Efficacy of reverse transcriptase-polymerase chain reaction screening for micrometastic disease in axillary lymph nodes of breast cancer patients

Pathologic examination of axillary lymph nodes (ALNs) may miss micrometastases in 30 per cent of breast cancer patients. We have developed a multimarker reverse transcriptase-polymerase chain reaction (RT-PCR)-based screening method that detects histopathologically positive ALNs with a 5 per cent false-negative rate. The purpose of this study was to compare this RT-PCR methodology with histopathology with regard to sensitivity and cost. Pathologically negative ALNs from 35 breast cancer patients were re-evaluated by a single pathologist in a blinded fashion using serial sectioning with immunohistochemical staining. Histopathologic results were then compared with those of RT-PCR. Cost analysis was performed based on standard charges for these methods. RT-PCR identified micrometastases in 14 of 35 pathologically negative nodes. Serial sectioning and immunohistochemical staining identified micrometastases in two cases, with RT-PCR positive for one of these. The charge per specimen for performing routine histopathologic examination was $380, serial sectioning and immunohistochemical staining $787, and RT-PCR $125. RT-PCR appears to be more sensitive at detecting ALN micrometastasis than histopathologic examination even with serial sectioning and immunohistochemical staining. If micrometastatic breast cancer detected by RT-PCR proves to be clinically relevant, it could be a more effective screening methodology with significant cost savings as compared to currently available pathologic examinations.

Glutathione-mediated detoxification systems in plants

Recent work has highlighted the presence of diverse glutathione-dependent enzymes in plants with potential roles in the detoxification of both xenobiotic and endogenous compounds. In particular, studies on glutathione transferases are further characterising their role in xenobiotic metabolism, and also raising intriguing possible roles in endogenous metabolism. The solution of their three-dimensional structures together with studies on their molecular diversity and substrate specificity is providing new insights into the function and classification of these enigmatic enzymes.

Core and penumbral nitric oxide synthase activity during cerebral ischemia and reperfusion

BACKGROUND AND PURPOSE

The present studies examined the hypothesis that the distribution of cerebral injury after a focal ischemic insult is associated with the regional distribution of nitric oxide synthase (NOS) activity.

METHODS

Based on previous studies that certain anatomically well-defined areas are prone to become either core or penumbra after middle cerebral artery occlusion (MCAO), we measured NOS activity in these areas from the right and left hemispheres in a spontaneously hypertensive rat filament model. Four groups were studied: (1) controls (immediate decapitation); (2) 1.5 hours of MCAO with no reperfusion (R0); (3) 1.5 hours of MCAO with 0.5 hour of reperfusion (R0.5); and (4) 1.5 hours of MCAO with 24 hours of reperfusion (R24). Three groups of corresponding isoflurane sham controls were also included: 1.5 (S1.5) or 2 (S2.0) hours of anesthesia and 1.5 hours of anesthesia+24 hours of observation (S24).

RESULTS

Control core NOS activity for combined right and left hemispheres was 129% greater than penumbral NOS activity (P<0.05). Combined core NOS activity was also greater (P<0.05) in the three sham groups: 208%, 122%, and 161%, respectively. In the three MCAO groups, ischemic and nonischemic core NOS remained higher than penumbral regions (P<0.05). However, NOS activity was lower in the ischemic than in the nonischemic core in all three groups: R0 (29% lower), R0.5 (48%), and R24 (86%) (P<0.05). Addition of cofactors (10 micromol/L tetrahydrobiopterin, 3 micromol/L flavin adenine dinucleotide, and 3 micromol/L flavin mononucleotide) increased NOS activity in all groups and lessened the decrease in ischemic core and penumbral NOS.

CONCLUSIONS

Greater NOS activity in core regions could explain in part the increased vulnerability of that region to ischemia and could theoretically contribute to the progression of the infarct over time. The data also suggest that NOS activity during ischemia and reperfusion could be influenced by the availability of cofactors.

The effect of the reduction of colloid oncotic pressure, with and without reduction of osmolality, on post-traumatic cerebral edema

BACKGROUND

It has been asserted that reduction of colloid oncotic pressure (COP) can aggravate traumatic brain edema. To explore this issue, the authors measured the effect of COP reduction, with and without a simultaneous decrease in osmolality, on the development of brain edema after fluid percussion injury (FPI).

METHODS

Isoflurane-anesthetized Wistar rats received a 2.7-atm right parasagittal FPI followed by isovolemic exchange with (1) normal saline (NS); (2) half-normal saline (0.5 NS); (3) whole blood (WB); or (4) hetastarch (Hespan, Dupont). Shed blood (16 ml) was replaced with donor erythrocytes suspended in the study fluid. The WB group received heparinized fresh donor WB. Central venous pressure was maintained with additional study fluid as required. The specific gravity (SG) of the cortex and subcortex near the impact site was determined 4.5 h after FPI. The water content of the hemispheres was also determined using the wet-dry method. To define the status of the blood-brain barrier in the non-FPI hemisphere, two additional groups (FPI, non-FPI) were studied. Both groups received 30 mg/kg Evans' blue and NS at 4 ml/kg(-1)/h(-1). Four hours after FPI, the concentration of Evans' blue in the hemispheres was determined.

