Pancreatic tumours: molecular pathways implicated in ductal cancer are involved in ampullary but not in exocrine nonductal or endocrine tumorigenesis

Alterations of K- ras, p53, p16 and DPC4/Smad4 characterize pancreatic ductal cancer (PDC). Reports of inactivation of these latter two genes in pancreatic endocrine tumours (PET) suggest that common molecular pathways are involved in the tumorigenesis of pancreatic exocrine and endocrine epithelia. We characterized 112 primary pancreatic tumours for alterations in p16 and DPC4 and immunohistochemical expression of DPC4. The cases included 34 PDC, 10 intraductal papillary-mucinous tumours (IPMT), 6 acinar carcinomas (PAC), 5 solid-pseudopapillary tumours (SPT), 16 ampulla of Vater cancers (AVC) and 41 PET. All tumours were also presently or previously analysed for K- ras and p53 mutations and allelic loss at 9p, 17p and 18q. Alterations in K- ras, p53, p16 and DPC4 were found in 82%, 53%, 38% and 9% of PDC, respectively and in 47%, 60%, 25% and 6% of AVC. Alterations in these genes were virtually absent in PET, PAC or SPT, while in IPMT only K- ras mutations were present (30%). Positive immunostaining confirmed the absence of DPC4 alterations in all IPMT, SPT, PAC and PET, while 47% of PDC and 38% of AVC were immunonegative. These data suggest that pancreatic exocrine and endocrine tumourigenesis involves different genetic targets and that among exocrine pancreatic neoplasms, only ductal and ampullary cancers share common molecular events.

Relapse of low-grade gastric MALT lymphoma after Helicobacter pylori eradication: true relapse or persistence? Long-term post-treatment follow-up of a multicenter trial in the north-east of Italy and evaluation of the diagnostic protocol's adequacy

The effect of eradication of Helicobacter pylori on early stage gastric low-grade MALT lymphoma in 76 patients with follow-up of at least 1 year (12-63 months, mean 28) is reported. No regression was found in five cases after 12-48 months. In one case surgical resection detected the involvement of perigastric lymph nodes overlooked by endoscopic ultrasonography (EUS). Neither progression of the disease nor a high-grade component was documented by repeated gastric mappings, EUS and complete stagings in the other four cases. After histological remission five relapses of low-grade and one relapse of high-grade MALT lymphoma were found 12-48 months after eradication. Subsequent histological remission, without any additional therapy, was found in three relapsed cases. A rapid and persistent histological remission was obtained in 56 patients (73%). A late remission was observed in six cases. Monoclonal remission was found in half of the patients and was frequently delayed. Persistent monoclonality was associated with histological remission in the vast majority of patients. Our data confirm H. pylori eradication as the first choice therapy for early stage gastric low-grade MALT lymphoma and recommend extensive bioptic mapping and endoscopic sonography both in the local staging and in the regression evaluation. The rare cases of late remission encourage us to wait for at least 1 year after eradication of H. pylori. Longer follow-up studies will clarify the meaning of histological relapse/persistence and late remission. The study of non-responder cases could show us a step in lymphomagenesis.

Alcohol, smoking and papillomavirus infection as risk factors for esophageal squamous-cell papilloma and esophageal squamous-cell carcinoma in Italy

Esophageal papilloma, an infrequent benign tumor, and esophageal squamous-cell carcinoma sometimes appear to be associated with human papillomavirus (HPV) infection, HPV being implicated in anogenital carcinogenesis. Our aim was to assess whether there is any epidemiological difference in terms of risk factors for papilloma and cancer. From 1989 to 1996, a total of 12,011 patients (53% male, median age 52.7 years) were submitted to esophagogastroduodenoscopy by our Digestive Endoscopy Service. The genome of HPV was sought by PCR using 2 different primer sets. Of the total, 42 subjects (0.35%), 50% male with a mean age of 45.1 years, were suffering from esophageal squamous-cell papilloma and 45 (0.37%), 91% male with a mean age of 63.0 years, from esophageal squamous-cell carcinoma. Of these patients, only 2 with papilloma were HPV(+). Compared with the general endoscopic population, patients with papilloma do not present significantly different characteristics (even in terms of frequency of esophagitis and hiatal hernia). Those with carcinoma differ significantly both from the general endoscopic population and from those with papilloma in that they are more often male (p < 0. 0001), older (p < 0.0001) and drinkers (p < 0.0001); they differ significantly only from the general population, but not from the papilloma patients, in smoking habits. Papilloma appears to be neither a lesion involving a risk of development into a malignancy nor a marker for any such risk. Environmental factors, such as alcohol and smoking, appear to play a decisive role in esophageal carcinogenesis in northern Italy.

