Left ventricular assist device exchange for persistent infection: a case series and review of the literature.

Left ventricular assist device (LVAD) exchange for control of infection may be an option for the treatment of persistent and severe infections of the LVAD. Data are limited regarding the indications for device exchange, methods for exchanging infected devices, post-exchange antimicrobial management, and outcomes of such patients. We report a series of cases in which an exchange was performed for persistent LVAD infection, review the literature on LVAD exchange and surgical techniques for these infectious complications, and suggest management strategies from a multidisciplinary perspective.

Angiotensin and renin in rat and dog brain.

An enzyme with the characteristics of classical renin was isolated from brain extracts of nephrectomized dogs. This enzyme is thermolabile, nondialyzable, and forms a vasoconstrictive material when incubated with renin plasma substrate at pH 7. A short lasting pressor activity was also found in brain extracts of dogs and rats. This activity was due to a substance identified by chemical and pharmacological tests as angiotensin. Countercurrent distribution of brain extracts of rats showed that 38% of the pressor activity corresponded to angiotensin II and the remainder to angiotensin I. A remarkable correlation was found between angiotensin and norepinphrine concentrations in different portions of the encephalon of the dog.

Apparent anomalies in nuclear feulgen-DNA contents. Role of systematic microdensitometric errors.

The Feulgen-DNA contents of human leukocytes, sperm, and oral squames were investigated by scanning and integrating microdensitometry, both with and without correction for residual distribution error and glare. Maximally stained sperm had absorbances which at lambdamax exceeded the measuring range of the Vickers M86 microdensitometer; this potential source of error could be avoided either by using shorter hydrolysis times or by measuring at an off-peak wavelength. Small but statistically significant apparent differences between leukocyte types were found in uncorrected but not fully corrected measurements, and some apparent differences disappeared when only one of the residual instrumental errors was eliminated. In uncorrected measurements, the apparent Feulgen-DNA content of maximally stained polymorphs measured at lambdamax was significantly lower than that of squames, while in all experimental series uncorrected measurements showed apparent diploid:haploid ratios significantly greater than two. In fully corrected measurements no significant differences were found between leukocytes and squames, and in four independent estimations the lowest diploid:haploid ratio found was 1.99 +/- 0.05, and the highest 2.03 +/- 0.05. Discrepancies found in uncorrected measurements could be correlated with morphology of the nuclei concerned. Glare particularly affected measurements of relatively compact nuclei such as those of sperm, polymorphs and lymphocytes, while residual distribution error was especially marked with nuclei having a high perimeter:area ratio (e.g. sperm and polymorphs). Uncorrected instrumental errors, especially residual distribution error and glare, probably account for at least some of the previously reported apparent differences between the Feulgen-DNA contents of different cell types. On the basis of our experimental evidence, and a consideration of the published work of others, it appears that within the rather narrow limits of random experimental error there seems little or no reason to postulate either genuine differences in the amounts of DNA present in the cells studied, or nonstoichiometry of a correctly performed Feulgen reaction.

Nalidixic acid, oxolinic acid, and novobiocin inhibit yeast glycyl- and leucyl-transfer RNA synthetases.

Nalidixic acid and novobiocin inhibit the aminoacylation and pyrophosphate exchange activities of glycyl- and leucyl-transfer RNA synthetases from bakers' yeast. Similar types of inhibition are observed for both enzymes, suggesting similar mechanisms. The potency of these inhibitors is comparable to that observed for their inhibition of in vivo DNA synthesis in eukaryotic cells.

Tumor necrosis factor alpha interferes with the cell cycle of normal and papillomavirus-immortalized human keratinocytes.

