Definition of TCR recognition sites on Ld-tum- complexes

The P911 variant of the P815 mastocytoma was shown by Lurquin et al. (Cell 58:293, 1989) to elicit rapid tumor rejection in a syngeneic host. This rejection was mediated by Ld-restricted cytotoxic T lymphocytes (CTL) for which targets could be sensitized by the synthetic peptide designated tum- (P91A-.12-24). In a previous study, T cell clones specific for Ld-tum- complexes displayed very restricted TCR usage and a characteristic TCR motif in the V alpha CDR3 region, predicted to interact with peptide. However, in contrast to the majority of Ld peptide ligands that are nonamers, the tum- peptide is a 13-mer and its sequence does not fit the Ld binding motif. Thus, to define shorter versions of the tum- 13-mer and residues involved in TCR recognition, nonamer derivatives were synthesized and compared in several different binding and functional assays. From these comparisons, the peptide TQNHRALDL was found to be the optimal nonamer. CTL recognition of Ala-substituted analogues of this peptide indicated that the His and Arg residues at positions 4 and 5 are important for TCR contact. We propose that these basic residues of the tum- peptide interact with the previously defined acidic residues in the CDR3 region of several TCR known to recognize Ld-tum- complexes.

Self-peptides bound to the type I diabetes associated class II MHC molecules HLA-DQ1 and HLA-DQ8

Genetic susceptibility to several autoimmune disorders is associated with the expression of certain MHC class II alleles. Insight into the etiology of such diseases awaits the identification of the class II restriction elements and the possible pathogenic peptides. Towards these aims, self-peptides bound to HLA-DQ1 and HLA-DQ8, allotypes considered to be neutral and permissive respectively towards the development of insulin-dependent diabetes mellitus, are reported. These naturally processed peptides were isolated from immunoaffinity purified HLA-DQ molecules expressed in cultured B lymphocytes. The chromatographic profiles of the peptide repertoires are unique, whereas the size distributions exhibit general similarity to those reported for naturally processed self-peptides bound to HLA-DR. Twenty-eight individual peptides representing 10 nested sets were identified by combined Edman microsequencing and mass spectrometry. Peptide length varied from 13 to 74 amino acids. Source proteins included MHC molecules and other integral membrane proteins, as well as secretory, cytosolic and mitochondrial proteins. Promiscuous invariant chain peptides were identified among the self-peptides bound to HLA-DQ8. No dominant amino acid markers suggestive of particular enzymatic processing events were detected. Some structural features of DQ1 and DQ8 that may relate to the bound peptides are discussed. Peptide specificity was confirmed in binding assays with purified HLA-DQ and HLA-DR protein.

In vitro modeling of spinal anesthesia. A digital video image processing technique and its application to catheter characterization

BACKGROUND

Maldistribution of intrathecal local anesthetic has recently been implicated as a contributor to neurotoxic injury. In vitro modeling can be used to understand the distribution of anesthetic agents within the subarachnoid space. We describe an in vitro modeling technique that uses digital video image processing and its application to catheter injection of local anesthetic.

METHODS

A clear plastic model of the subarachnoid space, including a simulated spinal cord and cauda equina, was filled with lactated Ringer's solution. Phthalocyanine blue dye of known concentration was injected into the model through small-bore (28-G) and large-bore (18-G) catheters. Injections were performed at a variety of controlled rates and sacral catheter positions, and the propagation of dye throughout the model was recorded on videotape, digitized by computer, and converted to a two-dimensional image of dye concentration. A subset of data was compared with results obtained from spectrophotometric analysis.

RESULTS

There was a strong correlation (r = 0.98) between data obtained with analysis by digital video image processing and those obtained spectrophotometrically. Catheter size, catheter angle, and injection rate significantly influenced the distribution and peak concentration of simulated anesthetic. No major differences in distribution or peak concentration were observed with the two types of 28-G catheters.

