Epitope identification for a panel of anti-Sinorhizobium meliloti monoclonal antibodies and application to the analysis of K antigens and lipopolysaccharides from bacteroids

In two published reports using monoclonal antibodies (MAbs) generated against whole cells, Olsen et al. showed that strain-specific antigens on the surface of cultured cells of Sinorhizobium meliloti were diminished or absent in the endophytic cells (bacteroids) recovered from alfalfa nodules, whereas two common antigens were not affected by bacterial differentiation (P. Olsen, M. Collins, and W. Rice, Can. J. Microbiol. 38:506-509, 1992; P. Olsen, S. Wright, M. Collins, and W. Rice, Appl. Environ. Microbiol. 60:654-661, 1994). The nature of the antigens (i.e., the MAb epitopes), however, were not determined in those studies. For this report, the epitopes for five of the anti-S. meliloti MAbs were identified by polyacrylamide gel electrophoresis-immunoblot analyses of the polysaccharides extracted from S. meliloti and Sinorhizobium fredii. This showed that the strain-specific MAbs recognized K antigens, whereas the strain-cross-reactive MAbs recognized the lipopolysaccharide (LPS) core. The MAbs were then used in the analysis of the LPS and K antigens extracted from S. meliloti bacteroids, which had been recovered from the root nodules of alfalfa, and the results supported the findings of Olsen et al. The size range of the K antigens from bacteroids of S. meliloti NRG247 on polyacrylamide gels was altered, and the epitope was greatly diminished in abundance compared to those from the cultured cells, and no K antigens were detected in the S. meliloti NRG185 bacteroid extract. In contrast to the K antigens, the LPS core appeared to be similar in both cultured cells and bacteroids, although a higher proportion of the LPS fractionated into the organic phase during the phenol-water extraction of the bacteroid polysaccharides. Importantly, immunoblot analysis with an anti-LPS MAb showed that smooth LPS production was modified in the bacteroids.

A consumer-oriented model for evaluating computer-assisted instructional materials for medical education

Computer-assisted instruction (CAI) can enhance medical education, but course directors and curriculum designers need thorough, credible evaluative data to make sound decisions about procuring and implementing CAI programs. There has been extensive research on the merits of CAI in general (although much of it is flawed by methodologic shortcomings), but sufficient evaluative data on specific programs are rarely available. The author proposes that a consumer-oriented model would be useful for evaluating CAI programs, and he discusses one published, consumer-oriented evaluation of a multimedia CAI program for ophthalmology students. The author contends that if CAI programs were routinely evaluated using the consumer-oriented model, and if CAI program developers used this model to evaluate their programs during the developmental phase, medical educators would be better able to choose and implement the programs that would best serve their needs.

Magnesium modifies the responses of platelets to inhibitory agents which act via cAMP

This study has investigated the interaction of raised extracellular magnesium and agents which act via cAMP with respect to inhibition of platelet aggregation and effects on platelet cAMP accumulation. Iloprost (3 ng/ml) and PGD2 (0.2 microgram/ml) each caused time dependent increases in platelet cAMP which were significantly greater in the presence of 3 mM added MgSO4 (p < 0.01). Addition of ADP (5 microM) resulted in a fall in cAMP which remained higher in the presence of MgSO4 (p < 0.01). Forskolin (5 micrograms/ml) and DN9693 (100 microM) also caused increments in platelet cAMP but these responses were not influenced by added MgSO4. Addition of ADP resulted in a further increase in cAMP which was augmented by MgSO4 (p < 0.03). This increase was abolished by adenosine deaminase (1.2 U/ml). These experiments show that MgSO4 can modify the cAMP responses produced by iloprost and PGD2 and by forskolin and DN9693 when ADP is present. It appears that as well as inhibiting, ADP can also stimulate cAMP production under certain experimental conditions. This appears to be due to breakdown of ADP to adenosine.

Magnesium Modifies the Responses of Platelets to Inhibitory Agents which Act Via cAMP

This study has investigated the interaction of raised extracellular magnesium and agents which act via cAMP with respect to inhibition of platelet aggregation and effects on platelet cAMP accumulation.

