Pancreatoduodenal carcinoma: a clinicopathologic study of 304 patients and immunohistochemical observation for CEA and CA19-9

A total of 304 patients with pancreatoduodenal carcinoma were studied clinicopathologically and immunohistochemically in order to clarify features of carcinoma of four different sites of origin; carcinoma of the ampulla of Vater (Am), the distal common bile duct (DCBD), the head of the pancreas (PH), and the extra-ampullary duodenum (Du). The mean greatest diameter of 87 PH was 3.5 cm compared with 2.7 cm of 149 Am and 2.7 cm of DCBD. Histopathologically, 40% of Am were papillary adenocarcinoma, while about half of DCBD, PH and Du were tubular adenocarcinoma. PH invaded lymphatic (85%), vascular (62%), and perineural (95%) spaces and metastasized lymph nodes (72%) more frequently than Am (77%, 35%, 24%, 50%), DCBD (47%, 61%, 65%, 45%), and Du (76%, 29%, 35%, 65%), respectively. More than 50% of PH invaded the resected margins, whereas in only 2% of Am, the surgical margins were affected by malignant cells. Immunohistochemically, PH was more frequently positive for both carcinoembryonic antigen (CEA) (98%) and carbohydrate antigen (CA) 19-9 (91%) than Am (83%, 62%), DCBD (94%, 58%), and Du (56%, 11%), respectively. The stromal staining type of CEA and CA 19-9 was more frequently seen in PH (27%, 44%) than in Am (9%, 31%), DCBD (11%, 8%) and Du (0%, 0%), showing a more dedifferentiated nature of PH. The cumulative 3-year survival rate of 87 patients with PH (15%) was worse than that of 149 with Am (42%, P less than 0.001), of 51 with DCBD (25%) and of 17 with Du (58%, P less than 0.001). The survival curve of 87 with PH was worse than that of 51 with DCBD, of 149 with Am (P less than 0.001) and of 17 with Du (P less than 0.001). Cox regression analysis, using eleven profound prognostic variables, revealed that venous invasion, perineural infiltration, surgical margin, and histopathologic type were profound prognostic factors. Pancreatic carcinoma has a more dedifferentiated histopathologic nature, showing a more aggressive growth and fares worse than Am, DCBD, and Du.

Cloning and sequencing of the gene encoding Toho-2, a class A beta-lactamase preferentially inhibited by tazobactam

Escherichia coli TUM1083, which is resistant to ampicillin, carbenicillin, cephaloridine, cephalothin, piperacillin, cefuzonam, and aztreonam while being sensitive to cefoxitin, moxalactam, cefmetazole, ceftazidime, and imipenem, was isolated from the urine of a patient treated with beta-lactam antibiotics. The beta-lactamase (Toho-2) purified from the bacteria hydrolyzed beta-lactam antibiotics such as penicillin G, carbenicillin, cephaloridine, cefoxitin, cefotaxime, ceftazidime, and aztreonam and especially had increased relative hydrolysis rates for cephalothin, cephaloridine, cefotaxime, and ceftizoxime. Different from other extended-spectrum beta-lactamases, Toho-2 was inhibited 16-fold better by the beta-lactamase inhibitor tazobactam than by clavulanic acid. Resistance to beta-lactams was transferred by conjugation from E. coli TUM1083 to E. coli ML4909, and the transferred plasmid was about 54.4 kbp, belonging to the incompatibility group IncFII. The cefotaxime resistance gene for Toho-2 was subcloned from the 54.4-kbp plasmid. The sequence of the gene was determined, and the open reading frame of the gene was found to consist of 981 bases. The nucleotide sequence of the gene (DDBJ accession no. D89862) designated as bla(toho) was found to have 76.3% identity to class A beta-lactamase CTX-M-2 and 76.2% identity to Toho-1. It has 55.9% identity to SHV-1 beta-lactamase and 47.5% identity to TEM-1 beta-lactamase. Therefore, the newly isolated beta-lactamase designated as Toho-2 produced by E. coli TUM1083 is categorized as an enzyme similar to Toho-1 group beta-lactamases rather than to mutants of TEM or SHV enzymes. According to the amino acid sequence deduced from the DNA sequence, the precursor consisted of 327 amino acid residues. Comparison of Toho-2 with other beta-lactamase (non-Toho-1 group) suggests that the substitutions of threonine for Arg-244 and arginine for Asn-276 are important for the extension of the substrate specificity.