RESULTS

After exchange, COP (mmHg +/- SD) decreased in the NS (9.6 +/- 2.1) and 0.5 NS (8.5 +/- 0.5) groups and was unchanged in the WB (16.7 +/- 3.3) and hetastarch (18.9 +/- 1.1) groups. Osmolality was unchanged in the WB group (295 +/- 5 mOsm/kg), increased in the NS (304 +/- 3 mOsm/kg) and hetastarch (306 +/- 2 mOsm/kg) groups, and was decreased in the 0.5 NS group (261 +/- 6 mOsm/kg). The Evans' blue data indicated that FPI resulted in blood-brain barrier damage in both hemispheres. In all four exchange groups, the SG of both cortical and subcortical tissue was less (indicating greater water content) in the impact hemisphere than in the nonimpact hemisphere. The SG was less in both hemispheres, although it was less in both hemispheres in the NS and 0.5 NS groups than in the WB and hetastarch groups. The lowest SG values were observed in the 0.5 NS group. The wet-dry water content determinations yielded a similar pattern of edema formation.

CONCLUSIONS

These data, while confirming the important edematogenic effect of decreased osmolality, indicate that COP reduction per se can also aggravate brain edema after a mild to moderate mechanical head injury.

Isoflurane and pentobarbital reduce the frequency of transient ischemic depolarizations during focal ischemia in rats

Repetitive transient ischemic depolarizations (IDs) during focal cerebral ischemia are thought to contribute to ischemic damage. Isoflurane and pentobarbital reduce injury (versus the nonanesthetized state) after focal cerebral ischemia. The mechanism by which these drugs reduce injury is not known. This protective effect might be mediated by a reduction in the number of IDs. We measured the frequency of IDs during focal cerebral ischemia in animals anesthetized with isoflurane or pentobarbital and compared it with that in N2O/fentanyl anesthetized animals and in animals in which the N-methyl-D-aspartate receptor antagonist MK801 (dizocilpine) was given. Focal cerebral ischemia was induced by the occlusion of the middle cerebral artery for a period of 2 h. Cortical infarct volumes were determined after 3 h of reperfusion by image analysis of 2,3,5-triphenyl tetrazolium-stained coronal brain sections. The infarct volume was significantly greater in the N2O/fentanyl group than in the other three groups. Infarct volumes in the isoflurane, pentobarbital, and MK801 groups were similar. The frequency of IDs was significantly greater in the N2O/fentanyl group than in the other three groups, and was the least in the MK801 group. There was a direct correlation between the number of IDs and the volume of tissue injury. The data indicate that the protective effect of isoflurane and pentobarbital might, in part, be determined by their ability to reduce IDs during focal ischemia. However, the observation that the infarct volume was similar in the MK801, isoflurane, and pentobarbital groups, despite a greater frequency of IDs in the latter two groups, suggests that mechanisms other than a simple reduction in the number of IDs probably also play a role in anesthetic-mediated cerebral protection.

IMPLICATIONS

Transient ischemic depolarizations during focal ischemia contribute to brain injury. Both isoflurane and pentobarbital reduced the frequency of these depolarizations. Isoflurane- and pentobarbital-mediated reduction in the frequency of depolarizations might, in part, mediate the previously documented neuroprotective effect of these drugs.

Intrathoracic aberrant thyroid: identification critical for appropriate operative approach

True aberrant thyroid in the chest is a rarely described entity. More commonly, "aberrant" thyroid is a substernal goiter that is an extension of the cervical gland inferiorly and can be removed safely with the classic "collar" incision. Aberrant intrathoracic thyroid typically derives its blood supply from intrathoracic sources and requires an alternate surgical approach for adequate exposure. The ability to identify these rare intrathoracic thyroids is critical for safe surgical excision.

Purification, regulation and cloning of a glutathione transferase (GST) from maize resembling the auxin-inducible type-III GSTs

The glutathione transferases (GSTs) from maize (Zea mays L.) with activities toward the chloroacetanilide herbicide metolachlor and the diphenyl ether herbicide fluorodifen were fractionated into two pools based on binding to affinity columns. Pool 1 GSTs were retained on Orange A agarose and were identified as isoenzymes Zea mays (Zm) GST I-I, Zm GST I-II and Zm GST I-III, which have been described previously. Pool 2 GSTs selectively bound to S-hexyl-glutathione-Sepharose and were distinct from the pool 1 GSTs, being composed of a homodimer of 28.5 kDa subunits, termed Zm GST V-V, and a heterodimer of the 28.5 kDa polypeptide and a 27.5 kDa subunit, termed Zm GST V-VI. Using an antibody raised to Zm GST V-VI, a cDNA expression library was screened and a Zm GST V clone identified showing sequence similarity to the type-III auxin-inducible GSTs previously identified in tobacco and other dicotyledenous species. Recombinant Zm GST V-V showed high GST activity towards the diphenyl ether herbicide fluorodifen, detoxified toxic alkenal derivatives and reduced organic hydroperoxides. Antibodies raised to Zm GST I-II and Zm GST V-VI were used to monitor the expression of GST subunits in maize seedlings. Over a 24 h period the Zm GST I subunit was unresponsive to chemical treatment, while expression of Zm GST II was enhanced by auxins, herbicides, the herbicide safener dichlormid and glutathione. The Zm GST V subunit was more selective in its induction, only accumulating significantly in response to dichlormid treatment. During development Zm GST I and Zm GST V were expressed more in roots than in shoots, with Zm GST II expression limited to the roots.

