Molecular cytogenetic analysis of five newly established cervical cancer cell lines using G banding and fluorescence in situ hybridization

Cervical tumors nearly all have complex karyotypes and more precise cytogenetic information is required to establish whether specific rearrangements occur, and if they are related to the type of HPV infection found. The karyotypes of five recently established cervical cancer cell lines, three from squamous cell carcinomas (two HPV 16 +ve and one HPV 18 +ve), one from an adenocarcinoma (HPV -ve), and one from an adenosquamous carcinoma (HPV 16 +ve), have been analysed using fluorescence in situ hybridization (FISH), with 23 chromosome specific paints, YACs and cosmids as probes, in addition to conventional G banding, in order to identify markers and clarify the breakpoints. Chromosomes 1 and 3 were rearranged in all cell lines. Breakpoints in the squamous lines were all in 3q. but in different regions. Small metacentrics involving chromosome 5 were a del(5q) in one line, and a t(X;5) in another, rather than i(5p). The region 6q21 was involved in three cases and chromosome 9 was rearranged in four. An i(8q) was found in three squamous carcinoma cell lines. Structural changes of 11q were found only in two cases, but a marker 11 representing amplification in the 11q14-22 region was duplicated in the adenosquamous line.

Identification of a nonsense mutation in the carboxyl-terminal region of DNA-dependent protein kinase catalytic subunit in the scid mouse

DNA-dependent protein kinase (DNA-PK) consists of a heterodimeric protein (Ku) and a large catalytic subunit (DNA-PKcs). The Ku protein has double-stranded DNA end-binding activity that serves to recruit the complex to DNA ends. Despite having serine/threonine protein kinase activity, DNA-PKcs falls into the phosphatidylinositol 3-kinase superfamily. DNA-PK functions in DNA double-strand break repair and V(D)J recombination, and recent evidence has shown that mouse scid cells are defective in DNA-PKcs. In this study we have cloned the cDNA for the carboxyl-terminal region of DNA-PKcs in rodent cells and identified the existence of two differently spliced products in human cells. We show that DNA-PKcs maps to the same chromosomal region as the mouse scid gene. scid cells contain approximately wild-type levels of DNA-PKcs transcripts, whereas the V-3 cell line, which is also defective in DNA-PKcs, contains very reduced transcript levels. Sequence comparison of the carboxyl-terminal region of scid and wild-type mouse cells enabled us to identify a nonsense mutation within a highly conserved region of the gene in mouse scid cells. This represents a strong candidate for the inactivating mutation in DNA-PKcs in the scid mouse.

The human homolog T of the mouse T(Brachyury) gene; gene structure, cDNA sequence, and assignment to chromosome 6q27

We have cloned the human gene encoding the transcription factor T. T protein is vital for the formation of posterior mesoderm and axial development in all vertebrates. Brachyury mutant mice, which lack T protein, die in utero with abnormal notochord, posterior somites, and allantois. We have identified human T genomic clones and derived the mRNA sequence and gene structure. There is 91% amino acid identity between human and mouse T proteins overall and complete identity across 77 amino acids of the T-box motif within the DNA-binding domain. Human T expression is very similar to that found for T in other vertebrate species and is confined to cells derived from the notochord. The human T gene maps to chromosome 6q27 and is only the second human member of the T-box gene family to be described.

Locus control region function and heterochromatin-induced position effect variegation

Human CD2 locus control region (LCR) sequences are shown here to be essential for establishing an open chromatin configuration. Transgenic mice carrying an hCD2 mini-gene attached only to the 3' CD2 transcriptional enhancer exhibited variegated expression when the transgene integrated in the centromere. In contrast, mice carrying a transgene with additional 3' sequences showed no variegation even when the latter integrated in centromeric positions. This result suggests that LCRs operate by ensuring an open chromatin configuration and that a short region, with no enhancer activity, functions in the establishment, maintenance, or both of an open chromatin domain.

Multicentre clinical evaluation of the COBAS CORE CEA, CA 125 II and PSA tumor marker assays

The aim of our study was to evaluate the clinical usefulness of the tumor markers CEA, CA 125 and PSA using the COBAS CORE system from Roche Diagnostic Systems. Our results demonstrate that determination of these markers on the COBAS CORE immunoassay analyser provides the performance required for routine use in clinical practice. The results obtained in this clinical trial validate the correlation with disease extension, a characteristic that defines and determines the clinical utility of the tumor markers. We also conclude that learning to operate the COBAS CORE system is simple, as is management of the system through the user-friendly software.