We have shown that normal and human papillomavirus (HPV) type 16 immortalized human foreskin keratinocytes are growth inhibited by tumor necrosis factor alpha (TNF-alpha), whereas HPV-18- and SV40-immortalized keratinocytes are resistant to this cytokine (1). In this report, we investigated the expression of mitotic regulatory proteins, such as cyclin A, cyclin B, and p34cdc2. After exposure to TNF-alpha, normal and HPV-16-immortalized cells exhibited a dramatic decrease in the expression of these proteins. In contrast, no alteration in the levels of these proteins was observed after treatment of the resistant cell lines, as well as two HPV-positive cervical carcinoma cell lines. Expression of cyclin E does not seem to be modulated by TNF-alpha in any of the cells tested. On the other hand, cyclin D1, expression is slightly increased in normal keratinocytes and in the HPV-16-immortalized cells, whereas no alteration was observed in the HPV-18-transfected cells. The phosphorylation state of pRb correlated with cell growth; sensitive cells, which accumulate in G0-G1, after exposure to TNF-alpha, exhibited an accumulation of hypophosphorylated pRb, whereas no effect on pRb phosphorylation was observed for HPV-18-immortalized cells. These results clearly correlate with TNF-alpha-induced growth arrest in G0-G1.

ErbB-4 ribozymes abolish neuregulin-induced mitogenesis.

The epidermal growth factor-like receptor tyrosine kinase (ErbB) family is frequently overexpressed in a variety of human carcinomas, including breast cancer. To assist in characterizing the role of ErbB-4 in breast cancer, we generated three specific hammerhead ribozymes targeted to the ErbB-4 mRNA. These ribozymes, Rz6, Rz21, and Rz29, efficiently catalyzed the specific cleavage of ErbB-4 message in a cell-free system. We demonstrated that the neuregulin-induced mitogenic effect was abolished in ribozyme Rz29- and Rz6-transfected 32D/ErbB-4 cells. Inhibition of mitogenesis was characterized by ribozyme-mediated down-regulation of ErbB-4 expression. In addition, we provide the first evidence that different threshold levels of ErbB-4 expression and activation correlate with different responses to neuregulin stimulation. High levels of ErbB-4 expression, phosphorylation, and homodimerization are necessary for neuregulin-stimulated, interleukin 3-independent cell proliferation in the 32D/E4 cells. In the case of Rz29-transfected 32D/E4 cells, low levels of ErbB-4 expression allowed neuregulin-induced phosphorylation but were insufficient to couple the activated receptor to cellular signaling. Furthermore, expression of the functional ErbB-4 ribozyme in T47D human breast carcinoma cells led to a down-regulation of endogenous ErbB-4 expression and a reduction of anchorage-independent colony formation. These studies support the use of ErbB-4 ribozymes to define the role of ErbB-4 receptors in human cancers.

Activation of the focal adhesion kinase signal transduction pathway in cervical carcinoma cell lines and human genital epithelial cells immortalized with human papillomavirus type 18.

The inappropriate activation of protein-tyrosine kinases (PTKs) has been associated with initiation and progression of several types of human cancers. We therefore postulated that immortalization by DNA tumor viruses results in the induction of PTKs fundamental to these processes. An RT-PCR-based screen was thus used to identify PTKs that were abundantly expressed in HPV-18-immortalized epithelial cells and HPV-containing carcinoma cell lines. One of the genes isolated in this screen was the focal adhesion kinase (FAK; pp125FAK), a cytoplasmic protein kinase that is activated in v-src transformed cells or by stimulation with mitogenic polypeptides. FAK also becomes catalytically active upon integrin engagement with extracellular matrix proteins, such as fibronectin. We found that FAK expression and activity were significantly elevated in HPV-18 E6/E7-immortalized human genital epithelial cells relative to their primary cell counterparts. Protein expression and tyrosine phosphorylation of the putative FAK substrate, paxillin, were also notably increased upon HPV-18 immortalization of genital epithelial cells and in HPV-containing cervical carcinoma cell lines. Most significantly, these cells expressed markedly higher levels of both intracellular and extracellular fibronectin, thus providing a mechanism for activation of FAK and increased tyrosine phosphorylation of paxillin. These findings suggest a role for the integrin/FAK-mediated signaling pathway in cervical carcinogenesis and represent one of the first demonstrations of a tyrosine kinase whose activity is elevated following viral immortalization.

Ion channels formed by transcription factors recognize consensus DNA sequences.