Alcohol, smoking and papillomavirus infection as risk factors for esophageal squamous-cell papilloma and esophageal squamous-cell carcinoma in Italy

Esophageal papilloma, an infrequent benign tumor, and esophageal squamous-cell carcinoma sometimes appear to be associated with human papillomavirus (HPV) infection, HPV being implicated in anogenital carcinogenesis. Our aim was to assess whether there is any epidemiological difference in terms of risk factors for papilloma and cancer. From 1989 to 1996, a total of 12,011 patients (53% male, median age 52.7 years) were submitted to esophagogastroduodenoscopy by our Digestive Endoscopy Service. The genome of HPV was sought by PCR using 2 different primer sets. Of the total, 42 subjects (0.35%), 50% male with a mean age of 45.1 years, were suffering from esophageal squamous-cell papilloma and 45 (0.37%), 91% male with a mean age of 63.0 years, from esophageal squamous-cell carcinoma. Of these patients, only 2 with papilloma were HPV(+). Compared with the general endoscopic population, patients with papilloma do not present significantly different characteristics (even in terms of frequency of esophagitis and hiatal hernia). Those with carcinoma differ significantly both from the general endoscopic population and from those with papilloma in that they are more often male (p < 0. 0001), older (p < 0.0001) and drinkers (p < 0.0001); they differ significantly only from the general population, but not from the papilloma patients, in smoking habits. Papilloma appears to be neither a lesion involving a risk of development into a malignancy nor a marker for any such risk. Environmental factors, such as alcohol and smoking, appear to play a decisive role in esophageal carcinogenesis in northern Italy.

Alcohol, smoking and papillomavirus infection as risk factors for esophageal squamous-cell papilloma and esophageal squamous-cell carcinoma in Italy

Esophageal papilloma, an infrequent benign tumor, and esophageal squamous-cell carcinoma sometimes appear to be associated with human papillomavirus (HPV) infection, HPV being implicated in anogenital carcinogenesis. Our aim was to assess whether there is any epidemiological difference in terms of risk factors for papilloma and cancer. From 1989 to 1996, a total of 12,011 patients (53% male, median age 52.7 years) were submitted to esophagogastroduodenoscopy by our Digestive Endoscopy Service. The genome of HPV was sought by PCR using 2 different primer sets. Of the total, 42 subjects (0.35%), 50% male with a mean age of 45.1 years, were suffering from esophageal squamous-cell papilloma and 45 (0.37%), 91% male with a mean age of 63.0 years, from esophageal squamous-cell carcinoma. Of these patients, only 2 with papilloma were HPV(+). Compared with the general endoscopic population, patients with papilloma do not present significantly different characteristics (even in terms of frequency of esophagitis and hiatal hernia). Those with carcinoma differ significantly both from the general endoscopic population and from those with papilloma in that they are more often male (p < 0. 0001), older (p < 0.0001) and drinkers (p < 0.0001); they differ significantly only from the general population, but not from the papilloma patients, in smoking habits. Papilloma appears to be neither a lesion involving a risk of development into a malignancy nor a marker for any such risk. Environmental factors, such as alcohol and smoking, appear to play a decisive role in esophageal carcinogenesis in northern Italy.

Leukocyte adhesion molecules and leukocyte-platelet interactions during hemodialysis: effects of different synthetic membranes

