Traumatic basilar impression: case report

A very rare case of traumatic basilar impression is reported. The patient, a 57-year-old man, was hit on the head vertically in the parietal region. X ray of the cervical spine and computed tomography (CT) scans showed intracranial indentation of the atlas and the odontoid process with a depressed fracture around the foramen magnum. There are no previous reports about this type of fracture.

Different effects of subclasses of HDL containing apoA-I but not apoA-II (LpA-I) on cholesterol esterification in plasma and net cholesterol efflux from foam cells

We investigated the effects of subclasses of plasma LpA-I (HDL containing apoA-I but not apoA-II) on cholesterol esterification in plasma and net cholesterol efflux from foam cells. LpA-I was composed of particles of three diameters: large (11.1 nm; Lg-LpA-I), medium (8.8 nm; Md-LpA-I), and small (7.7 nm; Sm-LpA-I). Plasma concentrations of LpA-I were positively correlated only with the level of Lg-LpA-I. Plasma concentrations of Lg-LpA-I were inversely correlated with the rate of cholesterol esterification in plasma and VLDL- and LDL-depleted plasma. Plasma concentrations of Md-LpA-I and Sm-LpA-I did not correlate with the rate of cholesterol esterification in plasma or VLDL- and LDL-depleted plasma. When macrophage foam cells were incubated with Md- and Sm-LpA-I, cellular cholesterol mass was reduced by approximately 70%. In contrast, the cellular cholesterol-reducing capacity of Lg-LpA-I was negligible. Lg-LpA-I inhibited net cholesterol removal from foam cells that was mediated by Md- and Sm-LpA-I and cholesteryl ester production with these particles. These results suggest that Md- and Sm-LpA-I may actively participate in cellular cholesterol removal and cholesterol esterification in plasma and HDL, while Lg-LpA-I may regulate these functions of Md- and Sm-LpA-I.

Expression of pancreatic trypsinogen/trypsin and cathepsin B in human cholangiocarcinomas and hepatocellular carcinomas

We evaluated in situ expression of pancreatic trypsinogen (PT) and cathepsin B (CB) in 10 normal livers, 37 cholangiocarcinomas (CCs), and 36 hepatocellular carcinomas (HCCs). In normal livers, PT was expressed in intrahepatic large bile ducts, septal bile ducts, and peribiliary glands, and CB was present in hepatocytes and all epithelial cells of the intrahepatic biliary system. In CCs, PT was present in 26 (70%), of which 24 expressed PT both in CC cells and the CC stroma, and the remaining two showed PT only in CC cells. The ratio of PT-positive cases was high in well-differentiated CCs, moderate in moderately differentiated CCs, and low in poorly differentiated CCs. PT in the CC stroma was present in continuity with PT-positive CC cells, suggesting that PT was secreted from CC cells. The CC stroma positive for PT frequently showed destructive features. CB was present in 32 CCs (86%) and located in both CC cells and the CC stroma. All PT-positive CCs simultaneously expressed CB, suggesting a close association of PT and CB. In HCCs, in contrast, PT was not present in any cases. CB was present in 33 HCCs (92%) and located in both HCC cells and the HCC stroma. In positive specimens, PT immunoreactivity was finely granular in the cytoplasm, whereas CB immunoreactivity was diffuse in the entire cytoplasm. These data suggest that after malignant transformation CCs and HCCs continue to express PT and CB, and CB, respectively. It seems possible that PT secreted from CC cells is converted into trypsin by CB, and that trypsin and CB play a role in CC invasion by degrading extracellular matrix proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Cloning of a cDNA for DNA supercoiling factor reveals a distinctive Ca(2+)-binding protein

DNA supercoiling factor is a protein capable of generating negative supercoils into a relaxed DNA in conjunction with eukaryotic DNA topoisomerase II. A cDNA clone encoding the Bombyx mori supercoiling factor has been isolated and characterized. The cDNA sequence contains an open reading frame of 322 amino acids rich in acidic residues. A local region of the predicted polypeptide shares a weak homology with the central portion of bacterial DNA gyrase A subunit. The cDNA sequence also predicts two direct repeats within the factor. Each repeat unit consists of a potential EF-hand domain. The factor contains three other potential EF-hand domains and actually binds Ca2+. Moreover, the supercoiling reaction has been shown to be activated by Ca2+. These results implicate Ca2+ in the control of the superhelical state of DNA.

