not prevent cytotoxicity. Dithioerythritol also resulted in the partial restoration of GSH, presumably as a result of reduction of protein mixed disulphides. The mechanism of cytotoxicity of 3,5-dimethyl-NAPQI therefore appears to be a result of a combination of oxidative stress and deacetylation resulting in arylation.

Restoration of cytolytic T-lymphocyte response with a new immunopotentiator, N-(4-[(4-fluorophenyl)sulfonyl]phenyl)acetamide (CL 259, 763), in mice

The immunorestorative characteristics of a novel synthetic immunomodulator, N-(4-[(4-fluorophenyl)sulfonyl]phenyl)acetamide (CL 259, 763), has been investigated in several experimental models. In one situation, the compound was shown to enhance the induction of a cytolytic T-lymphocyte response to the murine MBL-2 leukemia implanted in its syngeneic host in which only a minimal reactivity to the tumor is normally displayed. In a Vaccinia virus model, the compound similarly augmented the lytic activity of cytolytic T-lymphocyte to virus-infected targets in not only viral antigen-primed but also cyclosporin A-impaired mice. Likewise, the alloreactive cytolytic T-lymphocyte activity was recovered in animals immunocompromised by inoculation with murine plasmacytomas or cytoreductive anticancer drugs, such as cyclophosphamide and 5-fluorouracil. Thus, the present findings suggest that CL 259,763 is effective in potentiating the immune response to weak antigens as well as in restoring alloreactivity by sparing the immunotoxicity associated with the administration of cytotoxic drugs and the growth of neoplasms.

Clostridium difficile as a nosocomial pathogen

Patients admitted to a 19-bed floor with intermediate nursing care were studied for the onset of Clostridium difficile-associated diarrhoea during a six-month period (181 calendar days) in 1986-87. All admitted patients were reviewed weekly and followed after discharge from the study unit to other inpatient services. Multiple items in the environment of five patients' rooms were sampled bacteriologically for the presence of C. difficile weekly during the study period. Three of the rooms were selected for study because of a higher prevalence of C. difficile associated diarrhoea in the prior three years and two were selected because no cases had been discovered previously in these rooms ('control rooms'). Nine of 521 patients admitted to this unit developed C. difficile diarrhoea (1.73 cases/100 patients admitted) versus 0.30/100 patients admitted to all other sites in our hospital (24 of 7970 other patients). This represented respectively 3.91 cases per 1000 patient days on this floor versus 0.37 patients/1000 patient days throughout the hospital. Seven of the C. difficile diarrhoea cases were associated with stay in the C. difficile associated rooms, versus two cases in the two 'control rooms'. C. difficile was isolated from the toilet seats, bedpan hopper, night stands or food trays. Of some 1955 cultures taken, only 1.9% overall were positive for C. difficile.

Pyogenic liver abscess. Diagnostic and therapeutic strategies

A retrospective review of 26 adult patients admitted to University of California, Davis, Medical Center (UCDMC) with pyogenic liver abscess (1980-1986) was performed to ascertain the impact of rapid diagnosis and percutaneous drainage. Ultrasonographic examinations and computed tomography (CT) scans were highly sensitive and noninvasive imaging modalities. Sixteen patients had solitary abscesses and seven had multiple microscopic abscesses. The median time interval from admission to diagnosis and therapy was 2 and 3 days, respectively. Origin of the abscess was determined in 22 patients, the biliary tree being the most common source. Medical therapy was successful in three patients with microabscesses but failed in two. Nine patients had percutaneous drainage; two required repetitive percutaneous catheter placement, and two proceeded to surgical drainage. Twelve patients had surgical drainage; one required repetitive surgical drainage. Postdrainage complications were minimal in all groups. Overall mortality role was 11.5% (two patients). Deaths were related to delay in diagnosis, gram-negative sepsis at presentation, and biliary origin of the abscess.