Membranes made from synthetic polymers, in general, are considered as being biocompatible membranes and tend to be treated as a homogeneous group. However, all of these membranes have multiple and different characteristics that may contribute to interactions with blood components. As a consequence, the biocompatibility profile of synthetic membranes may vary. In the present cross-over study, we examined by flow cytometry the effects (expressed as % change from predialysis values) of three different synthetic polymers (polysulfone, PSF; polyacrylonitrile-co-sodium methallyl sulfonate, AN69; ethylenevinylalcohol, EVAL) on the expression of leukocyte adhesion molecules (CD11b/CD18, CD15s) and the interactions between leukocytes and platelets under conditions of routine clinical use. For neutrophils, a statistically significant difference was found in CD15s expression for EVAL as compared to AN69 (p<0.05) and in CD11b/CD18 expression for PSF as compared to both EVAL (p<0.01) and AN69 (p<0.05). No difference between membranes was found on the expression of such adhesive molecules on monocytes. Significant differences in platelet-neutrophil (but not in platelet-monocyte) coaggregate formation were observed between PSF and both EVAL (p<0.001) and AN69 (p<0.01). Reactive oxygen species production by neutrophil population during hemodialysis was significantly different between each pair of synthetic polymers (PSF vs EVAL, p<0.001; PSF vs AN69, p<0.001; AN69 vs EVAL, p<0.05). Our data demonstrate that in terms of leukocyte adhesion receptors and platelet-leukocyte interactions, the biocompatibility profile of the synthetic membranes polysulphone, AN69 and EVAL shows many similarities but also several significant differences. Our results support the concept that biocompatibility evaluation of each membrane should be based exclusively on data generated by that membrane in order to avoid errors based on assumptions about group characteristics.

Expression of antisense chalcone synthase RNA in transgenic hybrid walnut microcuttings. Effect on flavonoid content and rooting ability

Walnut somatic embryos (Juglans nigra x Juglans regia) were transformed with a vector containing a neomycin phosphotransferase II, a beta-glucuronidase and an antisense chalcone synthase (chs) gene. This antisense construct included a 400 bp cDNA fragment of a walnut chs gene under the control of the duplicated CaMV-35S promoter. Molecular, biochemical and biological characterizations were performed both on transformed embryos propagated by secondary somatic embryogenesis and on microshoots developed by in vitro culture of embryonic epicotyls from somatic embryos. Thirteen transformed lines with the vector containing the antisense chs gene, one line with only the gus and nptII genes and one untransformed line were maintained in tissue culture. Six of the antisense lines were shown to be flavonoid-deficient. They exhibited a strongly reduced expression of chs genes, very low chalcone synthase activity and no detectable amounts of quercitrin, myricitrin, flavane-3-ols and proanthocyanidins in stems. Rooting tests showed that decreased flavonoid content in stems of antisense chs transformed lines was associated with enhanced adventitious root formation. Free auxin and conjugated auxin contents were determined during the latter phase of the micropropagation, and no variations were detected between control and antisense chs transformed lines. The in vitro plants developed a large basal callus and apical necrosis upon auxinic induction and the transformed lines highly deficient in flavonoids were more sensitive to exogenous application of indolebutyric acid (IBA).

[Rectal endometriosis. Apropos of a clinical case]

Regarding a case of rectal endometriosis, presenting with cyclic menstrual rectal bleeding, the authors discuss the clinical and treatment aspects of such a rare pathology. History was sufficient to indicate the diagnosis which was confirmed by the histological examination of the excised rectal tract. These observations underline the diagnostic difficulty; the surgical approach is the treatment of choice when medical treatment gives no success.

[Peritoneal echinococcus: report of a case]

The Authors report a case of peritoneal echinococcal cyst and discuss the pathogenetic and clinical aspects as well as the diagnostic and therapeutic approaches of such a particular localization. They underline the need of a radical surgical treatment in order to definitively eliminate the parasite and the disease.

Routine application of polymerase chain reaction in the diagnosis of monoclonality of B-cell lymphoid proliferations

We evaluated four polymerase chain reaction (PCR) methods for their efficiency in detecting monoclonality in a well-characterized panel of frozen and paraffin-embedded B-cell lymphoid proliferations. These approaches (referred to as FR3, FR3A, FR2, and FR1) are based on amplification of rearranged immunoglobulin heavy chain genes, using primers recognizing framework regions I, II, or III. FR3, FR3A and FR2 approaches reproducibly detected monoclonality in 51%, 72%, and 67% of DNAs from frozen lymphomas, respectively. No false-positives were observed. The combination of FR2 and FR3A methods raised the figure to 85%. Comparable results were obtained using paraffin-embedded lymphomas. Reproducibility of FR1 approach was unsatisfactory. The efficiency of all PCR approaches varied depending on lymphoma type. The highest detection rate was in small/intermediate cell and the lowest in centro-follicular lymphomas. Limiting dilution assays showed that PCR methods were able to detect monoclonal B-cell DNA representing 5% of nonlymphoid and 20% of polyclonal B-cell DNA. A diagnostic protocol may include quick and cost-effective PCR screening, particularly in cases of undetermined small cell lymphoid proliferations observed in fine needle aspirates or endoscopic biopsies. This would also reduce call-up of patients to obtain unfixed biopsies.

