Successful suppression of the early rejection of pig islets in monkeys

Primary nonfunction (PNF) is seen very frequently after xenogeneic transplantation of islets of Langerhans. In a pig-to-rat model we recently observed that no PNF occurs when the islets are kept in culture at 37 degrees C for 1-2 weeks prior to transplantation. In order to investigate the rejection mechanisms in a preclinical model, we transplanted cultured porcine islets under the capsule of both kidneys in four cynomolgous monkeys. Islets were isolated from adult sows by means of digestion with Liberase in University of Wisconsin solution (UWS). The digest was purified by a density gradient of OptiPrep in UWS. Highly purified (>95%) islets were cultured 1-2 weeks in RPMI. All monkeys showed significant titers of preformed anti-pig antibodies. The immunosuppression of the monkeys consisted of cyclophosphamide (Cy) (2 days), cyclosporin A (CsA), and prednisolone. Anticipating a fast rejection we carried out nephrectomies at different time points within 2 weeks after transplantation. Following unilateral nephrectomy, well-preserved islets with no signs of rejection were observed between 3 and 7 days posttransplant. Later, between days 11 and 15 posttransplant, histology in the first three animals demonstrated no islets. In the fourth monkey histology on day 11 showed islets with excellent morphology and some small focal infiltrates. The highest CsA blood levels (around 1000 ng/ml) were found in animals with the best graft survival. We conclude that cultured porcine islets can be grafted without hyperacute rejection in monkeys with preformed anti-pig antibodies. In the presence of high levels of CsA only marginal signs of a cellular immune response were observed 11 days after transplantation.

The neuroimmune-endocrine axis: pathophysiological implications for the central nervous system cytokines and hypothalamus-pituitary-adrenal hormone dynamics

Cytokines are molecules that were initially discovered in the immune system as mediators of communication between various types of immune cells. However, it soon became evident that cytokines exert profound effects on key functions of the central nervous system, such as food intake, fever, neuroendocrine regulation, long-term potentiation, and behavior. In the 80's and 90's our group and others discovered that the genes encoding various cytokines and their receptors are expressed in vascular, glial, and neuronal structures of the adult brain. Most cytokines act through cell surface receptors that have one transmembrane domain and which transduce a signal through the JAK/STAT pathway. Of particular physiological and pathophysiological relevance is the fact that cytokines are potent regulators of hypothalamic neuropeptidergic systems that maintain neuroendocrine homeostasis and which regulate the body's response to stress. The mechanisms by which cytokine signaling affects the function of stress-related neuroendocrine systems are reviewed in this article.

Combinatorial chemoprevention of intestinal neoplasia

A combination of two drugs afforded remarkable protection from intestinal neoplasia in APC(Min/+) mice, a murine model of human familial adenomatous polyposis (FAP). One of the drugs was sulindac, a prototypical non-steroidal anti-inflammatory drug with established chemopreventative activity. The second drug was EKI-569, a newly developed, irreversible inhibitor of the epidermal growth factor receptor kinase. Although 100% of the untreated APC(Min/+) mice developed approximately 20 polyps, nearly half the mice treated with these two agents developed no polyps at all. These results suggest a powerful strategy for the chemoprevention of human colonic neoplasia.

The quality of false memory over time: is memory for misinformation "remembered" or "known"?

The conscious quality of eyewitness memory for misinformation after different retention intervals was investigated in two experiments. Participants viewed computer-projected slides depicting a crime (encoding phase), read a narrative containing misinformation, and took a recall test about the original event. Remember/know judgments were made for each response. A "remember" judgment indicated that the participant vividly recalled seeing a detail in the encoding phase. A "know" judgment indicated that the participant believed that a detail was presented but did not vividly remember it. Generally, misinformation was more likely to be associated with a know judgment than with a remember judgment after a short retention interval. This outcome suggests that, in many cases, misleading information is judged as having a different subjective quality than memory for actual events. However, over a relatively long retention interval, misinformation that simply added new information about the event was more often judged as remembered.

Treatment of polycystic kidney disease with a novel tyrosine kinase inhibitor

Treatment of polycystic kidney disease with a novel tyrosine kinase inhibitor.

