[Frame-less and frame-based stereotaxy? How to choose the appropriate procedure]

In recent years, additional tools for image guided surgery have been developed. Devices are now available for frameless punction and biopsy of intracerebral lesions and the indications for frameless and frame-based stereotaxy are increasingly overlapping. The objective of our paper was to analyse the most important factors that influence the decision on when to use frameless and when frame-based stereotaxy. Criteria such as application accuracy, image information and ergonomics were investigated for different lesions. Frameless and frame-based stereotaxy are complementary systems with different indications. They are different in terms of image information and ergonomics. Image guided surgery is the standard for continuous 3-dimensional topographical orientation. With high quality images (1 mm slice thickness) and bone marker registration, frameless stereotaxy may achieve an application accuracy comparable to frame-based systems. However, when using adhaesively mounted skin fiducials for patient registration, frameless stereotaxy is less accurate than framebased systems. Therefore, the size of the lesion should exceed 10 mm for punction and biopsy with a frameless system. Frame-based stereotaxy remains the gold standard for accurate targeting of lesions < 10 mm and for functional procedures.

Role of in vitro cholesterol depletion in mediating human platelet aggregation

We investigated the direct role of cholesterol lowering on human platelet aggregation by in vitro cholesterol depletion using methyl-beta-cyclodextrin. Collagen and thrombin receptor agonist peptide induced maximal aggregation was significantly decreased in cholesterol depleted platelets. In contrast, anti-CD9 antibody, mAb7, or anti-beta(3) antibody, D3, induced percent maximal aggregation was unaffected by cholesterol depletion. Surface and total alpha(IIb)beta(3) levels were equivalent in both groups. Morphological and ultrastructural analysis of collagen induced aggregates revealed that normal and cholesterol depleted platelets changed shape and aggregated; however, cholesterol depletion impaired microtubule ring formation and aggregate size. Cholesterol depletion also diminished the extent of the open canalicular system and collagen induced platelet ATP release. These data suggest cholesterol depletion impairs platelet aggregation by altering platelet ultrastructure critical in mediating secretion. Temporal differences and differences in tyrosine phosphoprotein levels following collagen stimulation were observed, thereby indicating that platelet signaling was concurrently affected by cholesterol depletion.

Clinical experience with substance P receptor (NK1) antagonists in depression

Substance P (SP) belongs to the neurokinin (NK) family of neuropeptides and exerts its biological effects via interaction with the NK1 receptor. The SP-NK1 receptor system is one of the best-characterized neurotransmitter pathways in both the central and peripheral nervous systems. It has been postulated that this pathway may have important roles in a variety of centrally regulated pathophysiologic conditions, including depression. In animal models, central injection of SP was associated with a series of anxiety-like behaviors, and this response could be abolished by pretreatment with SP (NK1) receptor antagonists (SPAs). On the basis of these and other encouraging preclinical results, several clinical trials have examined the potential of SPAs in the treatment of depression. In phase 2 trials, therapy with the SPAs aprepitant (MK-0869) and compound A resulted in improvements in depression and anxiety symptoms that were quantitatively comparable with those seen with selective serotonin reuptake inhibitors (SSRIs) and significantly greater than those seen with placebo. These positive results have established a proof of concept that the inhibition of the SP-NK1 receptor pathway may be a potentially useful novel treatment option for management of patients with depression. The apparent lack of benefit with SPAs versus placebo in subsequent dose-finding studies with aprepitant and compound A is not surprising, considering the fact that the outcomes with an active control (SSRI) in these trials were also similar to those observed with placebo. Future trials with SPAs will focus on the identification of appropriate patients and drug regimens and will also define the role of these agents in the treatment of depression.

Expression of interleukin-18, interferon-gamma and interleukin-10 in hepatocellular carcinoma