Magnetic resonance cholangiopancreatography: a novel approach to the evaluation of suspected pancreaticobiliary neoplasms

BACKGROUND

Magnetic resonance cholangiopancreatography (MRCP) is a new noninvasive diagnostic method for pancreaticobiliary (PB) imaging without endoscopy, sedation, or iodinated contrast. The purpose of this study was to evaluate the ability of MRCP to depict pancreatic and biliary ductal anatomy compared to that of endoscopic retrograde cholangiopancreatography (ERCP) and to evaluate the ability of MRCP to accurately diagnose PB neoplasms.

METHODS

Twenty patients had MRCP, and 17 also had ERCP. All studies were read prospectively by experienced reviewers blinded to other imaging data. Pathologic diagnosis was made in all patients.

RESULTS

Bile duct dilatation seen by ERCP in 14 of 17 patients was correctly identified by MRCP in all 14 patients, and normal ducts were correctly identified by MRCP in the other 3 patients. The pancreatic duct was visible on MRCP in the pancreatic head in 17 of 20 patients, the body in 17 of 20 patients, and the tail in 15 of 20 patients. At ERCP, pancreatic duct dilatation was present in 11 cases and was identified by MRCP in 10 of them. Eighteen of 20 patients had malignant PB neoplasms. MRCP indicated PB neoplasm in 19 patients. Seventeen of these 19 patients had histologically confirmed malignant neoplasms pathologically, whereas 2 had benign pathology (both chronic pancreatitis). Among the 17 patients who also had ERCP, MRCP and ERCP correctly agreed on a final diagnosis of malignant neoplasm in 14 cases. In the three cases in which MRCP and ERCP disagreed on a final diagnosis, MRCP was correct in one and incorrect in two.

CONCLUSIONS

MRCP can accurately and noninvasively delineate PB ductal anatomy and diagnose PB neoplasms comparably to ERCP. MRCP is an interesting new noninvasive method for evaluating patients with suspected PB neoplasms.

Experimental subarachnoid hemorrhage in rats: effect of intravenous alpha-alpha diaspirin crosslinked hemoglobin on hypoperfusion and neuronal death

BACKGROUND

Hemodilution with diaspirin crosslinked hemoglobin (DCLHb) ameliorates occlusive cerebral ischemia. However, subarachnoid hemoglobin has been implicated as a cause of cerebral hypoperfusion. The effect of intravenous DCLHb on cerebral perfusion and neuronal death after experimental subarachnoid hemorrhage was evaluated.

METHODS

Rats (n = 48) were anesthetized with isoflurane and subarachnoid hemorrhage was induced by injecting 0.3 ml of autologous blood into the cistema magna. Each animal received one of the following regimens: Control, no hematocrit manipulation; DCLHb, hematocrit concentration decreased to 30% with DCLHb; or Alb, hematocrit concentration decreased to 30% with human serum albumin. The experiments had two parts, A and B. In part A, after 20 min, cerebral blood flow (CBF) was assessed with 14C-iodoantipyrine autoradiography. In part B, after 96 h, in separate animals, the number of dead neurons was determined in predetermined coronal sections by hematoxylin and eosin staining.

RESULTS

Cerebral blood flow was greater for the DCLHb group than for the control group; and CBF was greater for the Alb group than the other two groups (P < 0.05). In one section, CBF was 45.5 +/- 10.9 ml x 100 g(-1) x min(-1) (mean +/- SD) for the control group, 95.3 +/- 16.6 ml x 100 g(-1) x min(-1) for the DCLHb group, and 138.1 +/- 18.7 ml x 100 g(-1) x min(-1) for the Alb group. The number of dead neurons was less in the Alb group (611 +/- 84) than in the control group (1,097 +/- 211), and was less in the DCLHb group (305 +/- 38) than in the other two groups (P < 0.05).

CONCLUSIONS

These data support a hypothesis that hemodilution decreases hypoperfusion and neuronal death after subarachnoid hemorrhage. The data do not support the notion that intravascular molecular hemoglobin has an adverse effect on brain injury after subarachnoid hemorrhage.