Transcription factors (TFs) are proteins which bind to specific DNA sequences and thus participate in the regulation of the initiation of transcription. We report in this communication our observations that several of these proteins interact with lipid membranes and form ion-permeable channels. For each of the TFs that we studied, the single channel conductance was distinctively different, i.e. each TF had its own electrical signature. More importantly, we show for the first time that addition of cognate double-stranded DNA sequences leads to a specific response: an increase in the conductance of the TF-containing membrane. Strikingly, the effect of cognate DNA was observed when it was added to the trans-side of the membrane (opposite to where the TF was added), strongly suggesting that the TFs span the membrane and that the DNA-binding domain is trans-accessible. Alterations in the primary structure of the TF factors in their basic and DNA-binding regions change the characteristics of the conductance of the protein-containing membranes as well as the response to DNA addition, reinforcing the notion that the changes we measure are due to specific interactions.

De novo immunosuppression with sirolimus and tacrolimus in heart transplant recipients compared with cyclosporine and mycophenolate mofetil: a one-year follow-up analysis.

BACKGROUND: Limited data exist regarding the safety and efficacy of sirolimus in combination with a calcineurin inhibitor in heart transplant recipients. METHODS: From January 2001 to June 2002, 31 de novo heart transplant recipients (treatment group) received a combination of sirolimus, tacrolimus, low-dose rabbit antithymocyte globulin, and glucocorticoids. Outcomes, such as actuarial survival, rate of rejection, incidence of infection, probability of developing diabetes mellitus, renal function, platelet and white blood cell counts, and incidence of coronary artery disease at 1 year, were compared with a cohort of 25 patients (control group) who underwent transplantation primarily in 2000 and in early 2002 treated with cyclosporine, mycophenolate mofetil, and glucocorticoids. All patients were followed up for at least 12 months. RESULTS: Kaplan-Meier actuarial 1-year survival rates were equivalent between groups (97% for the treatment group and 88% for the control group), as was freedom from allograft rejection (48% and 42% for treatment and control groups, respectively). No cases of transplant arteriopathy were noted within the first posttransplantation year. Renal function was not significantly affected in either group. There was a striking increased incidence of mediastinitis in the treatment group (19%) versus 0% in the control group (P = .02). Tacrolimus-sirolimus therapy was associated with a nearly 11-fold increased incidence of new-onset diabetes mellitus as well (P = .004). CONCLUSION: Tacrolimus, sirolimus, and steroids (following low-dose rabbit antithymocyte globulin) were associated with an increased incidence of mediastinitis and posttransplantation diabetes mellitus. No obvious long-term benefit on survival, arteriopathy, or renal function was noted.

Study of the analgesic effect of lanepitant in patients with osteoarthritis pain.

OBJECTIVE: Lanepitant selectively blocks substance P binding to the neurokinin-1 receptor, preventing neurogenic inflammation and pain transmission. Substance P is present in synovial fluid and in excess in cerebral spinal fluid. We investigated the effect of lanepitant on pain caused by osteoarthritis to evaluate the role of neurokinin-1 blockade. METHODS: Outpatients (n = 214) with moderate to severe lower-limb osteoarthritis pain were treated for 3 weeks in a parallel, randomized double-blind study with initial doses of 20, 60, 200, or 600 mg lanepitant, 375 mg naproxen, or placebo, followed by 10, 30, 100, or 300 mg lanepitant twice a day, 375 mg naproxen twice a day, or placebo twice a day in the multiple-dose period. Pain intensity, pain relief, patient global impression, and adjunctive analgesic use were compared across treatments. Safety was evaluated with adverse events, vital signs, and laboratory assessments. RESULTS: There was no statistically significant difference in efficacy or safety across treatments for the initial dose assessment. After 1 week of therapy, naproxen was statistically significantly (P < .05) better than placebo and lanepitant in reducing average pain. During the second and third weeks of therapy, patients receiving naproxen continued to have statistically significantly (P < .05) less pain than those receiving placebo or lanepitant despite using significantly less adjunctive analgesic medication. There were no statistically significant differences in rates of discontinuation across treatments. Lanepitant treatment was associated with diarrhea, whereas naproxen treatment was associated with gastric discomfort. There were no clinically relevant changes in vital signs or laboratory analytes for any of the treatments. CONCLUSION: Lanepitant was ineffective in relieving osteoarthritis pain, possibly because neurokinin-1 binding of substance P does not play a significant role in osteoarthritis pain or because lanepitant fails to adequately penetrate the blood-brain barrier to affect central pain perception.

Long-term weight loss: the effect of pharmacologic agents.