Significance of postnatal mother-to-child transmission of human T-lymphotropic virus type-I on the development of adult T-cell leukemia/lymphoma

In order to shed light on the mode of HTLV-I infection by mother-to-child transmission, we examined sera of school children in a highly endemic town on two separate occasions at a 6-year interval. The carrier rates in ages 15-17, 8.7 and 2.1%, were significantly higher than that in ages 6-8, 1.7 and 0.4%, in studies. The latter survey showed a significantly lower carrier rate in each age group. Moreover, the carrier rates of those students born in 1965-1967 and 1968-1970 were stable in the interval. The data suggested that carrier rates of children at certain ages are reflected by the date of birth rather than by age. A prospective survey of children born of carrier mothers found the overall carrier rate to be approximately 25%, which did not increase with their age. There was no sexual difference in the carrier rate of children: 5/25 in male and 9/34 in females (X2 = 0.3). Carrier mothers could be separated into two groups: HTLV-I antigen-positive mothers and negative mothers. Nine out of 19 antigen-positive mothers (47%) and 2 of 19 antigen-negative mothers (11%) had carrier children (X2 = 6.3). Twelve of 30 children born of antigen-positive carrier mothers (40%) were carriers, in contrast to 2 of 24 children (8%) of antigen-negative mothers (X2 = 7.8). Furthermore, 12 of 14 carrier children (86%) were of antigen-positive mothers. This suggests that postnatal but early transmission of HTLV-I plays a significant role in the maintenance of HTLV-I endemy and the development of adult T-cell leukemia/lymphoma.

Operative treatment of syndesmotic disruptions without use of a syndesmotic screw: a prospective clinical study

A new protocol for the selected omission of transsyndesmotic fixation in Weber class C ankle fractures was prospectively evaluated in 21 consecutive patients. As proposed in a previous cadaveric study (J. Bone Joint Surg., 71A:1548-1555, 1989), the protocol suggested that transsyndesmotic fixation was not required if (1) rigid bimalleolar fracture fixation was achieved or (2) lateral without medial fixation was obtained (i.e., with accompanying deltoid tears) if the fibular fracture was within 4.5 cm of the joint. According to this protocol, only 3 of 21 patients (14%) required transsyndesmotic fixation. Ten of the patients who did not receive transsyndesmotic fixation underwent pronation-external rotation stress radiographs in a fashion analogous to the previous cadaveric study. At 1- to 3-year follow-up, no stress (N = 10) or static view (N = 18) widening of the mortise or syndesmosis was seen in any patient, which supports (with the above guidelines) a limited, rather than routine, use of supplemental transsyndesmotic fixation. Clinical results from this prospective study seem to substantiate previously proposed biomechanical guidelines for the selected omission of transsyndesmotic fixation. Given these guidelines, transsyndesmotic fixation was unnecessary in many cases and the need can be determined before surgery by assessing the integrity of the deltoid ligament and level of the fibular fracture.