BACKGROUND

We have previously demonstrated an essential role for increased epidermal growth factor receptor (EGFR) activity in mediating renal cyst formation and biliary epithelial hyperplasia in murine models of autosomal recessive polycystic kidney disease (ARPKD). This study was designed to determine whether or not treatment with a newly developed inhibitor of EGFR tyrosine kinase activity (EKI-785) would reduce renal and biliary abnormalities in murine ARPKD.

METHODS

Balb/c-bpk/bpk (BPK) litters were treated with EKI-785, an EGFR-specific tyrosine kinase inhibitor. Animals were treated by intraperitoneal injection beginning at postnatal day 7 and were treated until postnatal day 24 or 48. EKI-785's effectiveness was measured by a reduction in the renal cystic index, an increased life span, and maintenance of normal renal function.

RESULTS

Treatment of BPK mice with EKI-785 resulted in a marked reduction of collecting tubule (CT) cystic lesions, improved renal function, decreased biliary epithelial abnormalities, and an increased life span. Untreated cystic animals died of renal failure at postnatal day 24 (P-24) with a CT cystic index of 4.8, a maximal urine osmolarity of 361 mOsm, and moderate to severe biliary abnormalities. Cystic animals treated with EKI-785 to postnatal day 48 (P-48) were alive and well with normal renal function, a reduced CT cystic index of 2.0 (P < 0.02), a threefold increased in maximum urinary concentrating ability (P < 0.01), and a significant decrease in biliary epithelial proliferation/fibrosis (P < 0.01).

CONCLUSION

This study demonstrates that EKI-785 has therapeutic effectiveness in improving histopathologic abnormalities and decreasing mortality in murine ARPKD.

Is supraspinatus pathology as defined by magnetic resonance imaging associated with clinical sign of shoulder impingement?

To examine the association between supraspinatus pathology and clinical sign of impingement, 42 workers with and 31 age-matched workers without signs of subacromial impingement had their shoulder examined by magnetic resonance imaging. All subjects were selected from an epidemiologic study evaluating the risk of shoulder impingement syndrome in relation to ergonomic exposure. Physical examination was conducted according to the same protocol and included assessment of shoulder function. Magnetic resonance images were evaluated in a blinded manner with regard to clinical status and age. Twenty-two (55%) subjects in the impingement group and 16 (52%) subjects in the control group had a pathologic supraspinatus tendon (odds ratio 1.13 [95% confidence interval 0.45 to 2.88]). The prevalence of supraspinatus pathology increased from 32% in the youngest to 48% in the middle and 72% in the oldest age group. The results of this study indicate that supraspinatus pathology is related to age rather than to clinical sign of impingement.

In vitro modulation of cyst formation by a novel tyrosine kinase inhibitor

BACKGROUND

Recessively transmitted polycystic kidney disease (PKD) in many murine models is characterized by the initial formation of proximal tubular cysts (stage 1), followed by growth and enlargement of renal collecting tubule (CT) cysts (stage 2). Previous studies have reported that stage 1 cyst formation and growth could be manipulated in vitro by using embryonic kidney explants and newborn explant microslices in organ culture.

METHODS

Microslices of postnatal kidneys cultured on Transwell tissue culture inserts allow experimental manipulation of stage 2 CT cyst development and growth. This system was used to test a potential therapeutic compound for treatment of PKD. This compound, EKI-785, modulates altered epidermal growth factor receptor (EGFR) expression in CT cysts by inhibition of EGFR autophosphorylation.

RESULTS

These studies demonstrate that: (a) minor modifications of the previously described organ culture system permit successful culture of more mature renal tissue, and (b) cystic explants treated with EGF and EKI-785 demonstrated a marked reduction in CT cystic lesions compared with cystic explants treated with EGF alone.

CONCLUSIONS

This study suggests that pharmacological strategies can be used to decrease EGFR tyrosine kinase activity and CT cyst formation and enlargement in murine PKD.