We reviewed 20 English-language weight-reduction studies, reported between 1967 and March 1993, of the effect of > or = 6 mo of pharmacologic therapy on weight loss and its maintenance to determine the clinical benefits of extended treatment, propose treatment guidelines, and identify future research needs. Pharmacologic agents included phentermine, mazindol, fenfluramine, dexfenfluramine, and fluoxetine. Study designs varied with respect to blinding, use of a single agent vs a combination, dosing, length of therapy, patient selection, adjunctive therapy, and visit frequency. At endpoint, weight loss varied from study to study but a plateauing of weight loss or weight regain was observed after approximately 6 mo. The benefits of extended treatment appear to outweigh the risks for those patients who are unable to lose sufficient weight without pharmacologic therapy but who maintain adequate weight loss with long-term pharmacologic therapy. Future studies should define and evaluate pharmacologically responsive and unresponsive subgroups.

Treatment of cardiac tumors by orthotopic cardiac transplantation.

Primary soft tissue tumors of the heart usually cannot be excised with adequate margins. Orthotopic heart transplantation (OHT) could allow complete resection of cardiac tumors and has been performed in selected patients. However, most are not transplanted because of the high risk of tumor recurrence or metastasis and the possible enhancement of tumor growth by immunosuppressive drugs. Six patients with soft tissue cardiac tumors have been transplanted at the Columbia Presbyterian Medical Center: one paraganglionoma and one fibroma (both benign), and four malignant primary sarcomas. In all cases, there was no preoperative evidence of metastasis. In all but one case, the tumor was completely resected with adequate margins at the time of transplantation. One sarcoma patient who had not received preoperative or postoperative chemotherapy died suddenly 2.6 months after operation with no evidence of tumor. One patient is alive at 38 months with diffuse metastatic disease; two patients were treated preoperatively with intensive doxorubicin-based chemotherapy (one of whom also received postoperative external-beam radiotherapy to a positive surgical margin) and are tumor free 16 and 6 months after transplantation. Our experience compares favorably with the worldwide results of OHT for cardiac tumors (an additional 13 patients).

Cyclosporine-associated end-stage nephropathy after cardiac transplantation: incidence and progression.

BACKGROUND: The salutary immunosuppressive effects of cyclosporine in extending cardiac allograft survival may be curtailed by its nephrotoxic effects. We reviewed our first 9 years of experience with cyclosporine after cardiac transplantation, to evaluate the incidence and progression of cyclosporine-associated end-stage renal failure necessitating chronic hemodialysis. METHODS: Retrospective computer-based file review and personal interview when possible. RESULTS: The population at risk was comprised of all adult cardiac recipients surviving at least 3 years (n=293). Of these, 19 (6.5%) developed end-stage renal failure requiring chronic hemodialysis. There were 17 men and 2 women (mean age of 45 +/- 11 years). The mean creatinine clearance for the study group decreased by 38% (P<0.001 vs. before transplant) by 6 months after transplantation and by 48% by 3 years postoperatively (P<0.001 vs. before transplant). The mean serum creatinine rose by 80% (P< 0.001 vs. before transplant) by 6 months after transplantation and by 125% by 3 years postoperatively (P<0.001 vs. before transplant). Time elapsed from transplantation to hemodialysis ranged from 3.7 to 9.5 years (mean 6.4 +/- 2). Actuarial 1- year survival after onset of hemodialysis was 75%. CONCLUSIONS: Although cyclosporine remains the central immunosuppressive agent for cardiac allograft recipients, its use leads to a greater than one-third decrease in creatinine clearance by 6 months after transplantation and progression to end-stage renal failure, requiring hemodialysis in 6.5% of cardiac transplant recipients. Moreover, these patients are at increased risk of death compared with other cardiac allograft recipients. This data warrants the search of alternative or adjunctive agents that would allow decreased dosing or reduced nephrotoxicity of cyclosporine, while maintaining equivalent survival.

Carcinoma of the lung after heart transplantation.