Iloprost (3 ng/ml) and PGD2 (0.2 μg/ml) each caused time dependent increases in platelet cAMP which were significantly greater in the presence of 3 mM added MgS04 (p <0.01). Addition of ADP (5 μM) resulted in a fall in cAMP which remained higher in the presence of MgS04 (p <0.01).

Forskolin (5 μg/ml) and DN9693 (100 μM) also caused increments in platelet cAMP but these responses were not influenced by added MgS04. Addition of ADP resulted in a further increase in cAMP which was augmented by MgS04 (p <0.03). This increase was abolished by adenosine deaminase (1.2 U/ml).

These experiments show that MgS04 can modify the cAMP responses produced by iloprost and PGD2 and by forskolin and DN9693 when ADP is present. It appears that as well as inhibiting, ADP can also stimulate cAMP production under certain experimental conditions. This appears to be due to breakdown of ADP to adenosine.

The child is father of the man. Wordsworth's Ode: Intimations of immortality and his secret sharers

William Wordsworth's "Ode: Intimations of Immortality" is manifestly about both the poet's loss of inspirational perceptive powers and emotional intensity with age, and the compensations of maturity. It also refers to the poet's fear that he might lose his "secret sharers," real or fantasied, consciously or unconsciously conceived parent substitutes for whom and with whom one creates. Wordsworth anticipated that with his upcoming marriage he would lose his sister Dorothy and his close friend and collaborator Samuel Taylor Coleridge, who played important roles in his creativity. Optimism and relief replaced sadness when he realized that he was not deprived of his sharers. The concepts of "secret sharers" and "collective alternates" for whom one creates are intimately related.

Examining roles: home care & public health in disease prevention & health promotion

The New Mexico Association for Home Care is conducting a survey of home care and public health professionals to determine the current industry views on prevention and home care. The results will be important for the whole industry, possibly in setting guidelines for prevention activities. Agencies interested in presenting their views may contact the New Mexico Association for Home Care.

Detection of bluetongue virus in clinical samples by polymerase chain reaction

A previously described bluetongue virus (BTV) serogroup polymerase chain reaction (PCR) assay was applied to clinical samples. The sensitivity of the BTV serogroup PCR was increased by the use of non-radioactive chemiluminescent hybridization. Unfractionated whole blood samples from rams experimentally inoculated with cell culture-adapted BTV-11 UC-8 were analyzed by virus isolation (VI) on Vero cells and PCR. VI and PCR were in agreement, with the exception of 3 blood samples that were VI negative and PCR positive. In semen spiked with BTV-11 UC-8, PCR detected as little as 1.6 x 10(2) plaque-forming units of BTV/ml of semen. BTV in the spleen of a sheep submitted for necropsy for suspect BTV infection was detected by both PCR and VI in embryonated chicken eggs. BTV PCR with nonradioactive chemiluminescent hybridization resulted in a level of sensitivity comparable to that of VI and likely more sensitive than VI on Vero cells for blood. This BTV PCR has great promise for rapid, sensitive, and specific detection of active BTV infection in a variety of clinical samples.

Developmental transformations: the Isakower phenomenon as an example

A review of the literature, and clinical analytic material suggest that the Isakower phenomenon and its variants consist of representations or sense memory traces of the original infantile feeding experiences integrated with later representations of experiences during the anal and oedipal stages, latency, and even later. With progressive development, memories of earlier experiences are transformed with regard to function, form, content, and meaning.

Changes in G-actin after platelet activation in platelet rich plasma

We have used the DNase I inhibition assay to study changes in G-actin after platelet activation in platelet-rich plasma (PRP) induced by ADP. Because of problems associated with depolymerization of F-actin after lysis of ADP-activated platelets in the presence of plasma, G-actin was measured using a lysis buffer that contained formaldehyde to prevent any depolymerization of F-actin. Different patterns of response were seen depending on the concentration of ADP used, and these were modified by avoiding aggregation by either not stirring the sample or by adding EDTA. The results show rapid conversion of G-actin to F-actin in association with shape change, and there is a further decrease in G-actin associated with irreversible platelet aggregation. Thus evidence is presented that actin polymerization occurs in two phases after ADP stimulation.