The toxic handler: organizational hero--and casualty

You've watched them comfort colleagues, defuse tense situations, and take the heat from tough bosses. You've seen them step in to ease the pain during layoffs and change programs. Who are they? The authors call them toxic handlers--managers who voluntarily shoulder the sandness, frustration, bitterness, and anger of others so that high-quality work continues to get done. Toxic handlers are not new. They are probably as old as organizations themselves. But there has never been a systematic study of the role they play in business. In this article, the authors introduce the role of toxic handlers, explaining what they do and why. Managing the pain of others is hard work. Toxic handlers save organizations from self-destructing, but they often pay a high price--emotionally, professionally, and sometimes physically. Some toxic handlers experience burnout; others suffer far worse consequences, such as ulcers and heart attacks. The authors contend that these unsung corporate heroes have strategic importance in today's business environment. Effective pain management can--and does--contribute to the bottom line. No company can afford to let talented employees burn out. Nor can it afford to have a reputation as an unhappy place to work. The authors offer practical advice for managers and organizations about how to support toxic handlers--before a crisis strikes. The role of toxic handler needs to be given the attention it deserves for everyone's benefit, because the health of employees is a key element in the long-term competitiveness of companies and of society.

Shoulder impingement syndrome in relation to shoulder intensive work

OBJECTIVES

To analyse the risk of shoulder impingement syndrome relative to shoulder intensive work.

METHODS

A cross sectional study of a historical cohort of 1591 workers employed between 1986 and 1993 at a slaughterhouse or a chemical factory. Workers not doing tasks in slaughtering or meat processing constituted the reference group. Intensity of shoulder work in meat processing tasks was assessed by video based observations. Information on shoulder disorders was collected by questionnaire and by physical examinations. Impingement syndrome was diagnosed when shoulder symptoms had been present for at least 3 months during the past year and there were signs of subacromial impingement in the corresponding shoulder at physical examination. Shoulder function was assessed at the same occasion with the Constant scoring technique. Prevalence of shoulder impingement syndrome was analysed according to job title and cumulative exposure.

RESULTS

Prevalence ratio for shoulder impingement syndrome was 5.27 (95% confidence interval (95% CI), 2.09 to 12.26) among currently working and 7.90 (95% CI, 2.94 to 21.18) among former slaughterhouse workers. Transformed model based prevalence ratios according to years in slaughterhouse work showed an overall association between cumulative exposure and risk for shoulder impingement syndrome.

CONCLUSIONS

This study supports the hypothesis that shoulder intensive work is a risk factor for impingement syndrome of the shoulder. Despite the historical cohort design healthy worker selection may have influenced the exposure-response relation found.

Occurrence of carpal tunnel syndrome among slaughterhouse workers

OBJECTIVES

The aim of this study was to examine the risk of carpal tunnel syndrome (CTS) among workers with daily occupational exposure to high-force and high-velocity manual work.

METHODS

The study was carried out retrospectively among a cohort of 1591 workers employed at a slaughterhouse or at a chemical factory; 1141 persons (71.7%) participated. Workers not doing tasks in slaughtering or meat processing constituted the reference group. Exposure assessments were made for 46 different tasks in slaughtering and meat processing from video-based observations at the workplace. CTS was diagnosed if there were current symptoms typical of CTS in combination with positive neurophysiological signs of CTS or if the subject had previously been operated on for CTS.

RESULTS

Altogether 1.6% of the reference group, 5.1% of the nondeboning slaughterhouse workers [prevalence ratio (PR) 3.23, 95% confidence interval (95% CI) 1.3-7.99] and 7.8% of the deboning slaughterhouse workers (PR 4.91, 95% CI 2.03-11.81) had CTS. Increased risk estimates persisted after adjustment for other potential risk factors by logistic regression. The prevalence of CTS in the dominant hand was equally increased in both groups of slaughterhouse workers (but only statistically significant for the workers in deboning tasks), while the prevalence of CTS in the nondominant hand was significantly increased only among the slaughterhouse workers in deboning tasks.

CONCLUSIONS

This study supports the hypothesis that daily high-velocity and high-force manual work is a risk factor for CTS.

Influence of long-term, low-dose, diuretic-based, antihypertensive therapy on glucose, lipid, uric acid, and potassium levels in older men and women with isolated systolic hypertension: The Systolic Hypertension in the Elderly Program. SHEP Cooperative Research Group

BACKGROUND

Previous studies often of short duration have raised concerns that antihypertensive therapy with diuretics and beta-blockers adversely alters levels of other cardiovascular disease risk factors.