Metastasis-promoting activity of a novel molecule, Ag 243-5, derived from mycoplasma, and the complete nucleotide sequence

We found that mycoplasma-infected cells have a higher ability to metastasize in vivo than non-mycoplasma-infected cells. To investigate this phenomenon, we obtained a monoclonal antibody, MAb 243-5, by immunization with Mycoplasma arginini-infected RPMI 4788 cells. This MAb recognized a mycoplasmal protein with an MW of 47 kDa and completely inhibited the experimental metastasis of M. arginini-infected RPMI 4788 cells using a nude mouse model. Using this MAb, we purified a molecule called Ag 243-5 and determined the N-terminal amino acid sequence and clarified the entire nucleotide sequence of the Ag 243-5 gene. PCR analysis showed the existence of a homologous gene in Mycoplasma hyorhinis. Four sequential injections of Ag 243-5 (30 micrograms/shot) promoted the experimental metastasis of non-mycoplasma-infected RPMI 4788 cells more than 10-fold using a nude mouse model. Ag 243-5 also promoted the experimental metastasis of the non-mycoplasma-infected mouse colon cancer cell line colon 26. This metastasis-promoting effect was neutralized by MAb 243-5.

Surgical strategy for carcinoma of the pancreas head area based on clinicopathologic analysis of nodal involvement and plexus invasion

BACKGROUND

The pattern of tumor spread, vis-à-vis nodal involvement and invasion of the extrapancreatic plexus (Plx), has not been thoroughly described for carcinoma of the pancreatic head area.

METHODS

From 1973 to 1991, 110 patients (49 with carcinoma of the pancreatic head [Ph], 29 with distal bile duct cancer [Bi], and 32 with carcinoma of the papilla of Vater [Pv]) underwent pancreatectomy at Kanazawa University Hospital. Nodal involvement and Plx invasion were precisely evaluated by histopathologic examination.

RESULTS

Thirty-seven (76%) of the 49 patients with Ph, 20 (69%) of the 29 with Bi, and 14 (44%) of the 32 with Pv had nodal involvement. The lymph nodes most commonly involved for Ph were the posterior pancreaticoduodenal lymph nodes (numbers 13a [superior] and 13b [inferior]), the superior mesenteric lymph nodes (number 14), the paraaortic lymph nodes (number 16), and the anterior pancreaticoduodenal lymph nodes (number 17) (13a, 51%; 13b, 47%; 14, 36.7%; 16, 18.4%; 17a, 33%; 17b, 22%). In patients with Bi, lymph nodes around the hepatoduodenal ligament (number 12) and lymph nodes numbers 13a and 14 were most commonly involved (12, 27.6%; 13a, 51.7%; 14, 34.5%). In patients with Pv, lymph node numbers 13b and 14 were most frequently involved (13b, 34.4%; 14, 15.6%). No significant correlation was noted between the tumor size and nodal involvement in these three lesions. Nodal involvement was an important prognostic factor for carcinoma of the pancreatic head area. Plx invasion in these three carcinomas was observed in 61% of patients with Ph, 29% of patients with Bi, and 3% of patients with Pv.

CONCLUSIONS

Nodal involvement and Plx invasion differed significantly among carcinomas of the pancreatic head area. We believe that nodal dissection of at least group number 14 is needed for Ph, Bi, and Pv cancers. In addition, dissection of lymph nodes of number 16 and the Plx around the superior mesenteric artery and celiac axis are needed in Ph cancer. Plx dissection of the first portion of plexus pancreaticus capitalis is needed in Bi cancer.

Significance of urinalysis for subsequent kidney and urinary tract disorders in mass screening of adults

To evaluate dipstick urinalysis as a predictor of subsequent kidney and urinary tract disorders in apparently healthy adults, we designed a cross-sectional, prospective, and retrospective study within a cohort. The severity of proteinuria was significantly (p < 0.01) associated with the amount of pathological casts, whereas hematuria without proteinuria was not. The frequency of subsequent serum creatinine increase (0.3 mg/dl/5 years or more) was significantly enhanced (from 0.4% to 7.3% along with the severity of proteinuria, whereas it was not related to the severity of hematuria. Patients who subsequently developed renal failure and glomerulonephritis exhibited hematuria (11.1-32.1%) less frequent than proteinuria (62.3-83.3%). Even those with renal tumors or stones showed infrequent (14.3-27.9%) hematuria. Thus, urine protein and occult blood have different implications in mass screening.