T-cell receptor repertoire in matched MART-1 peptide-stimulated peripheral blood lymphocytes and tumor-infiltrating lymphocytes

Characterization of tumor-associated antigens (TAAs) recognized by CTLs makes the consideration of therapeutic strategies based on peptide stimulation of peripheral blood lymphocytes (PBLs) feasible. Several such approaches are adoptive transfer of peptide-stimulated PBLs, ex vivo peptide stimulation of dendritic cells, and direct vaccination with TAA-derived peptides. A critical component of any of these peptide-based strategies is the requirement that the patient's PBLs are able to react productively against the presented TAA. The purpose of this study, through the study of T-cell receptor (TCR) usage, was to evaluate the T-cell response in matched MART-1(27-35) peptide-stimulated PBLs and tumor-infiltrating lymphocytes (TILs). MART-1(27-35)-reactive PBL and TIL cultures were generated from three patients by in vitro stimulation with an immunodominant peptide of MART-1 (MART-1(27-35)). All cultures had a human leukocyte antigen A2-restricted, MART-1(27-35)-specific CTL response. The TCR usage of each was assessed by the DNA sequence analysis of 50 TCR beta clones obtained by rapid amplification of cDNA ends per culture. TCR analysis suggests a TCR repertoire that differed from patient to patient (8-16 subfamilies were used) and a predominant usage of a different variable beta chain (BV) by each of these MART-reactive T cells. These predominant BV rearrangements were derived from multiple clonotypes because different variable, diversity, and junctional regions were observed. However, a similar pattern of expansion was present for both PBLs and TILs; the relative usage of each prevailing BV was more marked in TILs (36, 50, and 78% of TILs versus 26, 20, and 24% of PBLs, respectively), a broader TCR repertoire was used by PBLs (P > 0.05), and similar TCR subfamily usage was noted when TIL and PBL cultures from the same patient were compared (8 of 11, 7 of 9, and 7 of 8 for patients 1, 2, and 3, respectively). Furthermore, the exact same clonotypes derived from predominant TCR subfamilies in the PBLs and TILs were present in each patient, suggesting peptide-stimulated expansion in both biological compartments. These studies suggest that there will not be a limited and predictable TCR subfamily response to a specific TAA, although reproducible patterns of PBL and TIL expansion are present from patient to patient. Additionally, identical T-cell clonotypes having the same potential for antigen-driven expansion were present in a patient's PBLs and TILs. As such, our data support the conceptualization of approaches using adoptive transfer or vaccination based on TAA-derived peptide stimulation of PBLs.

Stereotactic core biopsy of the breast: results of one-year follow-up of 101 patients

Stereotactic core biopsy (SCB) is being used as a cost-effective alternative to needle localized biopsy (NLB). However, an area of concern is the potential for sampling error, with sparse surgical data available concerning follow-up and failure rates. We therefore reviewed our results in patients undergoing SCB for mammographically detected breast abnormalities. Between January 1994 and February 1995, 128 patients underwent SCB. Average age was 56.4 years. Nine patients (7.0%) had histologic evidence of malignancy, with 111 (86.7%) benign diagnoses requiring no further initial intervention. Eight patients (6.3%) proceeded directly to NLB, five because of technical failure of SCB and three because of suspicious initial histology. One of the latter patients had ductal carcinoma in situ. The remaining 111 SCB patients were evaluated at 6 months and 1 year by mammographic and physical examination. Ten patients were lost to follow-up. Of the remaining 101 patients, 98 (97%) had stable mammograms and normal physical examinations. Three patients (3.9%) required subsequent NLB due to progression of the mammographic lesion. Two cases were histologically benign, and 1 patient had ductal carcinoma in situ adjacent to the previous SCB biopsy site. An additional patient underwent NLB for a new radiographic abnormality at a separate location in the ipsilateral breast, which was invasive ductal carcinoma. SCB appears to be an effective alternative to NLB for the majority of patients deemed eligible. Careful mammographic follow-up is warranted for these patients given the small, but real, possibility of sampling error.

Differentiation of benign from malignant pancreatic masses by endoscopic ultrasound

BACKGROUND

It is often difficult to determine whether a mass in the pancreas is benign or malignant. The goal was to evaluate whether endoscopic ultrasound (EUS) can reliably establish whether a mass is benign or malignant.

METHODS

One hundred five patients with possible pancreatic tumors were referred for EUS. Those who were found to have a lesion suspicious for carcinoma and did not have a known malignancy also underwent EUS-guided FNA.

RESULTS

A mass suspicious for cancer was identified in 73 patients, whereas inflammatory changes or a normal pancreas was noted in 32 patients. Four of the latter 32 patients were subsequently found to have cancer. EUS-guided FNA was performed on 47 of the 73 patients with a suspicious mass and was read as cancer in 27 patients, atypia in 10 patients, and benign in 10 patients. All 10 patients with atypia were subsequently confirmed to have cancer, and 6 of the 10 patients with a benign FNA were proved to have a tumor at surgery. EUS could differentiate the lesion as malignant with a sensitivity of 95%, specificity 88%, positive predictive value 95%, and negative predictive value 88%.