Quality assessment of cyclosporine monitoring by 32 Canadian laboratories

The Canadian Quality Assurance Program was initiated in June 1989, and is a voluntary program which currently encompasses all 32 laboratories involved in the measurement of cyclosporine (CsA) across Canada. Two whole blood samples from control or clinical patients (kidney, liver and heart) containing unknown concentrations of CsA are circulated to each participating laboratory monthly, and analyzed by all techniques employed within that laboratory. Four analytical methods are currently employed: HPLC (n = 4). Sandimmun SP (n = 3), CycloTrac SP (n = 27) and TDx (n = 3). Four laboratories reported survey results in more than one methodology. Results from all participating centers are analyzed monthly. The mean, SD, standard deviation index and range are reported to each laboratory with information coded to preserve confidentiality. Accuracy, precision, recovery, analytical specificity, linearity and blank studies have been performed. This report covers the period from June 1989 to April 1990.

Therapeutic monitoring of cyclosporine: impact of a change in standards on 125I-monoclonal RIA performance in comparison with liquid chromatography

This study examines the measurement of cyclosporine (CsA) by 125I-monoclonal RIA, and describes the impact of the recent change in the standard curve provided. CsA concentrations in serum and whole-blood control samples measured by 125I-RIA were initially 8-18% higher than those by HPLC. During the first two months of 1989, a significant and sustained deviation in the 125I-RIA produced results that exceeded the HPLC results by 21-28% (P less than 0.001). Introduction of the new standard curve in March 1989 returned the concentration of the whole-blood controls to the previous range (11-12% above HPLC, P less than 0.001). Measurement of clinical samples from heart, liver, and bone-marrow graft recipients by 125I-RIA by both old and new kit standards produced a close linear correlation (y = 0.89 x - 19.02; r = 0.99; n = 75, range = 40-850 micrograms/L), with use of the new standards yielding results 82 (SD 8)% of those with the preceding assay. However, even with the new standard curve, CsA concentrations by 125I-RIA in the clinical samples exceeded those by HPLC by a factor of 1.37 (SD 0.18) to 1.52 (SD 0.19). Segregation for transplant type did not affect the RIA/HPLC ratio. The results suggest cross-reactivity of the 125I-RIA with material present in vivo.

Therapeutic monitoring of cyclosporine: impact of a change in standards on 125I-monoclonal RIA performance in comparison with liquid chromatography

This study examines the measurement of cyclosporine (CsA) by 125I-monoclonal RIA, and describes the impact of the recent change in the standard curve provided. CsA concentrations in serum and whole-blood control samples measured by 125I-RIA were initially 8-18% higher than those by HPLC. During the first two months of 1989, a significant and sustained deviation in the 125I-RIA produced results that exceeded the HPLC results by 21-28% (P less than 0.001). Introduction of the new standard curve in March 1989 returned the concentration of the whole-blood controls to the previous range (11-12% above HPLC, P less than 0.001). Measurement of clinical samples from heart, liver, and bone-marrow graft recipients by 125I-RIA by both old and new kit standards produced a close linear correlation (y = 0.89 x - 19.02; r = 0.99; n = 75, range = 40-850 micrograms/L), with use of the new standards yielding results 82 (SD 8)% of those with the preceding assay. However, even with the new standard curve, CsA concentrations by 125I-RIA in the clinical samples exceeded those by HPLC by a factor of 1.37 (SD 0.18) to 1.52 (SD 0.19). Segregation for transplant type did not affect the RIA/HPLC ratio. The results suggest cross-reactivity of the 125I-RIA with material present in vivo.