A novel human phosphoglucomutase (PGM5) maps to the centromeric region of chromosome 9

The phosphoglucomutases (PGM1-3) in humans are encoded by three genes, PGM1, PGM2, and PGM3. These enzymes are central to carbohydrate metabolism. All three isozymes show genetic variation, and PGM1 has achieved prominence as a key marker in genetic linkage mapping and in forensic science. The human PGM genes are assumed to have arisen by gene duplication since their products are broadly similar in structure and function; however, direct proof of their evolutionary relationship is not available because only PGM1 has been cloned. During a search for other members of the PGM family, a novel sequence with homology to PGM1 was identified. Mapping using fluorescence in situ hybridization and somatic cell hybrids locates this gene to the centromeric region of chromosome 9. RT-PCR and Northern analysis indicate that this is an expressed PGM gene with widespread distribution in adult and fetal tissues. We propose that this gene be designated PGM5 and that it represents a novel member of the PGM family.

Correlation of loss of heterozygosity with cytogenetic analysis using G-banding and fluorescence in situ hybridization in aneuploid cultures from two human testicular germ-cell tumors

A detailed karyotype analysis using fluorescence in situ hybridization (FISH), with 24 chromosome-specific paint probes has been carried out on newly established cell lines from two testicular tumors, an i(12p)-positive teratoma, and an i(12p)-negative combined seminoma/teratoma. This has been correlated with loss of heterozygosity (LOH) and allelic imbalance, using DNA RFLP analysis to clarify the genetic changes and to identify any common regions of deletion or rearrangement. With G-banding alone, a total of 11 breakpoints were recognized. After FISH, the position of seven required revision, and 21 new ones were identified. The chromosomes involved most frequently in both tumors were numbers 1, 12, and 18. Breakpoints in 11q and 16q were also seen in both, and seven or more copies of 12p per cell were found in all clones. LOH was found for 18q in both tumors, and overall was much more frequent in underrepresented regions (one or two copies). On the whole, there was good agreement between the cytogenetic and DNA RFLP data; loci showing allelic imbalance generally had an odd number of copies of the chromosome region in which they were known to be located. Combined data on the chromosome 1 translocations in both tumors suggested that rearrangements were more complicated than cytogenetics alone had predicted.

Cardiovascular effects of the novel dual inhibitor of neutral endopeptidase and angiotensin-converting enzyme BMS-182657 in experimental hypertension and heart failure

Combined neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE) inhibition produces greater acute hemodynamic effects than either treatment alone. We investigated whether BMS-182657 (BMS), which bears inhibitory activities against both NEP and ACE, elicited similar enhanced effects. BMS inhibited NEP and ACE, in vitro (IC50 = 6 and 12 nM, respectively) and the pressor response to Ang I in rats. In deoxycorticosterone acetate (DOCA)-salt hypertensive rats sensitive to NEP inhibition but not to ACE inhibition, BMS at 100 mumol/kg i.v. lowered mean arterial pressure (MAP) from 180 +/- 6 to 151 +/- 5 mm Hg. In sodium-depleted, spontaneously hypertensive rats (SHR) sensitive to ACE inhibition but not to NEP inhibition, BMS at 100 mumol/kg p.o. lowered MAP from 151 +/- 4 to 123 +/- 5 mm Hg. Cardiomyopathic hamsters with heart failure were administered vehicle or one of the following (30 mumol/kg i.v.): the ACE inhibitor enalaprilat; the NEP inhibitor SQ-28603; or BMS. Enalaprilat and SQ-28603 had minimal hemodynamic effects. BMS decreased left ventricular end-diastolic pressure by 12 +/- 2 and 10 +/- 1 mm Hg and left ventricular systolic pressure by 27 +/- 2 and 23 +/- 3 mm Hg at 30 and 60 min, respectively (P < .05 vs. each other group). These changes were associated with a 40% increase in cardiac output, a 47% decrease in peripheral vascular resistance and a lowering of MAP by 21 +/- 3 mm Hg at 60 min (P < .05 vs. each other group). There were no significant differences in the changes in heart rate or left ventricular stroke work index among the four groups. Hence, BMS-182657 is a dual inhibitor of NEP and ACE, is antihypertensive irrespective of the activity of the renin-angiotensin system and has acute hemodynamic effects in hamsters with heart failure greater than those produced by selective inhibition of NEP or ACE. The NEP and ACE inhibitory activities of BMS-182657 act synergistically and mimic the interaction resulting from combining selective inhibitors of these enzymes.