CONCLUSIONS

Radial array EUS is helpful in supporting or refuting a diagnosis of cancer in a patient with a pancreatic mass. Although EUS-guided FNA can confirm the diagnosis, a negative FNA should not preclude exploration when clinically indicated.

Transient neuronal depolarization induces tolerance to subsequent forebrain ischemia in rats

BACKGROUND

Minor cortical injury has previously been shown to improve survival in animals subjected to ischemic insults. Although the mechanism by which an ischemia-tolerant state is achieved is not clear, transient neuronal depolarization is thought to play a central role in the development of the tolerance. One way of producing transient neuronal depolarization is by the induction of cortical spreading depression (CSD). The present study was conducted to evaluate the effect of preischemic transient depolarization, induced by CSD, on postischemic neuronal outcome in rats.

METHODS

Unilateral CSD was induced by application of KCl to the frontal cortex (CSD hemisphere) in three groups of isoflurane-anesthetized rats (CSD groups; n = 8/group). Sham animals (n = 12) did not undergo CSD. In a fifth group (n = 8), ketamine was administered during KCl application to inhibit CSD. One, three, or seven days after CSD, animals were subjected to forebrain ischemia produced by bilateral carotid artery occlusion. Injury to the striatum, hippocampus, and cortex was evaluated in hematoxylin and eosin-stained brain sections 3 days after ischemia.

RESULTS

Preischemic CSD reduced postischemic injury in the ipsilateral cortex. The ratio of the number of injured neurons in the CSD hemisphere to that in the non-CSD hemisphere was significantly less in the groups subjected to CSD 1 day (0.51 +/- 0.33), 3 days (0.56 /- 0.22), and 7 days (0.40 +/- 0.17) before ischemia than in the sham operated group (1.11 +/- 0.47). In the ketamine group (CSD inhibition), there were no differences in the extent of injury in the two hemispheres (ratio = 0.84 +/- 0.47). Injury to the striatum and hippocampus was similar among the groups. Within each group, injury to these subcortical structures in the CSD hemisphere was not different from that in the non-CSD hemisphere.

CONCLUSIONS

The data suggest that preischemic depolarization induced by CSD results in an adaptive response that reduces the vulnerability of cortical neurons to subsequent ischemic injury (ischemic tolerance).

Identification of a T-cell receptor from a therapeutic murine T-cell clone

Tumor-infiltrating lymphocytes (TIL) have been successfully used for the treatment of metastatic malignancies in clinical trials and in experimental animal models. Tumor-specific reactivity by TIL is mediated via receptors expressed on the surface of T cells (TcRs), which recognize tumor-associated antigens (TAA) presented in the context of MHC molecules on the surface of tumor cells. The current study was performed to identify the TcR alpha and beta chains from a tumor-specific therapeutic TIL clone that can be used to develop a preclinical animal model for genetically modifying lymphocytes and hematopoietic progenitors with TcR genes. TIL 205 was generated from a subcutaneous implant of MCA-205 fibrosarcoma and at 21 days was cloned by limiting dilution. TIL clone 8, obtained from a culture seeded at one cell/well, mediated specific lysis and specific secretion of gamma-interferon to MCA-205 and WP6, a subclone of MCA 205. No reactivity was observed against other syngeneic sarcoma lines. Anchor polymerase chain reaction analysis determined that antigen recognition by clone 8 was mediated by a TcR consisting of V alpha 3/J alpha 27 and V beta 8.2/D beta 2.1/D beta 2.4. Immunofluorescent staining with V beta subfamily specific monoclonal antibodies revealed that > 95% of the T cells in TIL clone 8 expressed V beta 8.2, confirming that TIL clone 8 was indeed a clone. In contrast, approximately 30% of the T cells in the parental TIL 205 expressed V beta 8.2. The transfer of as few as 500,000 TIL clone 8 cells in conjunction with the systemic administration of recombinant human interleukin-2 mediated regression of established 3-day WP6 lung metastases. Thus, clone 8 recognizes a biologically relevant tumor rejection antigen, making the V alpha 3/J alpha 27-V beta 8.2/D beta 2.1/J beta 2.4 TcR isolated from this clone useful as a probe for cloning the tumor-rejection antigen in the WP6 tumor as well as modeling, in mice, the TcR-based gene therapies being developed for humans.