[A study of infarction in the region of the anterior inferior cerebellar artery]

Sixteen patients with infarction in the region supplied by the anterior inferior cerebellar artery (AICA) were studied to assess the mechanism and its clinical features. Risk factors involved hypertension, diabetes mellitus, a history of cerebrovascular disease and hyperlipidemia in seven patients (44%), while smoking was found in six (38%). The pathogenesis of these patients was thought to be thrombotic in all 16 patients, and lesions of the vertebrobasilar system were noted in 7 out of 13 patients (54%) who underwent cerebral angiography. Gasperini syndrome (AICA syndrome+abducens paralysis) occurred in two patients (13%), and five patients (31%) showed only cerebellar ataxia (3 had infarction confined to the middle cerebellar penduncle and 2 had infarction confined to the cerebellar hemisphere). As a result of analysis of clinical symptoms in nine patients with the incomplete AICA syndrome, loss of hearing in six patients (67%) and cerebellar ataxia in all nine patients were noted. We postulated that large-artery occlusive disease or branch atheromatous disease resulted in an infarction in the region of the AICA. It is necessary to consider infarction of the AICA region in patients who present a unilateral hearing loss and cerebellar ataxia.

[A case of multilocular thymic cyst with myasthenia gravis]

We reported a case of 53-year-old male who was admitted to our hospital for ptosis and difficulty in chewing. Because of positive for Tensilon test and high dose anti-acetylcoline receptor antibody, we established diagnosis for myasthenia gravis. Additionally he was pointed out a cystic lesion at anterior superior mediastinum on CT and MRI. As a result we diagnosed him as thymic cyst with myastenia gravis. The extended thymectomy was performed. Histological examination revealed that the mass was a multilocular thymic cyst which is reported by Suster, who suggested that the multilocular thymic cyst arises from processes of reactions to an acquired inflammatory change. There was no report for cases of multilocular thymic cyst with myastenia gravis. MTC-like changes are sometimes presented in association with thymic Hodgkin's disease or thymic seminoma. Malignant transformation of thymic cyst were also reported. So careful examination and evaluation for cystic lesion within thymus are required.

[A case of Guillain-Barré syndrome associated with anti-GM2 antibody due to cytomegalovirus infection--special reference to the effect of ganciclovir]

We report a case of Guillain-Barré syndrome (GBS) associated with anti-GM2 antibody caused by cytomegalovirus (CMV) infection. A 27-year-old man was admitted to our hospital because of muscle weakness in all his extremities. He had no background of immunological abnormalities. Within 5 days, generalized muscular weakness had progressed so rapidly that he suffered respiratory dysfunction and dysphagia. Throughout the entire clinical course, enzyme immunoassay (serum) and enzyme-linked immunosorbent assay (CSF) for CMV were carried out serially. Only antibodies against CMV were elevated during the clinical course in the serum and CSF. These findings supported the idea that he had developed GBS due to isolated CMV infection. We examined the reactivity of GBS sera with crude ganglioside fraction, and only anti-GM2 antibody was recognized on a high-performance thin-layer chromatogram plate in this case. Although the anti-GM2 antibody was decreased transiently by plasmapheresis, the clinical symptoms progressed. The symptoms advanced very rapidly during high-dose gammaglobulin therapy associated with reelevation of the anti-GM2 antibody. Following ganciclovir administration, however, the symptoms became diminished within 7 days and the anti-GM2 antibody fell dramatically. We speculate that the reason for the observed effectiveness of ganciclovir was direct suppression of activation of CMV, followed by the inhibition of the production of demyelinating antibodies including the anti-GM2 antibody.

Phenytoin and fluoride act in concert to stimulate bone formation and to increase bone volume in adult male rats

We have recently demonstrated that phenytoin is an osteogenic agent at low doses. The present paper describes observations that a mitogenic dose (i.e., 20 microM in BGJb medium) of fluoride significantly augments the phenytoin-dependent stimulation of normal human bone cell proliferation and alkaline phosphatase (ALP) activity in cell culture. Additionally, the present study was designed to investigate whether fluoride and phenytoin would interact to increase bone formation in rats in vivo. Four groups of weight-matched adult male rats received daily I.P. injection of (1) vehicle (10% DMSO), (2) 5 mg/kg/day phenytoin, (3) 5 mg/kg/day phenytoin and 50 ppm NaF, and (4) 50 ppm NaF and vehicle, respectively, for 36 days. Sodium fluoride (NaF) was delivered in drinking water. Blood samples were drawn weekly and analyzed for serum osteocalcin, ALP, calcium, phosphorus, and 25(OH)D3. Rats were labeled with tetracycline at day 21 and 30 and histomorphometric analysis was carried out on the tibia at the end of the experiment. Neither agent by itself or together affected the serum calcium, phosphorus, or 25(OH)D3 levels. All measures of bone formation, i.e., serum osteocalcin level and ALP activity, bone ALP specific activity, mineral apposition rate, bone formation rate, and % bone formation surface, were increased by each agent. Fluoride and phenytoin together produced bigger increases in each parameter than did each agent alone. Trabecular bone volume was increased in the tibial metaphysis by fluoride or phenytoin alone; and when administered together, the two agents produced a greater increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of subspecies of lipoprotein containing apolipoprotein A-I in heterozygotes for familial lecithin:cholesterol acyltransferase deficiency