CONCLUSIONS

The digital video image processing technique can be used to quantify anesthetic distribution rapidly within a model of the subarachnoid space without disturbing the distribution. The current results demonstrate a strong dependence of anesthetic distribution on catheter angle, catheter size, and injection rate. Comparisons between 28-G catheters suggest that the difference in reported incidence of cauda equina syndrome associated with different 28-G catheters cannot be explained on the basis of differences in anesthetic distribution.

Hematopoietic elements associated with adrenal glands. A study of the spectrum of change in nine cases

We report nine cases of hematopoietic elements or myelolipomatous foci that were found in association with normal and neoplastic adrenal glands. A spectrum of change occurred that ranged from small clusters of purely erythroid or myeloid cells to microscopic myelolipomas that contained a mixture of hematopoietic elements. Recognition of the myeloid elements was facilitated with the use of the chloroacetate esterase (Leder) stain and a CD15 (myelomonocytic antigen) immunohistochemical stain. The majority (six of nine) of these cases were found in association with cortical adenomas in middle-aged women, but myelolipomatous foci were also found in association with an adrenocortical carcinoma, a pheochromocytoma, and a renal angiomyolipoma. The histogenesis of the foci remained speculative. However, the association with hormonally active neoplasms suggested that the hormonal microenvironment may have played a role in the development of the myelolipomatous foci.

Oncogene amplification screening by labeled primer multiplex polymerase chain reaction

This paper describes an improved procedure for rapid detection of amplified genes in fresh or formalin-fixed, paraffin-embedded tissues. Utilizing a multiplex differential polymerase chain reaction with radioactively labeled primers and electrophoresis of the products through thin gels, it is possible to screen for oncogene amplification more rapidly and reproducibly than has been previously demonstrated. This procedure takes advantage of thin vertical gels with external cooling, which allows sharp band resolution. Four separate gels can be electrophoresed at the same time in a single gel box. Because each gel slab contains 10 or more lanes, 40 or more samples can be assayed for gene amplification simultaneously. The entire procedure can be carried out from formalin-fixed, paraffin-embedded tissue to finish in 8 h when combined with a sonication technique for DNA extraction.

Familial occurrence of subependymoma. Report of two cases

Subependymomas are unusual tumors believed to arise from the bipotential subependymal cell. Previous reports of familial occurrence of subependymoma have involved monozygous twins and siblings. The authors describe the first reported occurrence of fourth ventricular subependymoma in a father and son, suggesting the possibility of direct inheritance.

DNA ploidy and P-glycoprotein expression as predictive factors of response to neoadjuvant chemotherapy for invasive bladder cancer

OBJECTIVE

To identify a factor or factors that could predict response of muscle invasive transitional cell carcinoma of the bladder to neoadjuvant cisplatin, methotrexate, and vinblastine chemotherapy.

METHODS

DNA ploidy analysis and immunohistochemical staining for p-glycoprotein (the product of the multidrug resistance gene, MDR-1) were performed on bladder biopsies obtained prior to chemotherapy. Radical cystectomy specimens were utilized for complete pathologic staging.

RESULTS

Tissue was available for DNA ploidy analysis in 25 patients. Ten patients had complete responses to neoadjuvant chemotherapy and 15 patients did not respond. Nineteen patients had aneuploid tumors, of which 7 (37%) were complete responders. Six patients had diploid tumors, of which 3 (50%) were complete responders. This difference was not statistically significant. Tissue was available for immunostaining in 15 patients. Seven of 9 patients (78%) who did not respond to chemotherapy stained positively for p-glycoprotein, whereas 5 of 6 patients (83%) who had complete responses stained positively. This difference was not statistically significant.

CONCLUSIONS

Neither DNA ploidy nor p-glycoprotein expression appears to predict successfully those patients likely to respond to neoadjuvant cisplatin, methotrexate, and vinblastine chemotherapy in the treatment of invasive bladder cancer.