Characterization of a sustained-release delivery system for combined cytokine/peptide vaccination using a poly-N-acetyl glucosamine-based polymer matrix

Identification of tumor-associated antigens (TAAs) and their class I MHC-restricted epitopes now allows for the rational design of peptide-based cancer vaccines. A biocompatible system capable of sustained release of biologically relevant levels of cytokine and TAA peptide could provide a more effective microenvironment for antigen presentation. Our goal was to test a sustained-release cytokine/TAA peptide-based formulation using a highly purified polysaccharide [poly-N-acetyl glucosamine (p-GlcNAc)] polymer. Granulocyte-macrophage colony-stimulating factor (GM-CSF; 100 microgram) and MART-1(27-35) peptide (128 microgram in DMSO) were formulated into p-GlcNAc. Peptide release was assayed in vitro using interleukin 2 production from previously characterized MART-1(27-35)-specific Jurkat T cells (JRT22). GM-CSF release was assayed via ELISA and proliferation of M-07e (GM-CSF-dependent) cells. Local bioavailability of MART-1(27-35) peptide for uptake and presentation by antigen-presenting cells was demonstrated for up to 6 days (>0.5 microgram/ml). More than 1.0 microgram/ml GM-CSF was concomitantly released over the same period. Biocompatibility and local tissue response to p-GlcNAc releasing murine GM-CSF was determined in C57BL/6 mice via s.c. injection using murine GM-CSF (0. 2 microgram/ml) in 200 microliter of a 2.5% polymer gel. Significant lymphocytic and eosinophilic infiltration was observed 2-7 days after injection with polymer containing murine GM-CSF. The results of our studies show that this biocompatible system is capable of a sustained concomitant release of biologically active peptide and cytokine into the local microenvironment. These findings support further studies to validate a p-GlcNAc delivery system vehicle for a cytokine/TAA peptide-based cancer vaccine.

Alpha-alpha diaspirin crosslinked hemoglobin, nitric oxide, and cerebral ischemic injury in rats

Prior studies indicate that alpha-alpha diaspirin crosslinked hemoglobin (DCLHb) decreases cerebral ischemia. One mechanism whereby DCLHb may ameliorate cerebral ischemia is by binding nitric oxide (NO), which has been implicated as neurotoxic. We assessed the effect of L-NAME (NO synthase inhibitor) and L-arginine (NO substrate) on ischemic brain injury after DCLHb infusion. Rats were randomized to one of the following groups: Control-no hematocrit manipulation; DCLHb-hematocrit decreased to 16% with 10% DCLHb; DCLHb/L-NAME-hematocrit decreased to 16% with DCLHb, and L-NAME given; DCLHb/L-arg-hematocrit decreased to 16% with DCLHb, and L-arginine given. After 90-min of middle cerebral artery occlusion and 4-hr of reperfusion, infarct volume was determined with TTC stain. Infarct volume (mm3, mean +/- SD) was greater in the Control group (142 +/- 16) than the DCLHb (43 +/- 12), DCLHb/L-NAME (45 +/- 14), and DCLHb/L-arg (71 +/- 18) groups (p < 0.05); was greater in the DCLHb/L-arg group than the DCLHb and DCLHb/L-NAME groups (p < 0.05); but was not different between the DCLHb and DCLHb/L-NAME groups. These data indicate that DCLHb decreases ischemic brain injury, and that binding NO may be one mechanism by which DCLHb decreases ischemic brain injury.

Effect of subarachnoid administration of alpha-alpha diaspirin crosslinked hemoglobin on cerebral blood flow in rats

As extravasated red blood cells have been implicated in the pathogenesis of perfusion deficits after subarachnoid hemorrhage, alpha-alpha diaspirin crosslinked hemoglobin (DCLHb) might have a detrimental effect on cerebral perfusion after subarachnoid hemorrhage. We evaluated the effect of subarachnoid administration of DCLHb on cerebral blood flow (CBF). Rats were randomized to receive one of the following solutions into the cisterna magna: Control-0.3 ml of mock cerebrospinal fluid; Blood-0.3 ml of autologous blood; DCLHb-0.3 ml of 10% DCLHb. After 20-min, the area of cerebral hypoperfusion was determined (CBF < 40 ml.100g-1.min-1). The area of hypoperfusion (% area of a coronal brain section, mean +/- SD) was greater in the Blood group (58 +/- 16) than the DCLHb (16 +/- 7) and Control (5 +/- 5) groups (p < 0.05), and was greater in the DCLHb group than the Control group (p < 0.05). These data support a hypothesis that extravasation of blood from the intravascular to the subarachnoid space induces cerebral hypoperfusion. Moreover, the data support the hypothesis that although extravasated molecular hemoglobin decreases CBF, the adverse effect is not as severe as a similar volume of blood.

Hypervolemic-hemodilution during cerebral ischemia in rats: effect of diaspirin cross-linked hemoglobin (DCLHb) on neurologic outcome and infarct volume