We characterized two species of lipoproteins containing apo A-I, one containing only apo A-I (LpA-I) and the other containing both apo A-I and apo A-II (LpA-I/A-II), in three heterozygotes for familial lecithin:cholesterol acyltransferase deficiency (LCAT). In these patients, particle size and the chemical composition of LpA-I differed from those in normal controls. Small particles < 8.8 nm in diameter were predominant, and protein content was higher in patients' LpA-I than that in normal LpA-I. Changes in LpA-I/A-II were mostly quantitative. Percent lipid and protein composition in LpA-I/A-II were similar to those in normal controls. Despite low LCAT mass and activity in the heterozygotes, the molar and fractional rate of cholesterol esterification in their LpA-I and LpA-I/A-II particles were similar to, or higher than, that of normal controls. We conclude that: (i) low LCAT mass and activity is the likely cause of the quantitative and qualitative differences in LpA-I in heterozygotes; and (ii) a deficiency of normal LpA-I particles 11.1 nm in diameter and the existence of small particles < 8.8 nm in diameter may be responsible for the normal, or higher than normal, cholesterol esterification rate of LpA-I and LpA-I/A-II in heterozygotes.

Human ribosomal RNA gene cluster: identification of the proximal end containing a novel tandem repeat sequence

Human ribosomal RNA genes (rDNA) are arranged as tandem repeat clusters on the short arms of five pairs of acrocentric chromosomes. We have demonstrated that a majority of the rDNA clusters are detected as 3-Mb DNA fragments when released from human genomic DNA by EcoRV digestion. This indicated the absence of the EcoRV restriction site within the rDNA clusters. We then screened for rDNA-positive cosmid clones using a chromosome 22-specific cosmid library that was constructed from MboI partial digests of the flow-sorted chromosomes. Three hundred twenty rDNA-positive clones negative for the previously reported distal flanking sequence (pACR1) were chosen and subjected to EcoRV digestion. Seven clones susceptible to EcoRV were further characterized as candidate clones that might have been derived from the junctions of the 3-Mb rDNA cluster. We identified one clone containing part of the rDNA unit sequence and a novel flanking sequence. Detailed analysis of this unique clone revealed that the coding region of the last rRNA gene located at the proximal end of the cluster is interrupted with a novel sequence of approximately 147 bp that is tandemly repeated and is connected with an intervening 68-bp unique sequence. This junction sequence was readily amplified from chromosomes 21 and 15 as well as 22 using the polymerase chain reaction. Fluorescence in situ hybridization further indicated that the approximately 147-bp sequence repeat is commonly distributed among all the acrocentric short arms.

[Lifestyles and renal damage--association of smoking, drinking and physical activity with subsequent proteinuria]

To examine the role of lifestyles in the subsequent development of renal damage, the association of smoking, drinking and physical activity with subsequent proteinuria was investigated utilizing a longitudinal study. The subjects were 7,701 males aged 20-84 years, who participated in health examinations at Aichi Prefectural Center of Health Care, Nagoya, Japan, both in 1989-1990 and 1992-1993, and who showed no proteinuria at the first examination. Lifestyles at the first examination were compared between 140 men with, and 7,561 men without, newly developed proteinuria at the second examination. Age-adjusted odds ratios (ORs) of lifestyle factors for proteinuria were computed, and further the ORs were adjusted for age, systolic blood pressure, fasting plasma glucose level and other covariates obtained using multiple logistic regression analysis. Major significant findings which emerged from the present study were as follows. (a) The greater the consumption of alcohol per day, the higher the risk of subsequent proteinuria (trend p = 0.003). Heavy drinkers who consumed more than 58 g of alcohol per day experienced an increased risk (OR relative to non-drinker: 2.52). (b) Those who exercised less than once a week, and those who avoided walking even a short distance were at an increased risk (OR: 1.46, 1.55, respectively). Heavy drinking and low physical activity were found to be significantly associated with an increased risk of subsequent proteinuria even after adjusting for the covariates. An increasing risk of subsequent proteinuria with number of cigarette smoked per day was observed by univariate and multivariate analysis but without statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hemodynamics of the transverse sinus using cine angiography]