METHODS

The Systolic Hypertension in the Elderly Program was a community-based, multicenter, randomized, double-blind, placebo-controlled clinical trial of treatment of isolated systolic hypertension in men and women aged 60 years and older. This retrospective analysis evaluated development of diabetes mellitus in all 4736 participants in the Systolic Hypertension in the Elderly Program, including changes in serum chemistry test results in a subgroup for 3 years. Patients were randomized to receive placebo or treatment with active drugs, with the dose increased in stepwise fashion if blood pressure control goals were not attained: step 1, 12.5 mg of chlorthalidone or 25.0 mg of chlorthalidone; and step 2, the addition of 25 mg of atenolol or 50 mg of atenolol or reserpine or matching placebo.

RESULTS

After 3 years, the active treatment group had a 13/4 mm Hg greater reduction in systolic and diastolic blood pressure than the placebo group (both groups, P<.001). New cases of diabetes were reported by 8.6% of the participants in the active treatment group and 7.5% of the participants in the placebo group (P=.25). Small effects of active treatment compared with placebo were observed with fasting levels of glucose (+0.20 mmol/L [+3.6 mg/dL]; P<.01), total cholesterol (+0.09 mmol/L [+3.5 mg/dL]; P<.01), high-density lipoprotein cholesterol (-0.02 mmol/L [-0.77 mg/dL]; P<.01) and creatinine (+2.8 micromol/L [+0.03 mg/dL]; P<.001). Larger effects were seen with fasting levels of triglycerides (+0.9 mmol/L [+17 mg/dL]; P<.001), uric acid (+35 micromol/L [+.06 mg/dL]; P<.001), and potassium (-0.3 mmol/L; P<.001). No evidence was found for a subgroup at higher risk of risk factor changes with active treatment.

CONCLUSIONS

Antihypertensive therapy with low-dose chlorthalidone (supplemented if necessary) for isolated systolic hypertension lowers blood pressure and its cardiovascular disease complications and has relatively mild effects on other cardiovascular disease risk factor levels.

Overcoming misinformation effects in eyewitness memory: effects of encoding time and event cues

Eyewitness memory is often distorted when misleading information is presented to subjects after encoding. Three experiments explored ways to overcome these misinformation effects. In Experiment 1, subjects viewed slides of a robbery, at a rate of four or seven seconds per slide. Five minutes later subjects were given a recognition test with few (1-3) or numerous (6-13) event cues. Providing numerous retrieval cues improved overall performance, but did not reduce the effects of misinformation. With week-long delays (Experiment 2) numerous retrieval cues did eliminate misinformation effects, but only when subjects viewed slides at the slower rate (seven seconds per slide). Experiment 3 essentially replicated this pattern, using a modified test to eliminate any biasing effects of distractors. Given adequate encoding and numerous retrieval cues, misinformation effects were eliminated, suggesting that under some conditions misinformation makes event memory inaccessible, but not unavailable.

The route of nutritional support in the critically ill: physiological and economical considerations

Although it generally is accepted that early enteral nutrition is of benefit to critically ill patients, there is little evidence to support this assertion. Nevertheless, enteral nutrition has many advantages over total parenteral nutrition (TPN), the latter being associated with several complications. Animal studies have shown that injury and infection can lead to gut atrophy and increased mucosal permeability. Translocation of bacteria and endotoxin in these animal models may initiate a systemic inflammatory response and cause multiple organ failure (MOF). Again, there is little direct evidence to suggest that similar mechanisms operate in humans. As a cause of MOF, simple splanchnic ischemia and reperfusion may be sufficient with no absolute requirement for translocation. In this setting, enteral nutrition may preserve splanchnic blood flow and prevent mucosal breakdown. Unfortunately there is a widespread misconception that gastric stasis, the absence of bowel sounds, and recent abdominal surgery preclude enteral feeding. There are few absolute contraindications to early enteral feeding and with motivated staff, the use of prokinetics, and the availability of jejunal feeding tubes, the majority of intensive care patients can be fed enterally. Enteral feeding is more cost effective than TPN, but TPN remains a common therapeutic intervention in the intensive care unit and represents a significant burden on health care budgets. Nutrition support teams have led to savings, particularly by identifying patients who have been inappropriately prescribed TPN and also by preventing excessive enteral feeding.