The effects of anaemia on heart, placenta and body weight, and blood pressure in fetal and neonatal rats

1. Reports that maternal anaemia in pregnancy is associated with a greater placental: birth weight ratio, which predisposes towards high postnatal blood pressure in the human, led us to examine the effects of maternal anaemia during pregnancy on placental size, fetal and neonatal growth, and blood pressure development in the rat. 2. Nutritional anaemia was induced in female rats prior to mating and maintained throughout pregnancy and up until weaning of the pups. Fetuses were studied at 20 days of gestation (E20). Pups were studied on postnatal days 20 (P20) and 40 (P40), having been weaned onto normal rat chow at 21 days. 3. In the anaemic group placental: fetal body weight ratios were lower compared with controls. Body weights at all ages were lower in the anaemic group than in controls, despite a greater rate of growth in the anaemic group between P20 and P40. 4. At P20 heart weights of the anaemic group were almost twice that of controls, suggesting an alteration in their cardiovascular development. However, paradoxically, the systolic blood pressure of the anaemic group was lower than that of controls. 5. By P40 the systolic blood pressure of the anaemic group (136 +/- 3 mmHg) had increased and was greater than that in control pups (126 +/- 3 mmHg). 6. In conclusion, we have shown that there is a pronounced postnatal rise in systolic blood pressure associated with maternal anaemia during pregnancy, which is not related to a greater placental: birth weight ratio. Before weaning, anaemic pups have a lower systolic blood pressure than controls and there is an important association between the rate of postnatal growth and blood pressure.

Chemotherapeutic tumour targeting using clostridial spores

The toxicity associated with conventional cancer chemotherapy is primarily due to a lack of specificity for tumour cells. In contrast, intravenously injected clostridial spores exhibit a remarkable specificity for tumours. This is because, following their administration, clostridial spores become exclusively localised to, and germinate in, the hypoxic/necrotic tissue of tumours. This unique property could be exploited to deliver therapeutic agents to tumours. In particular, genetic engineering could be used to endow a suitable clostridial host with the capacity to produce an enzyme within the tumour which can metabolise a systemically introduced, non-toxic prodrug into a toxic metabolite. The feasibility of this strategy (clostridial-directed enzyme prodrug therapy, CDEPT) has been demonstrated by cloning the Escherichia coli B gene encoding nitroreductase (an enzyme which converts the prodrug CB1954 to a highly toxic bifunctional alkylating agent) into a clostridial expression vector and introducing the resultant plasmid into Clostridium beijerinckii (formerly C. acetobutylicum) NCIMB 8052. The gene was efficiently expressed, with recombinant nitroreductase representing 8% of the cell soluble protein. Following the intravenous injection of the recombinant spores into mice, tumour lysates have been shown, by Western blots, to contain the E. coli-derived enzyme.

Gene expression in response to retinoic acid in novel human chromosome 21 monochromosomal cell hybrids

To access a wide a variety of expressed sequence from human chromosome 21 we have placed this chromosome into undifferentiated P19 mouse embryonic carcinoma cells. Cell lines resulting from these experiments have a range of morphologies and a wide variety of karyotypes. We have studied the retinoic acid response of five cell lines, compared to P19 cells, by observing three markers of retinoic acid induced P19 differentiation--cell morphology, RAR alpha and Wnt1 transcription. We see an 'early' retinoic acid response effect, however this response breaks down by the time the 'late' gene. Wnt1 would be transcribed in P19 cells. A highly responsive cell line will be useful for cloning expressed sequences from human chromosome 21 which are produced by early genes in retinoic acid inducible pathways, such as those involved in neurogenesis.