Numerous anatomical observations of the transverse sinus (TS) have been reported and features of this sinus, as assessed by cerebral angiography, are referred to in many monographs. However, there are no studies on the hemodynamics in the TS. We recently investigated the TS, using cerebral angiography with cinematographic films. The subjects were 35 patients who underwent angiography of 3 or 4 vessels at our institute, using Seldinger's method. The contrast material was infused manually. Cinematography permitted observation of the size of the bilateral TS and the direction of blood flow. Depending on the features of the bilateral TS, the patients could be divided into three groups. Type I (cases where the right TS was dominant) accounted for the highest percentage (54.3%, 19/35). In 11 of these 19 cases, the left TS also showed antegrade blood flow. In 6 of the Type I group, the blood flow through the left TS was in two directions (towards the Torcular Herophili and towards the left sigmoid sinus). In the other two cases rated as Type I, the blood flow through the left TS was in the direction from the Torcular Herophili to the right TS. Fourteen cases (40.0%) were rated as Type II (in which both sinuses were similar in size). In 13 of these 14 cases, blood flow through the bilateral TS was almost symmetrical (Type II-A). In one of the 14 cases, the blood flow through the left TS was in two directions (towards the Torcular Herophili and towards the left sigmoid sinus).

[Risk of chromosomally unbalanced progeny in prenatal diagnoses of reciprocal translocation carrier]

To obtain new criteria for presuming the existence of chromosomally unbalanced progeny in reciprocal translocation carrier couples, the obstetrical histories of 57 couples were analysed. The chromosomally unbalanced progeny who had been prenatally or postnatally diagnosed were mainly partial trisomies. In contrast with partial trisomies, there were only a few cases of partial monosomies and there were only two cases of chromosomal imbalance derived from 3:1 segregation in gametogenesis. Moreover, the percentage of haploid autosome length (%HAL) of the maternal carriers whose progeny had suffered from chromosomal imbalance was significantly smaller than those of the maternal carriers who had not had progeny with chromosomal imbalance. Based on these results, the following criteria were obtained: 1) Partial trisomies tend to be maintained in pregnancy but partial monosomies do not; Most chromosomally unbalanced zygotes which were induced by 3:1 segregated gametes tend to be spontaneously selected in early pregnancy; 3) When interchanged segments of chromosomes are small in maternal reciprocal translocation carriers, chromosomally unbalanced fetuses tend to be maintained in pregnancy.

Nucleotide sequence of the FAD synthetase gene from Corynebacterium ammoniagenes and its expression in Escherichia coli

The nucleotides of a bifunctional enzyme FAD synthetase gene, which showed both flavokinase and ATP:FMN adenylyltransferase activities, from Corynebacterium ammoniagenes were sequenced. The FAD synthetase gene product consisted of 338 amino acids and had a calculated molecular weight of 37,712. The deduced protein sequence of the FAD synthetase shared a homology with those of the protein X of Escherichia coli, which has been reported to have both flavokinase and ATP:FMN adenylyltransferase activities like the FAD synthetase of C. ammoniagenes, and the protein X of Pseudomonas fluorescens. From the analysis of the flanking sequences of the FAD synthetase gene, the gene organization and the operon structure around the FAD synthetase gene of C. ammoniagenes were thought to be different from those of Gram-negative bacteria. An over-expression system of the FAD synthetase of C. ammoniagenes was constructed in E. coli to study the structure and function of the protein. Under the tandem tryptophan promoter, the FAD synthetase activity increased 2231 times compared to that of non-transformed C. ammoniagenes.

Evaluation of long-term survivors after pancreatoduodenectomy for pancreatoduodenal carcinoma

Long-term survivors (> or = 5 years) of pancreatoduodenal carcinoma were evaluated. The absence of retropancreatic invasion seemed to be an important factor for long-term survival in carcinoma of the pancreatic head, carcinoma of the intrapancretic bile duct confined within the bile duct wall, and stage II papilla of Vater carcinoma. The mode of infiltration was INF alpha or INF beta, with a low infiltration tendency. Lymph node metastasis, when present, was confined to the pancreatic head. It is noteworthy that two of the patients with intrapancreatic bile duct cancer had perineural infiltration to the pancreatic head plexus. In patients treated by extended resection, postoperative malnutrition and diarrhea was severe, indicating the importance of long-term nutritional management.