Immunosensitization of prostate carcinoma cell lines for lymphocytes (CTL, TIL, LAK)-mediated apoptosis via the Fas-Fas-ligand pathway of cytotoxicity

Several reports suggest that immunotherapy mediated by cytotoxic lymphocytes is beneficial in the destruction of drug-resistant tumor cells. Cytotoxic T lymphocytes kill target cells by two main mechanisms, namely by the perforin pathway and by the Fas-ligand (Fas-L) pathway. The role of the Fas-L pathway in tumor cell killing is not clear because many Fas(+)-expressing tumor cells are resistant to the Fas-L agonist cytotoxic anti-Fas antibody. The human prostate tumor cell lines (PC-3, DU145, and LnCAP) express Fas on the cell surface but are resistant to killing by anti-Fas antibody. This study examined the sensitivity of prostate tumor cells to Fas-L-mediated cytotoxicity and sensitization of the tumor cells by drugs to Fas-L-mediated killing. All three prostate tumor cell lines are resistant to Fas-L killing as determined by the use of the murine CTL hybridoma PMMI that kills only through the Fas-L pathway. However, the addition of subtoxic concentrations of CDDP or VP-16 significantly sensitized the PC-3 and DU145, but not LnCAP, tumor cells to Fas-L killing and apoptosis by PMMI. The sensitization of tumor cells by drugs was inhibited by neutralizing anti-Fas antibody. These findings demonstrate that immunoresistant Fas(+)-expressing DU145 and PC-3 prostate tumor cells can be sensitized by drugs to Fas-L killing. We then examined the role of Fas-L killing by TIL and LAK cells. All three prostate tumor cell lines were sensitive to killing by TIL and LAK and cell killing was primarily mediated through the Ca(2+)-dependent perforin pathway because it was blocked by the addition of EGTA/MgCl2. Sensitization by CDDP or VP-16 did not significantly augment killing of untreated tumor cells by TIL or LAK cells. However, in the presence of EGTA/MgCl2, the addition of CDDP or VP-16 significantly augmented killing of PC-3 and DU145, but not LnCAP, by TIL and LAK, and killing was blocked by neutralizing anti-Fas antibody. These findings demonstrate that both TIL and LAK exhibit a Fas-L-mediated killing pathway that is revealed once the perforin pathway is blocked by the Ca2+ chelator EGTA/MgCl2. Altogether, these findings show that drug-resistant, Fas(+)-expressing PC-3 and DU145 prostate tumor cells can be sensitized by CDDP and VP-16 to killing by Fas-L-bearing CTL, TIL, and LAK cells. Sensitization of tumor cells by drugs may augment the efficacy of immunotherapy in the eradication of tumor cells that are resistant to Fas-L-mediated killing.

Nucleic acid immunization of chimpanzees as a prophylactic/immunotherapeutic vaccination model for HIV-1: prelude to a clinical trial

Vaccine development strategies have often utilized recombinant envelope glycoproteins which usually generate strong humoral immune responses but which do not generate strong cytotoxic T lymphocytes (CTL). A recent novel experimental vaccination approach involves the technology known as nucleic acid immunization in which DNA plasmids expressing a gene of interest is injected intramuscularly in experimental animals. These expressed proteins then are presented to the immune system with the subsequent development of strong antibody and cellular (particularly CTL) immune responses. These types of immune responses have been elicited in rodents as well as nonhuman primates including chimpanzees. Results from studies on nucleic acid immunization of HIV-1 infected chimpanzees with envelope glycoprotein expressing constructs indicated that this method was able to decrease substantially HIV-1 viral load in these chimpanzees. These data are useful for the development and implementation of human phase I clinical trials with HIV constructs expressing various genes from the HIV-1 genome.