Isolation of glucagon-secreting cell lines by cloning insulinoma cells

Six glucagon-secreting cell lines designated as In-R1-G1, -G3, -G7, -G9, -G10, and -G11 were isolated from insulinoma cells (In-111-R1) by single cell cloning. A small amount of insulin was also detectable in the incubation medium when hormone secretion was stimulated by the addition of arginine or theophylline. These cell lines grew as monolayers and the population doubling times varied from 16.8 to 28.8 h. Karyologically these clones were aneuploid and the modes of chromosome numbers were 61 to 70. Electron microscopic examination of one of these clones showed that these cells contained moderately developed Golgi apparatus and a few secretory granules, which more or less resembled alpha-cell granules. By gel filtration study of the incubation medium, glucagon and glucagonlike material were eluted. The molecular weight of the latter was approximately 9000, which suggested the concomitant secretion of proglucagon into the medium. The levels of secreted glucagon in basal state were 0.3 to 3.0 ng/10(6) cells/2 h. Glucagon secretion was markedly enhanced in the presence of amino acids. Glucagon secretion increased slightly in the presence of high concentration of glucose in Hanks' balanced salt solution; however it was not affected by the varying concentrations of glucose when the cells were incubated in complete media with amino acids. Glucagon secretion was also stimulated by the addition of theophylline. These clonal cell lines seem to provide a useful tool for investigating the mechanism of glucagon secretion.

Laparoscopic pancreatic surgery: current indications and surgical results

BACKGROUND

Although minimally invasive surgery has achieved worldwide acceptance in various fields, laparoscopic surgery for pancreatic diseases has been reported only rarely. The purpose of this study was to evaluate the outcomes and feasibility of laparoscopic pancreatic surgery.

METHODS

Fifteen patients, comprising eight men and seven women with an average age of 54 years, underwent laparoscopic pancreatic surgery. Distal pancreatectomy was indicated for solid tumors ( n = 4), cystic lesions ( n = 3), and chronic pancreatitis ( n = 2). Cystogastrostomy was performed for pseudocysts ( n = 4) and enucleation for insulinomas ( n = 2). The lesions varied in size from 1 to 9 cm (2.9 +/- 2.4 cm) and were located in the pancreatic head ( n = 2), body ( n = 3), or tail ( n = 10). For distal pancreatectomy, the splenic artery was divided and the parenchyma was transected with a linear stapler. Laparoscopic ultrasonography was used to determine the distance between the tumor and the main pancreatic duct for enucleation as well as to localize the lesion for distal pancreatectomy. Cystogastrostomy, 4.5 cm in length, was also performed with the linear stapler through the window of the lesser omentum.

RESULTS

Mean operation time was 249 +/- 70 min (293 +/- 58 min in distal pancreatectomy, 185 +/- 14 min in enucleation, 204 +/- 50 min in cystogastrostomy), and mean blood loss was 138 +/- 184 g (213 +/- 227 g, 75 +/- 35 g, 38 +/- 48 g, respectively). Two distal pancreatectomies (13%) were converted to open surgery due to severe peripancreatic inflammation. There was no related mortality, but there were two cases (15%) of pancreatic fistula, one in a distal pancreatectomy case and the other in an enucleation case, and both were treated conservatively.

CONCLUSIONS

Laparoscopic pancreatic surgery is safe and feasible for patients with benign tumors and cystic lesions.

NE-100, a novel sigma receptor ligand: in vivo tests

It has been suggested that sigma receptor antagonists may be useful as antipsychotic drugs. N, N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]-ethylamine monohydrochloride (NE-100) is a novel compound with high affinity for the sigma receptor (IC50 = 4.16 nM), but low affinity (IC50 > 10,000 nM) for D1, D2, 5-HT1A, 5-HT2 and phencyclidine (PCP) receptors. The head-weaving behavior induced by either (+)SKF10047 or PCP was dose-dependently antagonized by NE-100 with oral ED50 at 0.27 and 0.12 mg/kg, respectively. NE-100 did not affect dopamine agonists-induced stereotyped behavior and/or hyperactivity. NE-100 failed to induce catalepsy in rats. These findings indicate that NE-100 may have antipsychotic activity without the liability of motor side effects typical of neuroleptics.

Alterations of the PPP2R1B gene located at 11q23 in human colorectal cancers

BACKGROUND/AIMS

In 1998 the PPP2R1B gene encoding the A subunit of the serine/threonine protein phosphatase was identified as a putative tumour suppressor gene in lung and colon cancer in the chromosome region 11q22-24. The aim of the present study was to determine the type of alterations in primary rectal cancers as well as colon cancers and the correlation between these alterations and clinicopathological data.