Crypt cell thymidine incorporation in ileal urinary pouch. Preliminary report

This is a brief communication about mucosal change in ileal urinary reservoirs, the earliest reported observations to date. Previous authors described early villous atrophy and crypt elongation, late panmucosal atrophy and metaplasia. Crypt cell proliferation should be a forerunner of these events and therefore warrants quantitative measurement. We studied continent pouches in dogs on postoperative days 42 and 43 using in vivo tritiated thymidine incorporation into crypt cell DNA, a novel application of autoradiography for urinary reservoirs. Adjacent normal ileum provided the internal control. Increased crypt cell thymidine incorporation was confirmed at this early time.

Use of thiazole orange homodimer as an alternative to ethidium bromide for DNA detection in agarose gels

Detection of polymerase chain reaction-amplified DNA fragments is commonly accomplished by visualizing the products in electrophoretic agarose beds with the use of ethidium bromide under ultraviolet light. However, ethidium bromide is mutagenic, and special handling and disposal precautions must be used. We report the use of a nonmutagenic dye, thiazole orange dimer (TOTO), which can be substituted for ethidium bromide. The excitation maximum for TOTO under ultraviolet light is 488 nm, and the absorption maximum is 510 nm, necessitating photographic filters different from those used for ethidium bromide for optimal results. Of particular importance in TOTO's use is the quantity used for each gel lane, since excess TOTO will cause unacceptable product mobility retardation. TOTO is only slightly more expensive than ethidium bromide. Overall, this stain provides very good visualization of polymerase chain reaction--amplified DNA bands in agarose gels. We believe the use of this safer reagent will become more widespread with increased regulation of laboratory activities.

Fine-needle detection of cytomegalovirus parotitis in a patient with acquired immunodeficiency syndrome

Parotid enlargement is common in patients infected with human immunodeficiency virus type 1. We present a case of cytomegalovirus infection of the parotid gland in a patient with the acquired immunodeficiency syndrome. This case is notable because fine-needle aspiration provided the diagnosis. We therefore present a quick and inexpensive method of detecting a potentially fatal infection that has previously been unrecognized by the medical community.

C-erbB-2 expression and codon 12 K-ras mutations both predict shortened survival for patients with pulmonary adenocarcinomas

We evaluated the prognostic significance of p185c-erbB-2 expression and ras gene mutations in all patients diagnosed with a pulmonary adenocarcinoma between 1982 and 1985 at the University of Iowa. p185c-erbB-2 expression was detected in 15 cases (34%). A ras gene mutation was found in 16 cases (36%) and all were in codon-12 of K-ras. No N-ras mutations were identified. Both p185c-erbB-2 expression and a K-ras mutation were found only in codon-12 and present in six cases (14%). By univariate analysis p185c-erbB-2 expression was associated with shortened survival (P = 0.02) while the presence of a K-ras mutation was not (P = 0.16). Multivariate analysis by the Cox proportional hazards model, controlling for patient age and tumor stage, also continued to identify p185c-erbB-2 expression as an independent unfavorable prognostic factor (P = 0.01). In this model a K-ras mutation also approached significance as a poor prognostic indicator (P = 0.06). The impact of both p185c-erbB-2 expression and a K-ras mutation on survival was additive and highly significant (P = 0.004). This additive nature suggests that together these two markers identify a high-risk population of lung adenocarcinoma patients that may benefit from aggressive therapy.

Topical effect of intravesical oxybutynin

Intravesical oxybutynin was instilled into rat bladders in graded doses by repeated catheterization to study the local bladder effects of drug concentration and incidental urinary infection. On the thirteenth day, after 5 doses, bladders were recovered for measurement and histological study. In the highest dose group, systemic absorption from the bladder caused weight loss and cachexia. However, in no group was there any clear evidence of drug-related mucosal or bladder wall change. Instead, the two high dose groups seemed somehow protected from the combined adverse effects of catheterization and infection.