Chemosensitization of human prostate carcinoma cell lines to anti-fas-mediated cytotoxicity and apoptosis

Androgen ablation has been an effective treatment in patients with advanced prostate cancer. However, most treated patients develop hormonally resistant disease and do not respond to conventional chemotherapy. Immunotherapy against prostate cancer is an alternative approach in overcoming hormonal/drug-resistant prostate cancer. Cytotoxic immune lymphocytes kill target cells via the perforin/granzyme and the Fas-ligand (Fas-L) pathways. We hypothesize that tumor cells respond poorly to immunotherapy by developing resistance to killing by the Fas-L mechanism. This study investigated whether prostate tumor cells are sensitive to Fas-mediated killing. The human prostate carcinoma cell lines DU145, PC-3, and LnCAP were examined for their sensitivity to killing and apoptosis by the Fas-L agonist anti-Fas antibody and CTLs. All three lines moderately expressed the Fas antigen on the cell surface; however, all three lines were relatively resistant to cytotoxicity mediated by anti-Fas (CH-11) antibody. Pretreatment of DU145 and PC-3 with subtoxic concentrations of drugs followed by anti-Fas antibody resulted in synergistic cytotoxicity and apoptosis, whereas only an additive effect was obtained with LnCAP. Chemosensitization with drugs and anti-Fas was completely blocked by the addition of neutralizing anti-Fas antibody. The murine CTL hybridoma, PMMI, which kills only via the Fas-L pathway, was able to kill chemosensitized PC-3 and DU145 but not LnCAP cells. Furthermore, this cytotoxicity was blocked by anti-Fas neutralizing antibody. Chemosensitization of PC-3 and DU145 prostate tumor cells was not due to up-regulation of Fas-receptor antigen expression. Treatment of tumor cells with cisplatin did not down-regulate the antiapoptotic genes bcl-2, FAP-1, and c-myc. Further, there was no induction by cisplatin of Fas-L on the tumor cells, thus ruling out Fas/Fas-L-mediated autologous killing. These findings demonstrate that pretreatment of drug-resistant/CTL-resistant prostate DU145 and PC-3 tumor cells with subtoxic concentrations of certain chemotherapeutic drugs sensitizes the tumor cells to Fas-mediated cytotoxicity. These findings suggest that chemosensitization of tumor cells should optimize the response to immunotherapeutic interventions in the treatment of hormone-resistant/drug-resistant prostate cancer.

Protection of chimpanzees from high-dose heterologous HIV-1 challenge by DNA vaccination

Novel approaches for the generation of more effective vaccines for HIV-1 are of significant importance. In this report we analyze the immunogenicity and efficacy of an HIV-1 DNA vaccine encoding env, rev and gag/pol in a chimpanzee model system. The immunized animals developed specific cellular and humoral immune responses. Animals were challenged with a heterologous chimpanzee titered stock of HIV-1 SF2 virus and followed for 48 weeks after challenge. Polymerase chain reaction coupled with reverse transcription (RT-PCR) results indicated infection in the control animal, whereas those animals vaccinated with the DNA constructs were protected from the establishment of infection. These studies serve as an important benchmark for the use of DNA vaccine technology for the production of protective immune responses.

Resistance of previously infected chimpanzees to successive challenges with a heterologous intraclade B strain of human immunodeficiency virus type 1

To test whether the protective effects of attenuated simian immunodeficiency virus vaccines in macaques were applicable to the human immunodeficiency virus type 1 (HIV-1)-chimpanzee system, two groups of animals, previously infected with HIV-1(IIIB) or HIV-1(SF2) were each challenged with a heterologous clade B virus, HIV-1(DH12). Following challenge, the parameters measured included virus isolation (from plasma, peripheral blood mononuclear cells, and lymph node tissue); quantitative DNA PCR using primers capable of distinguishing HIV-1(IIIB), HIV-1(SF2), and HIV-1(DH12) from one another; and serologic assays to monitor changes in binding and neutralizing antibodies. In contrast to an HIV-1-naive chimpanzee that rapidly became infected following the inoculation of HIV-1(DH12), the two chimpanzees previously infected with HIV-1(IIIB) resisted repeated and escalating inoculations of HIV-1(DH12), as monitored by virus isolation and PCR. The two animals previously infected with HIV-1(SF2) became infected with HIV-1(DH12) but in contrast to the case with the HIV-1-naive chimpanzee, no cell-free viral RNA was detected in the plasma by the branched DNA procedure and levels of peripheral blood mononuclear cell-associated viral DNA were reduced 35- to 50-fold.