METHODS

Mutation analyses of the PPP2R1B gene sequence encoding the binding sites of the catalytic C subunit (Huntington elongation A subunit TOR (HEAT) repeats 11-15) and partial binding sites of the regulatory B subunit were carried out on cDNA samples from 30 primary colorectal cancer specimens and corresponding normal tissues using a combination of the polymerase chain reaction and subsequent direct DNA sequencing.

RESULTS

Five missense mutations producing amino acid substitutions were detected in the four colon cancer cases (13.3%; four of 30 colorectal cancers): (15)glycine (GGT) to alanine (GCT) and (499)leucine (TTA) to isoleucine (ATA) in the same case, and (498)valine (GTG) to glutamic acid (GAG), (500)valine (GTA) to glycine (GGA), and (365)serine (TCT) to proline (CCT). Of these five mutations, three (60%) were located in HEAT repeat 13 and four (80%) showed T to other nucleotide substitutions. In addition, a normal polymorphism, (478)leucine, was found. No correlation was found between these mutations and clinicopathological data.

CONCLUSION

Our results suggest that the PPP2R1B gene is one of the true targets at 11q23, and its inactivation is involved in the development of all types of colorectal cancers.

Crystal structure of the E166A mutant of extended-spectrum beta-lactamase Toho-1 at 1.8 A resolution

Bacterial resistance to beta-lactams is mainly due to the production of beta-lactamase. Especially through the production of extended-spectrum beta-lactamases (ESBLs), bacteria have acquired resistance not only to penicillins, but also to expanded-spectrum cephems. Here, we describe the crystal structure of the E166A mutant of class A beta-lactamase Toho-1 at 1.8 A resolution, the first reported tertiary structure of an ESBL. Instead of the wild-type enzyme, a mutant Toho-1, in which Glu166 was replaced with alanine, was used for this study, because of the strong tendency of the wild-type enzyme to form twinned crystals. The overall structure of Toho-1 is similar to the crystal structures of non-ESBLs, with no pronounced backbone rearrangement of the framework. However, there are some notable local changes. First, a difference in the disposition of an arginine residue, which is at position 244 in non-ESBLs but at position 276 in Toho-1 and other ESBLs, was revealed and the role of this arginine residue is discussed. Moreover, changes in the hydrogen-bonding pattern and in the formation of the hydrophobic core were also observed near the Omega loop. In particular, the lack of hydrogen bonds in the vicinity of the Omega loop could be a cause of the extended substrate specificity of Toho-1. Through the generation of a model for the enzyme-substrate complex, a conformational change of Toho-1 occurring on complex formation is discussed based on the active-site cleft structure and the substrate profile.

MRI of groove pancreatitis

PURPOSE

The purpose of this work is to describe the findings on MRI in patients with groove pancreatitis, a specific form of chronic pancreatitis affecting the groove between the pancreatic head, the duodenum, and the common bile duct.

METHOD

MR images, including MR cholangiopancreatography, of five patients with groove pancreatitis were reviewed. Three patients underwent pancreatoduodenectomy due to serve duodenal stenosis, and the MR findings were compared to the histologic findings.

RESULTS

A sheet-like mass was demonstrated between the pancreatic head and the duodenum in all patients. The masses were hypointense relative to pancreatic parenchyma on T1-weighted images and iso- to slightly hyperintense on T2-weighted images. After administration of Gd-DTPA, the masses showed delayed enhancement. Histologically, fibrous scar tissue was detected in the groove.

CONCLUSION

MR images can clearly demonstrate the fibrous tissue in the groove in groove pancreatitis, and MR cholangiopancreatography can also provide useful information.