This is the first report on the detection of IL-18, IFN-gamma and IL-10 proteins in hepatocelllular carcinoma. In the apparently normal surrounding tissue, 13 out of 17 paired specimens showed positive immunoreactivity to IL-18 (76.5%) compared with six out of 17 in the tumour portion (35.3% of specimens). Thus, a significantly higher number of IL-18 positive specimens was found in the hepatocytes of apparently normal surrounding tissue compared with the tumour (P=0.018). In contrast, the number of specimens with positive immunoreactivity to the antibody against the Th1 cytokine, IFN-gamma expression in the hepatocytes was lower. Only one specimen from the apparently normal surrounding tissue (one out of 17; 5.9%) and three other specimens from the tumour portion (three out of 17; 17.6%) had positive immunoreactivity. Similarly, the expression of the Th2 cytokine, IL-10 in normal (four out of 17; 23.5%) and tumour portions (five out of 17; 29.4%) was also low. Thus, there did not appear to be predominant Th2 immune response as denoted by IL-10 expression. Using the Spearman correlation rank test, a significant correlation between IL-18 expression in the apparently normal surrounding tissue and high alpha-foetoprotein (AFP) levels of >350 IU/l. No correlation between IL-18 expression in the tumour portion and clinicopathological factors was found. There was also no correlation found between IL-18 and the other cytokines, namely, IFN-gamma and IL-10 expression These new findings provide additional information on the type of cytokines expressed in the tumour microenvironment and give a further insight into the role of cytokines in the pathogenesis of cancer which is critical for the development of effective immunotherapeutic approaches for cancer therapy in the future.

Cervical necrotising fasciitis consequent to mastoid infection

We present a case of cervical necrotising fasciitis in a 56 year old man, secondary to a rare mastoid infection. The patient had coexisting diabetes mellitus and hypertension. He was treated with early surgical debridement followed by neck and chest reconstruction and radical mastoidectomy. Aggressive antibiotic therapy and supportive care was given. He recovered well with minimal residual functional deficit.

A role for the angiotensin AT4 receptor subtype in overcoming scopolamine-induced spatial memory deficits

There is increasing interest in the role of the brain angiotensin AT4 receptor subtype in cognitive processing. This receptor subtype is activated by angiotensin IV (AngIV), is heavily distributed in the mammalian hippocampus, neocortex, and cerebellum, and has been linked with a learning and memory function. The present investigation utilized intracerebroventricular (i.c.v.)-infused scopolamine hydrobromide (scop), a muscarinic receptor antagonist, to disrupt acquisition of the circular water maze task of spatial memory. All animals received 2 days of training trials (five trials/day) using a visible platform in an effort to preclude subsequent confounding by scopolamine-induced sensory and/or motor impairments. In the first experiment, i.c.v.-infused scopolamine (70 nmol) was followed by 0, 10, 100, or 1000 pmol i.c.v. doses of Nle(1)-AngIV in separate groups of rats. Results indicated that each dose of Nle(1)-AngIV improved the poor acquisition of this task induced by scopolamine treatment. However, the 100- and 1000-pmol doses were most effective with respect to latency and distance to find the submerged pedestal. A second experiment demonstrated that treatment with a specific AT4 receptor antagonist, Nle(1), Leual(3)-AngIV (1000 pmol), blocked the ability of Nle(1)-AngIV (100 pmol) to improve the performance of scopolamine-compromised rats. These results support the notion that hippocampal AT4 receptors are involved in spatial memory processing, and that activation of these binding sites can overcome the disruption of spatial memory accompanying treatment with a muscarinic receptor antagonist.

Human myeloid dendritic cells transduced with an adenoviral interleukin-10 gene construct inhibit human skin graft rejection in humanized NOD-scid chimeric mice

Human myeloid DC were generated from peripheral blood mononuclear cells by monocyte adhesion and subsequent culture with rhGM-CSF and rhIL-4. We transduced immature (day 5 of culture) myeloid DC with an E1-deleted replication-deficient adenoviral vector encoding the cytokine IL-10 (AdV IL-10) and a control adenovirus MX-17 (AdV MX 17). Human DC transduced with AdV IL-10 showed inhibition of the mixed leukocyte culture, reduced cell surface expression of co-stimulatory molecules (CD80/CD86) and were unable to produce the potent allo-stimulatory cytokine, interleukin-12. In order to test the in vivo properties of these cells a humanized immunodeficient mouse skin transplantation model was developed. Immunodeficient NOD-scid mice were engrafted with human skin, reconstituted via intraperitoneal injection with allogeneic mononuclear cells (MNC) mixed with 1 x 10(6) DC that were autologous to the skin donor and that had been transduced with either AdV IL-10 or AdV MX-17. Skin grafts were removed at day 7 and 14 after reconstitution and studied histologically for evidence of rejection. In animals that received DC modified with AdV IL-10 there was reduced skin graft rejection as characterized by reduced mononuclear cell infiltration and less dermo-epidermal junction destruction compared with those animals that received DC modified with the control virus alone. Injection of equivalent numbers of donor-derived fibroblasts transduced with AdV IL-10 were ineffective at modifying rejection of skin grafts. Immunosuppressive cytokine gene therapy targeting human DC is a novel means of inhibition of the alloimmune response.