Coexistence of subacute cutaneous lupus erythematosus and porphyria cutanea tarda: a case report

We report a case of coexisting cutaneous lupus erythematosus and porphyria cutanea tarda in an alcoholic outdoorsman. We discuss the therapeutic dilemmas encountered and eventual treatment approach: sunscreens, topical corticosteroids, alcohol abstinence, and phlebotomy.

Characterization of a mucin cDNA clone isolated from HT-29 mucus-secreting cells. The 3' end of MUC5AC?

HT-29 cells resistant to 10(-6) M methotrexate (HT29-MTX) secrete mucins with gastric immunoreactivity (Lesuffleur, T., Barbat, A., Dussaulx, E., and Zweibaum, A. (1990) Cancer Res. 50, 6334-6343). A 3310-base pair mucin cDNA clone (L31) was isolated from an HT29-MTX expression library using a polyclonal serum specific for normal gastric mucosa. It shows a high level of identity (98.6%) to clone NP3a isolated from a nasal polyp cDNA library (Meerzaman, D., Charles, P., Daskal, E., Polymeropoulos, M. H., Martin, B. M., and Rose, M. C. (1994) J. Biol. Chem. 269, 12932-12939). However, as a result of changes in reading frame, the 1042-amino acid deduced peptide contains four regions of a low similarity to the NP3a peptide. The amino acid sequence shows 36.3% similarity to part of the carboxyl-terminal sequence of MUC2 including the so-called D4 domain and 21.3% to the pro von Willebrand factor. A short amino acid sequence is similar to cysteine-rich sequences repeated in tracheobronchial, gastric, and colonic mucin cDNAs. The gene corresponding to L31 is located in the mucin gene cluster on chromosome 11p15.5. The patterns of mRNA expression were indistinguishable from those revealed with the JER58 probe (MUC5AC). Southern blot analysis indicates that the L31 and JER 58 sequences are within 20 kilobase pairs of each other. Together, these results suggest that L31 clone is the 3' end of MUC5AC.

A radiation hybrid panel for human chromosome 6q

A panel of 63 radiation-reduced hybrids has been derived from a mouse cell line containing a neo-marked human Chromosome (Chr) 6, primarily to provide a resource for higher resolution localization of new markers. Hybrids were generated with radiation doses of 40-400 Gy, selected in G418, and were shown by PCR to contain the neo gene. PCR was also used to score the retention of 15 loci that map from 6q13 to q25.2 of the current consensus map, plus six other loci assigned to 6q26-q27. An average retention frequency of 27.8% was observed, with the highest frequencies at D6S313 and D6S280 (63.5%) located near the centromere at 6q13, and at D6S283 (68.5%) at 6q16.3-q21, presumably close to the neo integration site. Lowest frequencies (4.8%) were observed for telomeric markers. All markers segregated independently except D6S297 and D6S193. Agreement and some improvement to the current consensus map of 6q was made by mapping 12 loci by the non-parametric statistical method of Falk. In addition, deletion mapping with informative hybrids allowed the ordering of six loci from 6q26 to q27 and permitted some integration of maps of this region.

Repression of angiotensin II and potentiation of bradykinin contribute to the synergistic effects of dual metalloprotease inhibition in heart failure

Neutral endopeptidase inhibition (NEP-I) and angiotensin converting enzyme inhibition (ACE-I) act synergistically to produce acute beneficial hemodynamic effects in models of heart failure. Blockade of the formation of angiotensin II (Ang II) acting together with potentiation of the natriuretic peptides, bradykinin and other vasoactive peptides may mediate the interaction of dual enzyme inhibition. In this study, the potential roles of Ang II repression and bradykinin potentiation were evaluated in conscious cardiomyopathic hamsters with compensated heart failure. The Ang II AT1 receptor antagonist, SR 47436 (BMS-186295), was administered at 30 mumol/kg, i.v. followed by i.v. infusion at 1 mumol/kg/min in combination with NEP-I (SQ-28603 at 30 mumol/kg i.v.). Cardiac preload (left ventricular end diastolic pressure) and afterload (left ventricular systolic pressure) decreased significantly more after the combination of Ang II blockade and NEP-I than after either treatment alone. This indicated that repression of Ang II contributes importantly to the NEP-I/ACE-I interaction. Bradykinin B2 receptor antagonism by Hoe 140 at 100 micrograms/kg, i.v. significantly blunted the decrease in left ventricular end diastolic pressure but not the decrease in left ventricular systolic pressure after dual NEP-I/ACE-I (SQ-28603 and enalaprilat each at 30 mumol/kg, i.v.). This suggests that bradykinin potentiation contributes to the preload-reducing, but not the afterload-reducing, acute effects of NEP-I/ACE-I. Hence, both Ang II repression and bradykinin potentiation are factors contributing to the synergistic hemodynamic effects of combined NEP-I and ACE-I in hamsters with heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional localization of DPP4 (alias CD26 and ADCP2) to chromosome 2q24