We have recently noted an unexpected high incidence of lung cancer in our population of cardiac allograft recipients. We conducted a retrospective review of cardiac transplantation at our institution to investigate the incidence, clinical course, and outcome of patients who developed lung cancer following heart transplantation. Nine patients--each with a history of smoking at 30 pack-years--developed lung cancer following heart transplantation, for an incidence of 1.56% of patients at risk. Eight of the patients were male > or = 50 years of age, representing 3.3% of the male transplant recipients in this age group. The interval from transplantation to diagnosis clustered around 3-5 years after transplantation, but in two instances (22%), a neoplasm was discovered within 6 months of transplantation. Almost half of the cancers were discovered incidentally, despite routine radiographic surveillance. Seven of 9 (78%) patients had stage IV disease at presentation. Median survival after diagnosis was 3 months, and five of the seven patients who died survived less than 4 months after diagnosis. We conclude that cardiac transplant recipients are at increased risk for development of lung cancer. Patients with a moderate to heavy smoking history might well be advised to undergo chest CT scanning in an aggressive search for occult lung cancer before cardiac transplantation is considered further. Finally, despite frequent radiologic examinations, these lung cancers are often diagnosed incidentally, are far advanced at the time of diagnosis, are not surgically resectable, and are poorly responsive to adjuvant therapy.

Scanning microdensitometry of objects small relative to the wavelength of light.

Diffraction effects may have to be taken into account in microdensitometry when dealing with relatively dark specimens even an order of magnitude larger than the wavelength of light, and become progressively more important with smaller objects. According to geometrical optical theory, when scanning across the straight edge of a uniformly absorbing, semi-infinite object the distribution error per scan line is directly proportional to the diameter of the measuring-spot. Diffraction theory predicts similar results for measuring-spots larger than about 3 times the wavelength of light, but a significant error per scan line with very small or even infinitesimal measuring-spots. Diffraction theory further indicates that point absorbance measurements can be 95 + % accurate in the centers of 6.25, 2.5, and 2.0 microns diameter disks with absorbances respectively up to about 1.0, 0.39, and 0.25, but that this accuracy is unattainable with any object less than 1.25 microns in diameter. Scanning, integrating absorbance measurements are of somewhat lower accuracy than central point measurements with relatively large objects, e.g., they are only about 89% accurate with a 6 micron diameter object of absorbance 1.0. With very small objects, diffraction theory shows distribution error to be almost independent of the size of the scanning spot, and with an object of less than about 0.125 micron diameter the apparent integrated absorbance predicted by diffraction theory is effectively identical with that predicted by geometrical theory for an infinitesimal object scanned with a finite measuring-spot, i.e., it is the product of the object area and 0.4343 (1-It), where It is the true transmission. Scanning microdensitometry of objects of very low true absorbance is effectively free from distribution error. In practice, distribution error can be reduced by using an off-peak wavelength, by reducing the area illuminated, and by routine measurement and offsetting of apparent glare (some of which is actually due to diffraction). Little or nothing is to be gained by using a measuring-spot smaller than about one-quarter the wavelength of light.

Microimmunoassay permits determination of concentrations in immunohistochemistry controls.

A competition enzyme-linked immunosorbant assay (CELIA) can be used to determine the amount of antigen needed to immunoabsorb an antiserum. This is demonstrated using both polyclonal and monoclonal antibodies against human amylase. This method is of especial value when the tissue is particularly difficult to obtain, and especially valuable when CELIA has already been completed.

Serum bilirubin levels, intracranial hemorrhage, and the risk of developmental problems in very low birth weight neonates.

To study whether elevated levels of bilirubin in the neonatal period increase the risk of developmental problems for very low birth weight neonates, the investigators used data from a geographically based sample of 495 very low birth weight neonates, born January 1, 1985, to December 31, 1989, who survived to 1 year of adjusted age. Maximum neonatal bilirubin levels were found in medical records. A developmental problem was defined as either cerebral palsy or a Bayley Mental Developmental Index of less than 68 at 1 year adjusted age. Potentially confounding factors were controlled using logistic regression. To control for the effects of intracranial abnormalities (eg, intraventricular hemorrhage), separate logistic regression analyses were carried out for three strata, defined according to the results of cranial ultrasonography. In these analyses, the following odds ratios (with 95% confidence limits) were found for the association of maximum neonatal bilirubin concentration and developmental problems: for subjects without intracranial abnormalities, 0.9 (0.7, 1.9); for subjects with uncomplicated intracranial hemorrhage, 1.5 (0.8, 2.5); for subjects with complicated intracranial hemorrhage or intraparenchymal echo-densities, 1.2 (0.4, 3.6). In summary, in analyses controlled for confounding factors, maximum neonatal bilirubin level was not consistently associated with the risk of developmental problems identifiable at 1 year.