ras-family gene mutations in neoplasia of the ampulla of Vater

Mutations in the first and second exons of Ha-, Ki- and N-ras oncogenes were investigated in 17 epithelial tumors of the ampulla of Vater by single-strand conformation polymorphism analysis and direct sequencing of DNA fragments amplified by polymerase chain reaction. The panel included 12 intestinal-type adenocarcinomas, 3 villous adenomas, 1 papillary carcinoma and 1 neuroendocrine carcinoma. Six cases (35%) contained ras mutations, affecting codon 12 of Ki-ras in 2 adenomas and 3 carcinomas, and of N-ras in 1 adenoma. All mutations were found in adenomas and among cancers with adenomatous areas, whereas none of the cases lacking adenomatous areas contained mutations. This suggested that ampullary cancers represent heterogeneous diseases with respect to the presence or absence of adenomatous areas and, among those with adenomatous areas, with respect to the presence of activated ras genes. Ki-ras mutated cases included 3 of 4 tumors which mainly involved the intraduodenal bile duct, thus suggesting that a proportion of Ki-ras-mutated ampullary cancers might correspond to those originating from the epithelium of the bile duct component of the ampulla.

Clear cell ("sugar") tumor of the lung is a lesion strictly related to angiomyolipoma--the concept of a family of lesions characterized by the presence of the perivascular epithelioid cells (PEC)

We report a comparative study of 3 clear cell tumors of the lung (CCTL) and 3 angiomyolipomas (AML) of the kidney. Morphological analysis shows that the cells of CCTL are identical to the perivascular epithelioid component of AML. Phenotypically they both consistently expressed melanoma-associated antigens recognized by Moabs HMB45 and HMSA-1, while they were negative for HMSA-5. A minority of cells also expressed S-100 protein, vimentin and actin. In addition, one case of CCTL showed mature adipose tissue entrapped in the proliferation, thus suggesting an intermediate form between CCTL and AML. Based on morphological and phenotypical similarities, it is suggested that CCTL and AML belong to the same family of lesions, characterized by the presence of a peculiar muscle cell, expressing different melanoma-associated antigens.

Pancreatic cancer in Europe: Ki-ras gene mutation pattern shows geographical differences

Seventy-seven pancreatic adenocarcinomas (60 Spanish and 17 Italian) were tested for Ki-ras gene mutations by analysis of polymerase chain reaction amplified sequences. Mutations involving codon 12 (GGT; gly) were detected in 16 Italian and 46 Spanish cases (80.5% in total). All Italian mutations involved the second base and were G to A transitions (GAT; asp) in 8 cases and G to T transversions (GTT; val) in the remaining 8. Forty-two Spanish mutations were characterized. Thirty-eight were at the second and 4 at the first base: asp in 24 cancers, val in 14, arg (CGT) in 2 and cys (TGT) in 2. Previous European studies and our present data show that 149 of the 186 pancreatic cancers harbored a codon 12 Ki-ras mutation (80%), the large majority affecting the second base (73%), with a transitions/transversions ratio of 1.3:1. However, the mutational pattern of cancers of the different European countries shows remarkable differences, both in the site of the mutation (first or second base) and in the ratio of transitions over transversions. Moreover, a significant subgroup of pancreatic carcinomas do not harbor Ki-ras mutations. The classification of pancreatic cancers, according to the presence or absence, and type of Ki-ras mutation, may be of importance in epidemiological studies. A critical reappraisal of existing epidemiological data, through a retrospective genotypic study using paraffin-embedded cancer samples, may reveal significant correlations with specific genotoxic agents.