Human immunodeficiency virus-infected patients receiving highly active antiretroviral therapy maintain activated CD8+ T cell subsets as a strong adaptive immune response to cytomegalovirus

CD8(+) T lymphocyte function specific for human cytomegalovirus (CMV) was evaluated in 14 patients infected with human immunodeficiency virus (HIV) receiving highly active antiretroviral therapy (HAART) and 26 CMV-seropositive donors without HIV infection. Fifty-seven percent of the HIV-infected group had CMV-specific cytolytic activity in freshly isolated peripheral blood mononuclear cells (PBMC) against targets expressing CMV pp65. Both interferon (IFN)-gamma secretion by CD8(+) T cells and the frequency of human leukocyte antigen (HLA)-tetramer-positive T cells in HLA-A*0201-positive HIV-infected subjects correlated with CMV-specific cytolysis. In contrast, PBMC from healthy CMV-seropositive donors did not have either measurable CMV-specific cytolysis or secretion of IFN-gamma without in vitro stimulation. The T helper response to CMV antigens was vigorous in healthy CMV-seropositive donors but low in the cohort of HIV-infected patients. Potent CD8(+) cytotoxic T lymphocyte responses to CMV in HIV-infected patients receiving HAART is the converse of what is found in healthy CMV-seropositive subjects and may be the predominant adaptive immune response against CMV in HIV-infected patients.

A comparison of dermal and cadaveric pericardial grafts in the modified Horton-Devine procedure for Peyronie's disease

PURPOSE

Penile curvature due to Peyronie's disease is often treated with plaque incision or excision and grafting. The advantages of various graft materials have long been debated. We studied the outcomes of dermal and cadaveric pericardial grafts after plaque incision or excision for Peyronie's disease.

MATERIALS AND METHODS

We retrospectively evaluated all modified Horton-Devine procedures performed between February 1998 and April 2000. Dermal graft harvested from the lower abdomen or commercially available cadaveric pericardium was used to cover the corporeal defect. A followup telephone questionnaire was administered to determine patient satisfaction and function.

RESULTS

We reviewed the records of 27 men, including 18 and 9 who received a dermal and pericardial graft, respectively. We successfully contacted 24 patients, including 15 with a dermal and 9 with a pericardial graft, to evaluate satisfaction. Average postoperative followup was 10 months. Of the 24 patients, 22 reported successful coitus and 15 (63%) needed assistance to achieve erection rigid enough for satisfactory coitus. Eight patients reported recurrent curvature, which was minimal and did not hamper sexual function. Overall 11 of the 15 patients with a dermal and 8 of the 9 with a pericardial graft would undergo the surgery again or recommend it to others.

CONCLUSIONS

The results of the dermal and cadaveric pericardial grafts were comparable. The minimal preoperative preparation, decreased patient morbidity and pliability of cadaveric pericardium make it an attractive suitable graft substitute in the modified Horton-Devine procedure. Longer followup and larger patient series are needed to confirm the advantages of cadaveric pericardium.

Pigmented Bowen's disease (squamous cell carcinoma in situ): a mimic of malignant melanoma

BACKGROUND

Darkly pigmented individuals may manifest unusual or uncharacteristic presentations of various skin conditions, including heavy pigmentation of cutaneous tumors.

OBJECTIVE

To increase the awareness of an unusual presentation of Bowen's disease in a darkly pigmented individual.

METHODS

We report the case of a 52 year old black woman that presented with a lesion clinically consistent with malignant melanoma. However, histopathologic examination revealed pigmented Bowen's disease.

RESULTS

A biopsy is almost always indicated to confirm the diagnosis of lesions in darkly pigmented individuals.

CONCLUSION

This case is presented to reinforce the idea that pigmented Bowen's disease should be considered in the differential diagnosis of malignant melanoma.

Prolongation of sheep corneal allograft survival by ex vivo transfer of the gene encoding interleukin-10

BACKGROUND

Modification of a donor cornea by gene therapy ex vivo has potential to modulate irreversible rejection, the major cause of corneal graft failure. Our aim was to transfer the gene encoding mammalian IL-10 to ovine donor corneas and to determine subsequent orthotopic corneal allograft survival in an outbred sheep model.