Association between clinical lameness and Borrelia burgdorferi antibody in dairy cows

Results of an ELISA, indirect fluorescent antibody (IFA) test, and immunoblot analysis (western blotting) for antibody to Borrelia burgdorferi in a sample of 216 lactating dairy cows were compared. The microscopic microtitration agglutination test for antibody to 6 serovars of Leptospira interrogans was also performed to evaluate possible cross-reactivity between B burgdorferi and L interrogans. Using western blotting as the standard test against which the ELISA and IFA test were compared, the ELISA had greater sensitivity (50% in summer and 38% in spring) with similar specificity (83 and 82%), compared with the IFA test (sensitivity, 6 and 5%; specificity, 90 and 83%). In addition, seropositivity to B burgdorferi, using the ELISA, was not found to be associated with seropositivity to L interrogans serovars. A matched case-control study evaluating the association between clinical lameness and antibody to B burgdorferi was performed in lactating dairy cows of 17 Minnesota and Wisconsin herds. Sera from case and control cows matched by herd, parity, and stage of lactation were evaluated, using an ELISA for B burgdorferi antibody during 2 seasons. High B burgdorferi antibody values were associated with clinical lameness in dairy cows (P = 0.006 in summer and P = 0.04 in spring).

Prevalence and severity of lameness in lactating dairy cows in a sample of Minnesota and Wisconsin herds

An epidemiologic study investigating the prevalence of lameness in lactating dairy cows was performed in 17 dairy herds in Minnesota and Wisconsin. The mean herd size was 50 cows. Cows from 14 herds were housed in stanchions or tie stalls, and cows from 3 herds in free stalls or dry lot. During visits to each farm in the summer and subsequent spring, 2 investigators simultaneously but independently evaluated the ambulation of lactating cows by use of a standardized scoring system. The lameness scoring system was reliable at the 2 visits, with 92.7 and 91.3% agreement between the 2 observers and kappa coefficients of 0.60. The prevalence of lameness detected by the investigators ("clinical" lameness) was 13.7% (117/853) in summer and 16.7% (134/801) in spring in lactating dairy cows. These prevalences were 2.5 times higher than those estimated by the herd managers. Parity was significantly (P < or = 0.03) associated with lameness, with higher prevalence of clinical lameness found in cows of higher parity.

Procoagulant activities expressed by peripheral blood mononuclear cells

These combined data support the concept that the procoagulant response elicited by mononuclear cells, particularly monocytes, is accomplished through regulated binding site-mediated (or perhaps "receptor"-mediated) assembly of proteolytic activities at their membrane surface. Because the work of several laboratories indicate that the monocytes provide the appropriate membrane surface for the assembly and function of all the coagulation complexes required for thrombin production in vivo, monocytes may provide a unique opportunity to investigate how coagulant reactions are regulated on cell surfaces through both receptor-mediated events as well as by channeling a product of one reaction to serve as a mediator of a second reaction.

H-ras-1 gene mutations in basal cell carcinoma: automated direct sequencing of clinical specimens

Ras oncogenes are activated by point mutations occurring in codons 12, 13 or 61 and almost any base pair mutation occurring within the first two positions of any of these codons results in activation of the gene. Although ras point mutations have been reported to occur in several skin neoplasms including squamous carcinoma, keratoacanthoma and melanoma, their frequency of occurrence in basal cell carcinoma is not known. We examined basal cell carcinomas from 13 patients for activating mutations in the H-ras-1 gene by automated direct sequencing of polymerase chain reaction assay amplified targets. We amplified sequences in exon 1 that flanked codons 12 and 13 and amplified sequences in exon 2 that flanked codon 61. The PCR products were centrifuged and directly sequenced using antisense primers in an automated sequencer using fluorescent dideoxyterminators. One tumor was found to show an activating G to A transversion in codon 13 which code for aspartic acid instead of glycine. Although H-ras mutations may be found in some skin tumors, they are not frequent in basal cell carcinomas. From this study we believe that direct sequencing of clinical material is of value and has advantages over other techniques. Additional studies need to be undertaken to understand the true clinical significance of ras mutations in basal cell carcinomas when they occur.

Cystic acoustic schwannomas: MR characteristics

PURPOSE

To evaluate the spectrum of MR characteristics of cystic acoustic schwannoma and to investigate its incidence.