Preoperative diagnosis of renal angiomyolipoma: fine needle aspiration cytology and immunocytochemical characterization

A preoperative diagnosis of renal angiomyolipoma (AML) is of great importance for a correct management of these patients with this tumor. In fact when the lesion is small and asymptomatic a conservative approach may be considered. We have evaluated the radiographic and fine needle aspiration cytology (FNAB) findings in 8 cases of AML. In 3 cases both radiology and cytology were suggestive of carcinoma and thus the patients underwent surgery. In one case both techniques suggested AML but surgery was performed because the lesion was large and symptomatic. In 4 cases where both radiology and cytology suggested AML no surgery was performed. Follow-up data are consistent with the benign nature of the lesions. The immunocytochemical analysis of the FNAB with a panel of antibodies including keratin, vimentin, actin and HMB-45 was indicative of AML in 7 of 8 cases, including 2 of the 3 cases misdiagnosed as carcinomas. The presence of HMB-45-positive perivascular epithelioid cells in the FNABs was the most significant finding. It is concluded that immunocytochemical analysis of FNAB with this monoclonal antibody panel can increase the accuracy of preoperative diagnosis of AML, and allow consideration of a conservative approach in selected cases.

Pancreatic adenocarcinomas frequently show p53 gene mutations

Thirty-four pancreatic adenocarcinomas were studied for the presence of p53 gene mutations by the single-strand conformation polymorphism method and by direct sequencing of PCR-amplified fragments. p53 protein expression was immunohistochemically evaluated using monoclonal PAb1801 and polyclonal CM1 antibodies. Mutations were detected in 14 cases. The transitions were six G to A and two A to G; the transversions were one C to G and two A to C; the remaining three were frameshift mutations. Immunostaining results were identical with both antibodies. Nuclear immunohistochemical p53-positive cells were found in nine p53 mutated cases and in 12 cases in which no mutation was detected. In most of these latter cases only a minority of cancer cells showed immunohistochemical positivity. Twenty-nine cases, including all p53 mutated cancers, were known to contain codon 12 Ki-ras gene mutations. Also in the light of the demonstrated cooperation of ras and p53 gene alterations in the transformation of cultured cells, our data suggest that p53 mutation is one of the genetic defects that may have a role in the pathogenesis of a proportion of pancreatic cancers.

Neoplasia of the ampulla of Vater. Ki-ras and p53 mutations

Eleven tumors of the ampulla of Vater (5 stage IV and 2 stage II adenocarcinomas, 1 stage II papillary carcinoma, 1 neuroendocrine carcinoma, and 2 adenomas, one with foci of carcinoma) were examined for Ki-ras and p53 gene mutations by single-strand conformation polymorphism analysis and direct sequencing of polymerase chain reaction-amplified DNA fragments. Ki-ras mutations were found in one adenocarcinoma and in the adenoma with foci of carcinoma, both involving mainly the intraduodenal bile duct component of the ampulla. Seven cases showed p53 gene mutations: four advanced-stage adenocarcinomas, the papillary carcinoma, the neuroendocrine carcinoma, and the adenoma with foci of carcinoma. Nuclear accumulation of p53 protein was immunohistochemically detected in the morphologically high-grade areas of the five cancers harboring a p53 gene missense point mutation. The adenomas, the two frame shift-mutated cancers, and the adenomatous and low-grade cancer areas of mutated carcinomas were immunohistochemically negative. Our data suggest that in ampullary neoplasia 1) p53 mutations are common abnormalities associated with the transformation of adenomas and low-grade cancers into morphologically high-grade carcinomas, and 2) Ki-ras mutations are relatively less frequent and might be restricted to tumors originating from the bile duct component of the ampulla.

Chondroblastoma of the temporal bone. Case report

A case of chondroblastoma of the temporal bone in a 53-year-old male patient is presented. The diagnostic and therapeutic processes are discussed.

Evidence of c-myc gene abnormalities in mediastinal large B-cell lymphoma of young adult age

Six cases of mediastinal large B-cell lymphoma (MLCL) with sclerosis were analyzed for the presence and patterns of c-myc and bcl-2 loci rearrangements, and for the presence of Epstein-Barr virus DNA sequences by Southern blot hybridization, c-myc gene alterations were found in three of six cases. Two cases showed the presence of mutations or small rearrangements at the 3' end of the first exon. The c-myc gene abnormalities found in these two cases are similar to those observed in the translocation 8;14 of the endemic Burkitt's lymphomas or in its variants t(2;8) and t(8;22). A third case showed a major rearrangement of c-myc gene, with truncation within its first intron, similar to those observed in sporadic Burkitt's and in acquired immunodeficiency-associated lymphomas. None of the cases displayed bcl-2 gene rearrangements or contained viral sequences. Our data suggest a possible role for a translocation-mediated c-myc activation in the pathogenesis of MLCL. Conversely, bcl-2 gene and Epstein-Barr virus do not appear to be involved in the pathogenesis of these peculiar lymphomas. The association between c-myc structural modifications and MLCL also seems to be of relevance in light of the peculiar tendency of this tumor to involve unusual extranodal site (eg, kidney), reminiscent of the spreading attitude of Burkitt's limphomas.