In a rat model of middle cerebral artery occlusion (MCAo) and reperfusion (120 min), previous studies have demonstrated that hemodilution with molecular hemoglobin decreases ischemic brain injury. However, long-term recovery data on the therapeutic efficacy of molecular hemoglobin for cerebral ischemia are lacking. Accordingly, we assessed the effect of hemodilution, with alpha-alpha diaspirin cross-linked hemoglobin (DCLHb, 10 g/dl) on neurologic outcome and infarct volume after 120 min of MCAo and 72 h of reperfusion. Ischemia was achieved by passing a 0.26-mm suture, via the external carotid artery, to internally occlude the middle cerebral artery. Immediately after MCAo, the rats were randomized to one of the following groups: Control-hematocrit not manipulated (44%); 30/Hct-hematocrit maintained at 30% with DCLHb; or 16/Hct-hematocrit maintained at 16% with DCLHb. After 120 min of MCAo, the suture was removed and the rats allowed to recover. Daily neurologic examinations were performed, and after 72 h, the brains were analyzed for infarct volume with TTC stain. Infarct volume (mm3) was less in the 30/Hct group (67 +/- 10; mean +/- SD) than in the Control group (141 +/- 17); and less in the 16/Hct group (40 +/- 12) than the other two groups (p < 0.05). Neurologic outcome was improved in both hemodilution groups versus the Control group (p < 0.05). These data are consistent with previous studies, performed in a model of short-term reperfusion, which indicate a dose-dependent decrease in ischemic injury by DCLHb.

The development of cockle, a sheep pelt defect, in relation to size of infestation and time of exposure to Bovicola ovis, the sheep-biting louse

Groups of ten louse-naive lambs were infested with one, ten or 100 female Bovicola ovis and killed 84 days later when an examination of their pelts was made to detect cockle. In a second experiment groups of ten lambs were infested with ten or 100 female B. ovis and groups of lambs were killed every fortnight up to 84 days post-infestation. The pelts were examined in order to detect the earliest time at which cockle could be detected following a louse infestation. Cockle is a nodular condition of the skin arising in response to infestation with B. ovis and is possibly a hypersensitivity on the part of some sheep to antigens of louse origin. In the first experiment cockle did not develop in lambs that had remained louse free or which had been initially infested with one louse. However, five of ten lambs that had been infested with ten lice and all lambs that had been infested with 100 lice developed cockle. In general cockle severity was positively related to the size of the terminal louse population. Group mean louse counts only slightly exceeded the initial infestation in the lambs infested with either ten or 100 lice, and were less than the initial infestation in lambs given only one louse. In the second experiment cockle was first seen 54 days post-infestation, but only in sheep infested initially with 100 lice.

Melanoma-associated tumor antigens and their clinical relevance to immunotherapy

The last few years have witnessed the publication of a large body of evidence demonstrating conclusively the existence of tumor-associated antigens. A large majority of these studies focused on melanoma-associated tumor antigens because of the collective evidence that the immune system can influence the pathogenesis of melanoma, and because of the well-documented, although limited, success of immunotherapeutic modalities in melanoma patients. This review summarizes what is known about melanoma-associated antigenic peptides: their identity, presentation by human leukocyte antigen class I molecules to cognate T cell receptors, and their potential to induce an effective immune response. The inability of melanoma patients to mount an efficacious antitumor response and the distinction between antigenicity (i.e., the ability to express a tumor antigen) and immunogenicity (i.e., the ability to elicit an effective immune response) are discussed. Recruitment of antigen-presenting cells at the tumor site is suggested as a way to overcome tumor-induced immunotolerance. The importance of developing or perfecting laboratory and/or clinical correlates of response to immunotherapeutic modalities is emphasized because of the pressing need for reliable tests that are predictive of clinical outcome.

Surgical management of patients with intermediate thickness melanoma: current role of elective lymph node dissection

The appropriate role of elective hymph node dissection (ELND) in patients with clinical stage I intermediate thickness melanoma lesions remains a dilemma. Despite an impressive number of carefully performed nonrandomized/retrospective studies and two criticized multi-institutional prospective randomized trials, a clear benefit from ELND is still debatable. As a result, there currently is no standard approach for selecting patients who should undergo this procedure. Further prospective trials performed by the Intergroup/National Cancer Institute and World Health Organization (WHO) Melanoma groups, addressing Intermediate thickness extremity and truncal lesions respectively, have recently been completed. No long-term survival data is yet available from either group. Potentially conflicting preliminary results recently presented noted a significant ELND survival advantage for a subgroup of men with axial lesions in the Intergroup study, and no differential in survival demonstrable for the World Health Organization study at a median follow-up of 4 years. One area of agreement among surgeons on either side of the controversy is the need to be able to identify in a minimally invasive manner stage I-II melanoma patients with clinically occult lymph node metastases from the population at risk. Technologies such as polymerase chain reaction and lymphoscintigraphy to improve our ability to detect clinically occult lymph node metastases and facilitate the identification of sentinel node(s) for selective lymphadenectomy hold some promise. Although more research needs to be performed, these approaches potentially would allow for a more directed application of ELND in a much smaller number of melanoma patients. This could provide an entirely novel and more effective approach to the manner in which we evaluate patients with intermediate thickness melanoma lesions and would decrease the significance of this controversy. It is hoped that the long-term data about the appropriate role of ELND from the current prospective trials will provide definitive information on which to base decisions, or that current research will fundamentally alter our approach to these patients. In the interim, surgeons must continue to make their best judgments about the management of regional lymph nodes in an individual patient setting based on prior experience or personal bias.