Structural features of aliphatic N-nitrosamines of 7-azabicyclo[2.2.1]heptanes that facilitate N-NO bond cleavage

N-Nitrosamines can be considered as potential nitric oxide (NO)/nitrosonium ion (NO(+)) donors. However, the relation of the structures of N-nitrosamines, in particular of aliphatic N-nitrosamines, to the characteristics of release of NO or NO(+) remains unclear. Here we show that aliphatic N-nitrosoamines of 7-azabicyclo[2.2.1]heptanes can undergo heterolytic N-NO bond cleavage. On the basis of the observation of reduced rotational barriers of the N-NO bonds in solution and nitrogen-pyramidal structures of the N-nitroso group in the solid state, we postulate that N-NO bond cleavage of N-nitrosamines is enhanced by a reduction of the resonance in the N-NO group. Computational studies suggest that these structural features of the N-nitrosamines of 7-azabicyclo[2.2.1]heptane are derived from angle strain imposed on the CNC angles.

Spontaneous in vivo reversion of an inherited mutation in the Wiskott-Aldrich syndrome

The Wiskott-Aldrich syndrome (WAS) is an X-linked primary immunodeficiency disease, arising from mutations of the WAS-protein (WASP) gene. Previously, we have reported that mononuclear cells from WAS patients showed lack/reduced of the intracellular WASP (WASP(dim)) by flow cytometric analysis, and analysis of WASP by flow cytometry (FCM-WASP) was useful for WAS diagnosis. In this study, we report a WAS patient who showed the unique pattern of FCM-WASP. The patient had the small population of normal expression of WASP (WASP(bright)) mononuclear cells together with the major WASP(dim) population. The WASP(bright) cells were detected in T cells, not in B cells or in monocytes. Surprisingly, the molecular studies of the WASP(bright) cells revealed that the inherited mutation of WASP gene was reversed to normal. His mother was proved as a WAS carrier, and HLA studies and microsatellite polymorphic studies proved that the WASP(bright) cells were derived from the patient himself. Therefore, we concluded that the WASP(bright) cells were resulted from spontaneous in vivo reversion of the inherited mutation. Furthermore, the scanning electron microscopic studies indicated that WASP-positive cells from the patient restored the dense microvillus surface projections that were hardly observed in the WASP(dim) cells. This case might have significant implications regarding the prospects of the future gene therapy for WAS patients.

New bronchoscopic microsample probe to measure the biochemical constituents in epithelial lining fluid of patients with acute respiratory distress syndrome

OBJECTIVE

A noninvasive bronchoscopic microsampling (BMS) probe was developed to sample biochemical constituents of the epithelial lining fluid in small airways.

DESIGN

Observational, controlled study.

SETTING

Intensive care unit of academic medical center. PATIENTS AND PROCEDURE: BMS was applied in a control group of seven patients who had hemoptysis or small solitary peripheral nodules but no hypoxemia or other signs of acute inflammation and in four patients with acute respiratory distress syndrome (ARDS), to test whether BMS can ascertain the presence of acute pulmonary inflammation without complications.

MEASUREMENTS AND RESULTS

Complications, including a significant decrease in arterial oxygen saturation, were observed neither during nor after BMS. In the ARDS group, albumin, lactate dehydrogenase, interleukin-6, basic fibroblast growth factor, and neutrophil elastase concentrations in epithelial lining fluid were significantly higher (p <.0001, p =.012, p <.0001, p <.0001, and p <.0001, respectively) than in the control group. Serial BMS was safely performed in one patient with ARDS, allowing us to observe a correlation between changes in the concentration of inflammation-related biochemical markers and clinical course of the disease.

CONCLUSIONS

These results suggest that BMS is safe and useful to monitor pulmonary biochemical events in ARDS.