METHODS

We retrospectively reviewed the MR findings and clinical records of 16 patients with cystic acoustic schwannomas. In addition, the MR examinations of 411 consecutive patients referred for clinical suspicion of acoustic schwannomas were reviewed retrospectively to assess the incidence of acoustic schwannomas with cystic lesions arising from the internal auditory canal.

RESULTS

Of the 16 acoustic schwannomas with MR evidence of intramural cysts, 11 tumors had single small cysts, and five had multiple intramural cysts of variable size. Intramural cysts in 11 of the 16 tumors exhibited higher signal intensity than that of cerebrospinal fluid; the remainder were isointense to cerebrospinal fluid on both T1- and T2-weighted images. All intramural cysts showed circumferential enhancement after contrast administration. Nine of the 16 cystic acoustic schwannomas also had MR evidence of extramural/arachnoid cysts. Six of the extramural/arachnoid cysts had epicenters away from the dural interface, and the other three cysts were broadly based against the dura. The incidence of cystic acoustic schwannomas was 11.3% and association with extramural/arachnoid cysts 7.5%.

CONCLUSION

Our series suggests that cystic changes in acoustic schwannomas and the association with extramural/arachnoid cysts are not as rare as previously reported by other diagnostic methods. The high signal intensity of intramural cysts is probably related to necrotic material, blood, or colloid-rich fluid. The difference in the MR characteristics of extramural/arachnoid cysts associated with acoustic schwannomas and those of typical arachnoid cysts not associated with neoplasia may be related to higher protein and/or colloid contents secreted by the tumor. Most extramural/arachnoid cysts had epicenters between the tumor and brain, suggesting that the most likely mechanism of formation is peritumoral adhesions. It creates a pseudo-duplication caused by the trapping of fluid between the leptomeninges and the mass, resulting in an acquired type of arachnoid cyst.

Factor Xa interacts with two sites on monocytes with different functional activities

Studies were performed to elucidate the functional significance of factor Xa interactions at the monocyte membrane in the presence and absence of factor Va, with respect to prothrombin and factor IX cleavage. Factor Xa-catalyzed prothrombin activation at the monocyte surface was absolutely dependent on the addition of factor Va, indicating that thrombin was generated solely by a membrane-bound complex of factors Va and Xa. In contrast, in the absence of added factor Va, factor Xa bound to monocytes catalyzed the cleavage of factor IX to the nonenzymatic intermediate factor IX alpha through a reaction that was dependent on both monocyte and factor Xa concentration. At limiting factor Xa concentration, added factor Va inhibited the factor Xa-catalyzed cleavage of factor IX, suggesting that a monocyte-bound complex of factors Va and Xa did not recognize factor IX as a substrate. These combined data suggest that factor Xa interacts with the monocyte through two sites which can be distinguished by their requirement for added factor Va and their expression of different functional activities. Both functional sites could be distinguished also by their differential susceptibility to inhibition by a monoclonal antibody directed against the light chain of factor Va (alpha-HFV1). At the monocyte surface, the factor Va/Xa-catalyzed activation of prothrombin was maximally inhibited with 0.25 mumol/L alpha-HFV1, whereas 1.0 mumol/L alpha-HFV1 was required to effect 50% inhibition of the factor Xa-catalyzed cleavage of factor IX. The ability of factor Va to modulate factor Xa substrate specificity was investigated further. Factor Xa bound to thrombin-activated platelets either through platelet-released factor Va or added factor Va did not cleave factor IX. Consistent with this result, a plasma concentration of factor IX had no effect on thrombin generation catalyzed by a platelet-bound complex of factors Va and Xa. In marked contrast, factor Xa bound to phospholipid vesicles either independently or in complex with factor Va catalyzed factor IX cleavage with equal efficiency. These combined data indicate that factor Va bound to cell surfaces modulates factor Xa substrate specificity, whereas no discriminatory effect is conferred by factor Va bound to phospholipid vesicles. Thus, by providing two distinct sites at its membrane surface, the monocyte modulates factor Xa binding and the functional activity expressed by the bound enzyme, depending on the availability of factor Va.