Structural composition of hammerhead ribozymes

Eleven kinds of hammerhead ribozymes were designed and synthesized to investigate the structural composition of the complexes and to find suitable crystallization conditions, the substrate chains having been modified to prevent hydrolysis. Electrophoresis patterns indicated that the two strands except for the substrate chain form a binary complex and that they form a ternary complex when mixed with the substrate chain. Both complexes were crystallized. The crystal of the binary complex belongs to a Laue symmetry of 32 (space group of P321, P3(1)21, or P3(2)21) with cell dimensions of a = b = 53.4 and c = 59.4 A. The volume per one nucleotide allows the asymmetric unit to contain one binary complex. Our results suggest that the catalytic part forms a rigid ribozyme structure which induces a scissile reaction when the substrate is bound, in a similar manner to an enzyme protein.

Structural and functional differences of subspecies of apoA-I-containing lipoprotein in patients with plasma cholesteryl ester transfer protein deficiency

ApoA-I-containing lipoproteins exist in plasma in two main forms: one contains only apoA-I (LpA-I) while the other contains both apoA-I and apoA-II (LpA-I/A-II). We characterized structural and functional changes of these lipoproteins in six patients with cholesteryl ester transfer protein (CETP) deficiency. In these patients, the amount of LpA-I and LpA-I/A-II had increased significantly. Sixty-five percent of plasma apoA-I was associated with LpA-I/A-II, which indicated that LpA-I/A-II was predominant. The chemical composition of both LpA-I and LpA-I/A-II was characterized by increased ratios of neutral to polar lipid, compared with findings in normal subjects. Particle sizes of these lipoproteins shifted to larger diameter ranges, as compared to the size seen in normal subjects. Incubation of patients' LpA-I and LpA-I/A-II with CETP markedly corrected the chemical and physical abnormalities in these lipoproteins. Cholesterol-reducing capacities of these lipoproteins from macrophage foam cells were significantly lower than in normal controls. Cholesterol esterification rates in LpA-I, LpA-I/A-II, and plasma were significantly lower in patients than in normal controls. We propose that the structure and function of LpA-I and LpA-I/A-II are severely affected in the presence of CETP deficiency.

Isolation and characterization of a novel gene deleted in DiGeorge syndrome

The region commonly deleted in DiGeorge syndrome (DGS) has been localized at 22q11.1-q11.2 with the aid of a high resolution banding technique. A 22q11 specific plasmid library was constructed with a microdissection and microcloning method. Dosage analysis proved three of 144 randomly selected microclones to detect hemizygosity in two patients with DGS. Two of the clones were found to contain independent low-copy-number repetitive sequences, all of which were included in the region deleted in the DGS patients. Screening of the cosmid library and subsequent cosmid walking allowed us to obtain two cosmid contigs corresponding to the microclones within the deletion (contig 1 and contig 2), whose order fluorescence in situ hybridization identified as centromere-contig 1-contig 2-telomere on 22q. By direct selection strategy using one of the cosmids of contig 1, a 4.3 kb cDNA was obtained from fetal brain cDNA library. Sequence analysis of the cDNA revealed an open reading frame encoding 552 amino acids which had several characteristics of DNA-binding proteins. The gene, designated LZTR-1, which was transcribed in several essential fetal organs, proved to be hemizygously deleted in seven of eight DGS patients or its variants, but not in one DGS patient and GM00980. Although LZTR-1 does not locate in the shortest region of overlap, several of its structural characteristics identifying it as transcriptional regulator suggest that it plays a crucial role in embryogenesis and that haploinsufficiency of this gene may be partly related to the development of DGS.

ATP-evoked membrane current in guinea pig adrenal chromaffin cells

Adenosine 5'-triphosphate (ATP) evoked an inward current in whole-cell voltage-clamped adrenal chromaffin cells of the guinea pig. The reversal potential (Erev) of ATP-evoked current was about 0 mV in normal external solution and was shifted towards negative potentials by substituting Tris+ or sucrose, but not Ca2+, for the extracellular Na+. This current was mediated by the activation of non-selective cation channels and had some different properties from nicotinic current. It is suggested that these channels may function as a part of the ATP-induced Ca2+ influx pathway in guinea pig chromaffin cells.