Groove pancreatitis masquerading as pancreatic carcinoma

The clinicopathologic and radiologic features of groove pancreatitis masquerading as pancreatic carcinoma in eight Japanese patients were reviewed. All patients were men with a mean age of 58 years. Three patients complained of abdominal pain whereas others had jaundice. The jaundice fluctuated in one patient. Four patients had several episodes of pancreatitis, and four patients were alcoholics. Radiologically, a duodenal stricture was evident in five patients, biliary stenosis in six, pancreatic duct stenosis in four, and a mass in the pancreatic head in six. The biliary stenosis was characterized by smooth tapering, which improved after biliary drainage in three cases. Of the four patients who underwent angiography, two showed an encasement of vessels, one a hypervascular mass, and the other no abnormality. All patients underwent a pancreatoduodenectomy for suspected pancreatic carcinoma. However, the histopathologic diagnosis was chronic pancreatitis confined to the groove between the distal common bile duct, duodenum, and pancreas. The duodenum showed scarring and hyperplasia of the Brunner's gland. The biliary stenosis was produced by fibrosis and chronic inflammation around the distal common bile duct. Groove pancreatitis presents various clinical features, such as biliary obstruction, duodenal stenosis, and pancreatic mass, and often masquerades as pancreatic head carcinoma. This condition should be kept in mind when making a diagnosis of pancreatic head carcinoma to avoid an unnecessary radical operation.

Antigenicities of Group I and II hepatitis C virus polypeptides--molecular basis of diagnosis

Comparative nucleotide sequence studies on the putative NS3 and NS4 regions of the genomes of hepatitis C viruses (HCV) have revealed that there are at least two groups of HCV, group I and group II. The cDNA clone E, corresponding to a boundary between the NS3 and NS4 (NS3-4) region of the group II HCV genome, encodes antigens that react to antibodies specific to group II HCV (Tsukiyama-Kohara et al. (1991) Virus Genes 5, 243-254). To understand the molecular basis of the group-specific antigenicity of HCV peptides, the predicted amino acid sequences around the NS3-4 region of our group II HCV cDNAs were compared with those of other HCV isolates. The analysis revealed the presence of group-specific amino acids in this peptide region. Evolutionary analysis of nucleotide sequences within this region of these HCV isolates also led to the same classification. A similar result was obtained by sequence analysis of cloned cDNAs corresponding to the core region. A cDNA of the group II HCV core region was prepared by polymerase chain reaction from the cDNA synthesized with group II-specific primer complementary to the NS3-4 region. The products directed by the cDNA of the core region did not have group-specific antigenicity. The NS3 peptide region also appeared not to carry group-specific antigens. Our results indicate that most HCV isolates can be classified into either group I or II, and that the existence of two groups of HCV does not disturb HCV diagnosis as long as core and/or NS3 peptides are used to detect HCV antibodies.

Undifferentiated carcinoma of the gallbladder. A clinicopathologic, histochemical, and immunohistochemical study of 21 patients with a poor prognosis

Among 284 cases of carcinoma of the gallbladder, 21 were identified as undifferentiated carcinoma (UC), with little glandular or other specific epithelial differentiation. These tumors were classified into three histologic types according to the components: (1) small cell type (eight cases); (2) pleomorphic cell type (eight cases); and (3) spindle cell or pseudosarcomatous type (five cases). Histochemical and immunohistochemical study by the immunoperoxidase technique revealed that most of the tumors (13/21) contained mucosubstances, and that all examples of the UC were immunoreactive for epithelial membrane antigen (EMA), keratin, and carcinoembryonic antigen (CEA), thereby indicating the epithelial nature of the neoplastic cells. Vimentin immunoreactivity was found in nine tumors. In 19, the tumor contained various neoplastic endocrine cells, including somatostatin-immunoreactive (14/19), gastrin-immunoreactive (14/19), human chorionic gonadotropin (HCG)-immunoreactive (9/19), pancreatic polypeptide-immunoreactive (4/19), and serotonin-immunoreactive cells (4/19). The prognosis of patients with UC of the gallbladder was poorer than that of patients with differentiated adenocarcinoma.