Effect of hyperthermia on the sensitivity of human colon carcinoma cells to mitoxantrone

The effect of temperature on the cytotoxicity of mitoxantrone (MX) was investigated by exposing human WIDR colon carcinoma cells to elevated temperatures in the presence of drug. The survival of treated cells was determined by their ability to proliferate and to form colonies in vitro. It was demonstrated that incubation of WIDR cells with MX at 42 degrees C produced not only a higher toxicity but also a more rapid action than when cells were exposed to drug at 37 degrees C. By measuring the amounts of 3H-MX incorporated by treated tumor cells, it was shown that cells at 42 degrees C induced an approximately threefold increase in drug uptake when compared to cells at 37 degrees C. The effect seemed long-lasting but preheating did not induce tolerance to a subsequent exposure to MX hyperthermia. Therefore, it is clear that the cytotoxic potency of MX can be augmented by elevated temperature possibly by enhancing the uptake of drug. The present findings may prove useful for designing an effective clinical regimen of MX thermochemotherapy.

Internalization and re-expression of antigens of human melanoma cells following exposure to monoclonal antibody

Modulation of the surface membrane of human Sk-Mel-28 melanoma cells by monoclonal antibody (MoAb) 96.5 recognizing p97 determinants was examined using direct radioimmunoassay and indirect fluorescent antibody-staining techniques. It was determined that the majority of 111In-labeled antibody that remained associated with cells after a 24-hr incubation at 37 degrees C had been internalized because MoAb 96.5 was no longer visible on the cell surface. A second treatment of these cells with the same antibody 24 hr later not only increased the cell-associated radioactivity, reflecting an increase of total antibody bound, but also rendered these cells membrane immunofluorescent again, indicating the re-expression of surface antigens. Autoradiographs of the electrophoretically analyzed membrane components of Sk-Mel-28 cells further demonstrated the appearance of newly synthesized 97-kDa proteins that were immunoprecipitable with MoAb 96.5. Taken together, the present findings suggest that p97 antigens undergo endocytosis in Sk-Mel-28 cells following exposure to MoAb 96.5. However, the same antigens were regenerated and expressed on the cell surface within a period of 24 hr. The re-expression of tumor cell surface antigen following initial internalization of the MoAb-antigen complex may have implications for diagnosis and therapy.

Isolation and partial characterization of 2-microns yeast plasmid as a transcriptionally active minichromosome

Yeast cell extracts from 2-microns-containing strains (cir+) showed higher transcriptional activity than their corresponding isogenic sets (cir0). These extracts were used to purify transcriptionally active 2-microns minichromosomes in a sucrose gradient. Minichromosomes were transcribed in vitro and, employing hybridization techniques, the RNA synthesized was shown to present 2-microns-specific sequences. This model system should permit the direct study of transcriptionally active eucaryotic chromatin.

Therapy of relapsing Clostridium difficile-associated diarrhea and colitis with the combination of vancomycin and rifampin

Seven patients with multiple bacteriologic and symptomatic relapses of Clostridium difficile-associated diarrhea and/or colitis were treated with vancomycin and rifampin in combination. Diarrhea and abdominal pain promptly resolved in all, and neither C. difficile nor its toxin could be recovered from their stools shortly after therapy. However, stools of all patients subsequently became culture-positive for C. difficile and occasionally had demonstrable cytotoxin. Except in one instance following oral antibiotic use, all patients remained free of symptoms. Resistance to either vancomycin or rifampin was not encountered. Biotyping of isolates with clostridial bacteriophages and bacteriocins suggested true relapse with the same organism in all patients studied, rather than reinfection with another strain. Vancomycin and rifampin in combination appear to be useful in the therapy of relapsing antibiotic-associated diarrhea due to C. difficile.

The experimental pathogenicity in Swiss mice of various strains of Nocardia isolated in soil of Tucumán (Argentina)

The isolation of Nocardia pathogenic for man in soil of Tucumán revealed the convenience of undertaking a study of their virulence, to evaluate any potential danger it may imply. Thirty three strains were studied: 28 N. brasiliensis, 3 N. asteroides and 2 N. caviae by inoculating albino Swiss mice into the footpads and intraperitoneally. The results obtained revealed the existence of Nocardia of variable aggresiveness in the soil of Tucumán.

Relationships between the physiological characteristics and pathogenicity of Nocardia brasiliensis

The analysis of 19 physiological properties of 28 strains of Nocardia brasiliensis isolated from soil reveal differences which could be of great value in distinguishing pathogenic from nonpathogenic strains.