Kinetic studies on two isoforms of acetyl-CoA carboxylase from maize leaves

The steady-state kinetics of two multifunctional isoforms of acetyl-CoA carboxylase (ACCase) from maize leaves (a major isoform, ACCase1 and a minor isoform, ACCase2) have been investigated with respect to reaction mechanism, inhibition by two graminicides of the aryloxyphenoxypropionate class (quizalofop and fluazifop) and some cellular metabolites. Substrate interaction and product inhibition patterns indicated that ADP and P(i) products from the first partial reaction were not released before acetyl-CoA bound to the enzymes. Product inhibition patterns did not match exactly those predicted for an ordered Ter Ter or a random Ter Ter mechanism, but were close to those postulated for an ordered mechanism. ACCase2 was about 1/2000 as sensitive as ACCase1 to quizalofop but only about 1/150 as sensitive to fluazifop. Fitting inhibition data to the Hill equation indicated that binding of quizalofop or fluazifop to ACCase1 was non-cooperative, as shown by the Hill constant (n(app)) values of 0.86 and 1.16 for quizalofop and fluazifop respectively. Apparent inhibition constant values (K' from the Hill equation) for ACCase1 were 0.054 microM for quizalofop and 21.8 microM for fluazifop. On the other hand, binding of quizalofop or fluazifop to ACCase2 exhibited positive co-operativity, as shown by the (napp) values of 1.85 and 1.59 for quizalofop and fluazifop respectively. K' values for ACCase2 were 1.7 mM for quizalofop and 140 mM for fluazifop. Kinetic parameters for the co-operative binding of quizalofop to maize ACCase2 were close to those of another multifunctional ACCase of limited sensitivity to graminicide, ACC220 from pea. Inhibition of ACCase1 by quizalofop was mixed-type with respect to acetyl-CoA or ATP, but the concentration of acetyl-CoA had the greater effect on the level of inhibition. Neither ACCase1 nor ACCase2 was appreciably sensitive to CoA esters of palmitic acid (16:0) or oleic acid (18:1). Approximate IC50 values were 10 microM (ACCase2) and 50 microM (ACCase1) for both CoA esters. Citrate concentrations up to 1 mM had no effect on ACCase1 activity. Above this concentration, citrate was inhibitory. ACCase2 activity was slightly stimulated by citrate over a broad concentration range (0.25-10 mM). The significance of possible effects of acyl-CoAs or citrate in vivo is discussed.

The comparative ability of some lousicides to reduce cockle in sheep pelts

Sheep naturally infested with the biting louse, Bovicola ovis were treated with a range of organophosphorus and synthetic pyrethroid dip formulations. The sheep were killed 42 days after treatment and the pelts examined for evidence of cockle, a nodular condition that appears in some sheep as a response to the presence of lice. Sheep treated to saturation with dip formulations produced more high quality pelts than did sheep treated with low volume, pour-on or spray-on dips. These differences are suspected to arise because louse populations decline more slowly after treatment with pour-ons or spray-ons than with saturation dips. The removal of lice and regression of cockle resulted in a high percentage of first grade pickled pelts. However, processing through to the dyed crust leather stage highlighted lesions in the same pelts that were not apparent at the pickle stage and lead to a substantial increase in the number of downgraded pelts.

Effect of oncotic pressure of diaspirin cross-linked hemoglobin (DCLHb) on brain injury after temporary focal cerebral ischemia in rats

Previous studies have shown that diaspirin cross-linked hemoglobin (DCLHb, 10 g/dL) decreases cerebral ischemia and the resultant injury in a dose-dependent manner, requiring large volumes of DCLHb for maximum efficacy. We assessed the effect of a more concentrated (20 g/dL) and more hyperoncotic preparation of DCLHb on cerebral infarction volume. Immediately after middle cerebral artery occlusion, rats were randomized to one of the following groups: Control, hematocrit not manipulated; 10/Hb, hematocrit decreased to 30% with 10% DCLHb (oncotic pressure 43 mm Hg); 7.5/Alb, hematocrit decreased to 30% with 7.5% albumin (oncotic pressure 43 mm Hg); 20/Hb, the same dose of DCLHb (20%, oncotic pressure 129 mm Hg) as the 10/HB group (half the volume); or 15/Alb, the same dose of albumin (15%, oncotic pressure 130 mm Hg) as the 7.5/Alb group half the volume). After 90 min of ischemia, 72 h of reperfusion was allowed. Infarction volume (mm3, mean +/- sd) was less in the DCLHb groups (10/Hb = 79 +/- 17; 20/HB = 51 +/- 14) than the oncotically matched albumin groups (7.5/Alb = 124 +/- 21; 15/Alb = 85 +/- 18) and the Control group (135 +/- 17) (P < 0.05). These data indicate that in this model of cerebral ischemia, DCLHb decreases ischemic brain injury more effectively than albumin, and that a hyperoncotic preparation of DCLHb is preferable.