Pulmonary complications in patients with adult T-cell leukemia

A survey of 360 patients with various hematologic diseases revealed a high frequency of respiratory complications in patients with adult T-cell leukemia (ATL) compared to others. Among 29 patients with ATL, pulmonary complications were seen in 26 patients; leukemic pulmonary infiltration in 13, bleeding in 1, interstitial pneumonitis in 1, and pulmonary infection in 13. The incidence of Pneumocystis carinii and bacterial pneumonias were high despite adequate neutrophil count. Even in chronic and smoldering ATL, respiratory diseases were found in high frequency. Many of those were leukemic cell infiltration. In ten of 13 patients with pulmonary infiltration it occurred in the early stage and 6 of them were diagnosed as having "chronic lung disease" before the diagnosis of ATL. Its histology was accompanied by fibrosis in greater or lesser degree in almost all cases. Transbroncheal lung biopsy (TBLB) is of value in diagnosis (8 of 13 cases).

Genetic polymorphism in matrix metalloproteinase-9 and pulmonary emphysema

Protease-antiprotease imbalance due to genetic variation may be responsible for the development of pulmonary emphysema induced by smoking. Since matrix metalloproteinases (MMPs) have recently been suggested to play important roles in the pathogenesis of pulmonary emphysema, the association between the functional polymorphism of MMP-9 (-1562C/T) and the development of pulmonary emphysema was examined in 110 smokers and 94 nonsmokers in Japan. The T allele frequency was higher in subjects with distinct emphysema on chest CT-scans (n = 45) than in those without it (n = 65) (0.244 vs 0.123, P = 0.02). Logistic regression analysis demonstrated that the T allele is a risk factor for smoking-induced emphysema (odds ratio = 2.69, P = 0.02). DL(CO)/VA was lower (P = 0.02) and emphysematous changes were more conspicuous (P = 0.03) in subjects with C/T or T/T (n = 35) than in those with C/C (n = 75). These results suggest that the polymorphism of MMP-9 acts as a genetic factor for the development of smoking-induced pulmonary emphysema.

Modulation of inwardly rectifying channels by substance P in cholinergic neurones from rat brain in culture

1. Whole-cell recording was used to investigate the effects of substance P on cultured neurones from the rat nucleus basalis. 2. Brief applications of substance P produced a reduction, about 1 min in duration, of resting membrane conductance. The concentration producing a half-maximal effect was approximately 40 nM, with the continuous presence of substance P resulting in desensitization of the response. 3. The control current-voltage relation exhibited inward rectification over the voltage range -70 to -150 mV, and hyperpolarization produced a time-dependent decrease of current (inactivation). 4. The substance P-sensitive current, obtained by subtracting the current during the presence of the tachykinin from the control current, showed no time-dependent inactivation, though its current-voltage relation also revealed inward rectification, with the reversal potential being approximately equal to the potassium equilibrium potential, Vk. 5. The relation between the substance P-sensitive chord conductance and voltage could be fitted by a Boltzmann equation, with changes in [K+]o shifting this relation along the voltage axis roughly in parallel with the shift in Vk. The maximum conductance was proportional to [( K+]o). 6. Cs+ (0.1 mM) blocked the substance P-sensitive current in a voltage-dependent manner, with an equivalent valency for Cs+ of 1.9. Barium blockage of the substance P-sensitive current was less voltage dependent. 7. Replacement of external Na+ by tetramethylammonium (TMA+) ions reduced the substance P-sensitive current by only 18%. 8. These results indicate that substance P inhibits potassium channels with inward rectifier properties very similar to those of skeletal muscle. 9. Application of sodium nitroprusside did not alter the effect of substance P, suggesting that cyclic GMP plays no role in the channel modulation.

Shoulder sonography. State of the art

Since the mid 1980s, sonography has been used to evaluate the rotator cuff. It is inexpensive, well tolerated, rapidly performed, and accurate. With the recent improvements in imaging equipment and refinements in scanning technique, an increasing number of radiologists are performing shoulder sonography. This article emphasizes the pertinent musculoskeletal anatomy, sonographic technique, normal sonographic anatomy, pathophysiology of rotator cuff and biceps tendon disease, sonographic findings of rotator cuff tears, and biceps tendon pathology. The accuracy of ultrasound in diagnosing rotator cuff tears and miscellaneous abnormalities that can be detected with ultrasound also are discussed.