Randomized placebo-controlled trial of a 42-day tapering course of dexamethasone to reduce the duration of ventilator dependency in very low birth weight infants: outcome of study participants at 1-year adjusted age.

OBJECTIVE: Ventilator-dependent preterm infants are often treated with a prolonged tapering course of dexamethasone to decrease the risk and severity of chronic lung disease. The objective of this study was to assess the effect of this therapy on developmental outcome at 1 year of age. METHODS: Study participants were 118 very low birth weight infants who, at 15 to 25 days of life, were not weaning from assisted ventilation and were then enrolled in a randomized, placebo-controlled, double-blind trial of a 42-day tapering course of dexamethasone. Infants were examined at 1 year of age, adjusted for prematurity, by a pediatrician and a child psychologist. A physical and neurologic examination was performed, and the Bayley Scales of Infant Development were administered. All examiners were blind to treatment group. RESULTS: Groups were similar in terms of birth weight, gestational age, gender, and race. A higher percentage of dexamethasone recipients had major intracranial abnormalities diagnosed by ultrasonography (21% vs 11%). Group differences were not found for Bayley Mental Development Index (median [range] for dexamethasone-treated group, 94 [50-123]; for placebo group, 90 [28-117]) or Psychomotor Development Index Index (median [range]) for dexamethasone-treated group, 78 (50-109); for placebo-treated group, 81 [28-117]). More dexamethasone-treated infants had cerebral palsy (25% vs 7%) and abnormal neurologic examination findings (45% vs 16%). In stratified analyses, adjusted for major cranial ultrasound abnormalities, these associations persisted (OR values for cerebral palsy, 5.3; 95% CI: 1.3-21.4; OR values for neurologic abnormality 3.6; 95% CI: 1.2-11.0). CONCLUSIONS: A 42-day tapering course of dexamethasone was associated with an increased risk of cerebral palsy. Possible explanations include an adverse effect of this therapy on brain development and/or improved survival of infants who either already have neurologic injury or who are at increased risk for such injury.

Interaction of angiotensin II with the cholinergic and noradrenergic systems in the rat pineal gland: regulation of indole metabolism.

The pineal gland, angiotensin, and noradrenergic and cholinergic systems are involved in the regulation of tissue indole metabolism. Angiotensin II increased noradrenaline release and the production of hydroxy- and methoxyindoles by pineal slices. Electrical field stimulation (EFS) of pineal slices released angiotensin II and reproduced many of the actions of exogenous angiotensin II on serotonin and melatonin biosynthesis and release. Both sarcosine-isoleucine-angiotensin II ([Sar, Ile]-ANG II) and atropine blocked, and nadolol increased, the effect of EFS and exogenous angiotensin II on serotonin production. Nadolol blocked both the EFS-induced and the angiotensin II-induced production of melatonin. Atropine and [Sar, Ile]-ANG II did not modify melatonin biosynthesis in electrically stimulated slices, but the muscarinic receptor antagonist increased the stimulatory effect of angiotensin II. These data showed that EFS released angiotensin II and noradrenaline from pineal slices and that a close functional connection exists between the peptide and acetylcholine. The stimulation of serotonin biosynthesis and release by these two neurotransmitters was negatively regulated by noradrenaline acting through beta-adrenergic receptors.

Nager acrofacial dysostosis: evidence for apparent heterogeneity.

Nager acrofacial dysostosis is characterized by malar, mandibular, and maxillary hypoplasia, macrostomia, abnormal ears, and radial defects. The lower limbs are usually normal. Two patients were reported with many of these manifestations, in addition to severe facial clefts and limb deficiency. These more severely affected patients were thought to have a severe form of Nager acrofacial dysostosis or a new syndrome. We report on a patient with limb findings of intermediate severity. This patient also had hydrocephalus, micropolygyria, and tetralogy of Fallot. This may indicate apparent heterogeneity or a single condition with widely variable expression.