Acute illnesses necessitating urgent abdominal surgery in neutropenic cancer patients: description of 14 cases and review of the literature

Through a review of our experience and the literature, the cases of 56 neutropenic cancer patients requiring urgent abdominal surgery have been studied. The most common underlying diagnosis of malignant disease was leukemia (70%), and the most common intra-abdominal disease discovered at surgery was neutropenic enteropathy (61%). Major postoperative complications occurred in 50% of cases. The 30-day postoperative mortality was 32%, and the determinant 6-month survival was 34%. Abdominal pain in a neutropenic cancer patient calls for a thorough evaluation of its cause and careful serial examinations. Evidence of a surgically treatable disease or failure to respond to medical therapy for a presumed medically treatable disease should prompt surgical intervention.

A phase I study of hepatic arterial infusion using difluoromethylornithine

Ten patients with metastatic disease to the liver were treated with difluoromethylornithine (DFMO) administered by continuous hepatic arterial infusion. Two of nine evaluable patients had an objective partial response. Stable disease was recorded in three patients. Ototoxicity was encountered in all patients who received a daily dose of DFMO equal to or greater than 1.0 g/m2.

From protomasochism to masochism. A developmental view

A developmental view may help clarify confusions that exist regarding masochism. Following Loewenstein, I suggest that protomasochism be distinguished from masochism. Protomasochism comprises conditions prior to the oedipal period which may lead to masochism. Preoedipal precursors of masochism are organized and transformed during the oedipal stage and later. A conscious or unconscious genital sexual fantasy in which pain is an integral part may appear at that time. The demonstration of such a fantasy is essential for the definitive diagnosis of masochism. It is overdetermined and may result from a variety of dynamic configurations and genetic origins. In making those suggestions, I assume, following Freud, that erotogenic masochism is basic to all forms of masochism.

Patterns and determinants of rectal prolapse in a herd of pigs

A prospective cohort study was designed to describe the patterns and to determine the factors associated with the risk of rectal prolapse in a commercial swine herd in California, USA. Thirty (1.0 per cent) of 2862 pigs prolapsed between 12 and 28 weeks of age with the peak incidence occurring in 14- to 16-week-old pigs. The overall prolapse rate was 9.1 cases per 100,000 days at risk. Prolapse rates were highest during the winter and autumn months. Other factors associated with an increased risk of prolapse were maleness (relative risk 2.3) birthweight less than 1000 g (relative risk 3.4) Yorkshire boar A (relative risk 2.8) and dams of litter number 1 (relative risk 14.9), 2 (relative risk 8.2) and 3 (relative risk 9.8). No evidence was found to support the hypothesis that diarrhoea and coughing are factors associated with a risk of prolapse.

Species-specificity of estradiol regulated growth factors in breast cancer

Recent evidence indicates that autocrine/paracrine mechanisms may mediate the mitogenic effect of estradiol (E2) both in human and experimental breast cancer. However, the species-specificity of E2-regulated growth factors with regard to their biologic action has not been evaluated. To test this issue, we examined, in the soft agar clonogenic assay, the colony-stimulating activity in human breast cancers of conditioned media obtained from rat mammary carcinomas exposed to E2 (rat E2-CM). Of 22 primary human breast cancers plated in soft agar in the absence of serum, 18 (82%) successfully grew with a mean colony number of 62.4 +/- 9.8 (S.E.M.) (range 14-193). Rat E2-CM significantly stimulated colony formation in 10/18 (56%) human breast cancers to 155 +/- 11% (S.E.M.) of control. E2 administration (10(-9) M) in these tumors had a virtually identical overall effect (154 +/- 13% of control colony number). In the remaining eight tumors (44%), neither rat E2-CM nor E2 had, in general, a significant colony-stimulating effect. The growth-promoting action of rat E2-CM and E2 was not influenced by the hormone receptor status of the tumor. These results suggest that E2-regulated growth factors may not be species-specific, at least with regard to their colony-stimulating effects in soft agar.