METHODS

The replicative capacity of ovine corneal endothelium was determined by autoradiography after deliberate injury. A replication-defective adenovirus was used to deliver the lacZ reporter gene to ovine corneas and transfected corneas were organ-cultured in vitro to allow transfection efficiency, duration of reporter gene expression, and toxicity attributable to the vector to be determined. A cDNA encoding full-length ovine IL-10 was cloned into an adenoviral vector that was used to transfect donor corneas ex vivo before transplantation. Orthotopic penetrating corneal transplantation was performed in outbred sheep.

RESULTS

Sheep corneal endothelium was found to be essentially amitotic. Transfection of > 70% corneal endothelial cells was achieved with the viral vector and expression was maintained for 28 days in vitro. IL-10 mRNA was detectable in transfected, organ-cultured corneas for 21 days in vitro. Donor corneas transfected with cDNA encoding IL-10 showed significantly prolonged survival after penetrating keratoplasty (median 55 days, range 19 > or =300 days) compared with control corneas (median 20.5 days, range 18-32 days, P=0.011).

CONCLUSION

Local gene therapy-mediated expression of the immunomodulatory cytokine IL-10 has the potential to reduce the incidence of corneal graft rejection and to prolong corneal allograft survival.

Enhanced immune activity of cytotoxic T-lymphocyte epitope analogs derived from positional scanning synthetic combinatorial libraries

The pp65(495-503) cytotoxic T-lymphocyte (CTL) epitope from cytomegalovirus (CMV) is universally recognized among CMV+ individuals who express an allele of the human leukocyte antigen A (HLA-A*0201). The relative binding affinity of the epitope to HLA-A*0201 is moderate, and its increased activity might prove beneficial in its use as a CTL epitope vaccine. A new approach to enhance the activity of T-cell epitopes is the use of positional scanning synthetic combinatorial libraries (PS-SCLs). Using a nonamer PS-SCL, the pp65(495-503) epitope was modified after screening a CMV-specific T-cell clone (TCC) (3-3F4) from which the native peptide sequence was derived. Two peptides with amino acid substitutions at P1, P3, P7, and P8 are between 10(3) and 10(4) more active than the native epitope. Although the native CTL epitope terminates as a free acid, both tetrasubstituted peptides only function as CTL epitopes when the carboxyl terminus is amidated. Selective substitution of the native sequence based on PS-SCL screening results identified 3 amidated monosubstituted and disubstituted peptides that are better recognized than the native epitope by TCCs from a cohort expressing HLA-A*0201. In vitro stimulation of peripheral blood mononuclear cells with each of the peptide epitope analogs stimulated memory CTLs, which recognized CMV-infected targets among a high percentage of CMV+ individuals. Binding studies of peptide analogs with HLA-Ig (immunoglobulin) dimers and 2 different TCCs correlated with in vitro lysis results. These data suggest that increasing the activity of CTL epitopes while maintaining broad recognition is possible, which holds promise for vaccine development in infectious disease and cancer.

Population coverage by HLA class-I restricted cytotoxic T-lymphocyte epitopes

Vaccination using cytotoxic T-lymphocyte (CTL) epitopes has become a widely used immunization strategy, especially because their structure makes them an attractive alternative to the delivery of whole proteins as immunogens. Nonetheless, their use is limited, in particular because of their specificity, being recognized only by cognate HLA alleles. The potential for immunizing a substantial portion of an ethnically diverse population using a modest number of peptides has been aided by the identification of HLA supertypes. However, the derivation of epitopes is often guided by methods that do not guarantee cross-reactivity, so we consider the feasibility of providing vaccine coverage to a multi-ethnic population under different assumptions. In particular, two large datasets are used to estimate the number of peptides needed to provide > or =90% group-specific coverage of a multiethnic population, when specificity is assumed to be either to a single serologic or molecular type. These assumptions are evaluated utilizing a clinically important epitope repertoire derived from two human cytomegalovirus proteins, and data on the in vitro memory response elicited by these peptides is presented. In summary, our combined theoretical and empiric studies suggest that 90% coverage of some ethnic groups is attainable with 11 uniquely defined HLA-restricted CTL epitopes. The derivation of four or more additional CTL epitopes is needed to attain 90% coverage of Blacks or Asians, the minimally covered groups. Ninety percent coverage of all major ethnic groups in a multi-ethnic population appears feasible without relying on cross-reactivity, but may require two to three times more CTL epitopes than estimated for serologic data, homogenous populations, or HLA alleles grouped as supertypes.