Expression and gene rearrangement of the T-cell receptor in human thymomas

Human thymomas are epithelial neoplasms frequently associated with an exuberant lymphoid component. This mixture of epithelial cells and lymphocytes closely mimicks the organization of normal thymic cortex. However, it is not known whether thymocytes in thymoma express the T-cell receptor (TCR) for the antigen. We have analyzed the molecular configuration of TCR genes and their phenotypic expression in eight thymomas. In all we detected polyclonal rearrangements of TCR genes and cytoplasmic expression of TCR molecules in most thymocytes, thus indicating that rearranged TCR genes in thymomas are functioning genes. In addition, these findings suggest that the epithelial component of thymomas, even if neoplastic, is still capable of directing thymocyte differentiation.

Dissection of the thoracic aorta following partial clamping

A case is reported in which an extensive dissection of the thoracic aorta was observed after partial clamping during surgery on that blood vessel. The unfavourable outcome of the operation and the accurate investigation of the post-mortem material suggest a lesion of the artery wall secondary to tangential clamping by Satinsky's clamp. The possible pathogenetic mechanisms of lesions induced by vascular clamping are also discussed.

Evidence of pulmonary tropism of bamifylline and its main active metabolite

The extent of the extraplasmatic tropism of bamifylline (Bamifix) was evaluated in the rat and in man by assaying concentrations of bamifylline and of its main active metabolite AC-119 in lung tissue and plasma. After a single oral and intravenous administration of bamifylline in the rat, the ratio between pulmonary and plasma concentrations was between 2.0 and 3.2 for bamifylline, and between 4 and 15 for AC-119 during the observation period considered. On the other hand, the same ratios, calculated after the oral and intravenous administration of theophylline, ranged between 0.20 and 0.39. In studies on man, samples of plasma and lung tissue were obtained during surgery in subjects affected by pulmonary neoplasia and previously subjected to therapy with bamifylline according to the usual dosage scheme. The ratios between tissue and plasma concentrations, at the steady-state and in conditions of equilibrium between the compartments, were 9.4 for bamifylline and 34.7 for its active metabolite. The particular tissue tropism of bamifylline, that appears to be due to its high lipophilic character, could partly explain its high therapeutic index.

Increased sensitivity to protein kinase C activation in aortas of spontaneously hypertensive rats

The aortic muscle of spontaneously hypertensive (SHR) and normotensive control (WKY) rats was stimulated with phorbol esters and the contractile response was measured as isometric tension. Phorbol esters are known activators of protein kinase C. The aortas of SHR were characterized by the following distinct alterations in the response to phorbol myristate acetate: (1) increased sensitivity: half-maximal force was achieved at 62 +/- 6 nmol/l phorbol myristate acetate in SHR and 105 +/- 8 nmol/l in WKY; (2) increased contractility: the maximal force developed by phorbol myristate acetate was greater in SHR aortas (1.9 +/- 0.3 versus 1.6 +/- 0.2 g in WKY) compared with the decreased contractility generated with noradrenaline and high levels of potassium; (3) decreased dependency on extracellular calcium for half-maximal tension: in the presence of 3 mumol/l phorbol myristate acetate 50% of maximal force was attained at 21 +/- 8 mumol/l extracellular calcium compared with 49 +/- 9 mumol/l in WKY; (4) diminished relaxation in response to excess extracellular calcium: phorbol myristate acetate-precontracted WKY aortas began to relax when calcium was raised above 4 mmol/l in the bath and relaxation reached 51% at 8-10 mmol/l. Relaxation was almost absent in SHR (3-7%). Hence, there is an abnormality in the response to protein kinase C activation by phorbol esters in SHR vascular smooth muscle. Intracellular calcium appears to be involved. Studies of protein kinase C will prove important in understanding vascular smooth muscle function in normal and abnormal states.