Metastatic phenotype in murine cells transfected with human DNA

DNAs of cell lines derived from human metastatic tumors were transfected into tumorigenic, nonmetastasizing murine cells (BALB 3T12-3) to determine if the capacity to metastasize could be conferred by this transfer of portions of the human genome. Using the calcium phosphate method, whole cell DNA was cotransfected into the murine cells along with a neomycin-resistance gene. Recipient murine cells (10(6] which grew in neomycin, indicating successful transfection, were injected via tail vein into 4- to 6-week-old male athymic nude mice. Animals were sacrificed if they appeared ill or at times up to 24 weeks after injection if they remained healthy. Murine cells transfected with DNA from one cell line derived from a hepatic metastasis of a human pancreatic adenocarcinoma (NCI-ZRY) formed experimental pulmonary metastases in 11 of 13 animals injected. Neither murine cells (unmanipulated BALB 3T12-3 cells) nor murine cells transfected with DNA from the same cell type (BALB 3T12-3 cells transfected with BALB 3T12-3 DNA) produced experimental metastases when each cell type was injected into 20 and 10 animals, respectively (P2 less than 0.0001). The results are consistent with the hypothesis that expression of a structural or regulatory protein encoded on human DNA conferred the metastatic phenotype to the recipient murine cells.

Evaluation of the utility of a radioimmunoassay for serum CA 19-9 levels in patients before and after treatment of carcinoma of the pancreas

By radioimmunoassay we determined circulating levels of a tumor-associated antigen, CA 19-9, in 47 patients with pancreatic adenocarcinoma, to learn if serial testing was useful in predicting prognosis or in detecting disease progression. Before treatment, 42 (89%) had an abnormal serum level, and 45 (96%) had an abnormal level at some time during the disease course. A pretreatment value of less than 1,000 U/mL (normal, less than or equal to 37 U/mL) was found in 38 patients; 20 (53%) had resectable disease. One of nine patients (11%) with a pretreatment value greater than 1,000 U/mL had resectable disease (P2 = .05). Among 14 patients who underwent pancreatectomy and were studied serially, the CA 19-9 level normalized in eight; seven (88%) survived greater than or equal to 18 months. Six patients whose levels did not normalize after pancreatectomy all died in less than 12 months (P2 less than .005). Greatly elevated levels occurred in 11 patients after pancreatectomy 1 to 7 months before clinically apparent recurrence. The other three patients without significant elevations remain clinically free of disease. The data suggest that serial determination of serum CA 19-9 levels are useful as a prognostic indicator and in detecting disease recurrence following pancreatectomy. Concurrent determinations of carcinoembryonic antigen (CEA) levels showed abnormal preoperative values in 28 of 46 patients tested (61%). Concurrent serial postoperative determinations of CEA were available in ten patients. Whereas CA 19-9 values clearly indicated eight recurrences, CEA was helpful in only four. In this small group of patients, CA 19-9 was a better predictor of recurrence.

Anorectal infections in patients with malignant diseases

Fifty-seven episodes of anorectal infection in 44 patients with malignant diseases primarily leukemia or lymphoma, have been retrospectively reviewed. Seventeen patients died in hospital, but only in seven cases was the anorectal infection a major contributing cause of death. The most important prognostic indicator of outcome was number of days of neutropenia during the infectious episode. Cultures obtained at the time of surgical drainage or by needle aspiration of the wound revealed multiple organisms in 26 of 29 instances, and anaerobic organisms were the commonest isolates. Anorectal infection was controlled in 28 (55%) of 51 treatment courses when antibiotics were the only treatment given. However, if the antibiotic regimen included both an aminoglycoside and an antibiotic with anaerobic coverage, control of infection was observed in 15 (88%) of 17 cases. There were 26 surgical procedures performed, with acceptable morbidity. Infection was controlled in 19 (73%) of 26 cases treated with surgery and antibiotics. The results support managing most of these infections initially with medical treatment, using an antibiotic regimen that includes an aminoglycoside and a specific drug against anaerobes. Surgery is recommended if there is obvious fluctuance, a significant amount of necrotic tissue evident, or progression of the infection locally or continued sepsis after an adequate antibiotic trial.