A panel of microcell hybrids containing fragments of chromosome 2 was analyzed for the presence of human DPP4, the gene that codes for dipeptidyl peptidase IV (or CD26), by specific PCR amplification of a fragment of the 3' untranslated region of the gene. This analysis placed DPP4 between LCT and GAD in bands q21 to q31. The localization was confirmed by in situ hybridization using two genomic probes that each revealed a hybridization signal in band q24. We also use the recent identification of the ADA binding protein as DPPIV to propose that the gene ADCP2 should be renamed DPP4.

Predicting oliguria following indomethacin for treatment of patent ductus arteriosus

Fifty-two consecutive infants who received intravenous indomethacin, 0.2 mg/kg, were reviewed to determine factors associated with the occurrence of oliguria. Serum creatinine and concentration prior to indomethacin did not predict the occurrence of oliguria. A mean urine output of less than 4.5 mL/kg/hr prior to the administration of indomethacin was the only factor that we determined to be associated with a significant risk of oliguria. Two infants developed symptomatic oliguria and both had a pre-indomethacin urine output less than 1.5 mL/kg/hr.

Vasectomy reversal--microsurgery for best results

OBJECTIVE

To determine whether microsurgery achieves a better result in vasectomy reversal than other macroscopic techniques.

PATIENTS AND METHODS

A series of 103 consecutive patients with a median age of 36 years (range 26-58) who underwent microsurgical vasovasostomy was studied. The method employed was a modification of a two-layer anastomotic technique. In the first 49 patients 8/0 Vicryl was used to create a two-layer anastomosis whereas in 54 patients 10/0 Ethilon was used.

RESULTS

Sperm were present in the ejaculate in 85% of patients who underwent bilateral vasovasostomy. The rate increased to 94% in those in whom 10/0 Ethilon had been used as the suture material but the difference was not statistically significant. In half of the patients sperm concentration, quality and motility improved over the 12 months following reversal. The fertility rate, measured between 8 months and 5 years after vasovasostomy, was 64% if the vasectomy had been performed within 10 years and fell to 39% if 10 years or more had elapsed. In the 10 patients who had undergone a failed reversal attempt elsewhere four had sperm in the ejaculate and two of these patients became fertile.

CONCLUSION

The additional time and effort required for a microsurgical approach to vasovasostomy were worthwhile to obtain patency and fertility rates which were superior to those of other techniques.

Identification of YAC and cosmid clones encompassing the ZFX-POLA region using irradiation hybrid cell lines

The human Xp21.3-p22.1 region is poorly mapped relative to other X chromosome regions. To target cosmid and YAC clones specifically from Xp21.3-p22.1 for rapid contig construction, a hybridization-based screening approach using irradiation hybrids has been used. Alu-PCR products generated from hybrid lines containing small overlapping fragments from Xp21-p22 were hybridized to an X chromosome cosmid library, and cosmids predicted by their hybridization pattern to map to the region of interest were analyzed by fluorescence in situ hybridization (FISH). Hybridization of the cosmids in pools to gridded YAC libraries identified 15 YACs, which were verified and tested for chimerism by FISH. Cosmid content analysis of the YACs defined two contigs, one with 12 YACs covering about 1.5 Mb and one with 3 YACs. Five YACs from the 12-YAC cluster had been previously recognized by DNA polymerase alpha (POLA). ZFX identified a single YAC; hence, the physical linkage of ZFX and POLA was demonstrated within the contig. Four YACs had been isolated previously with ZFX and these extend the contig to 2 Mb. Restriction mapping of several YACs demonstrates that ZFX and POLA are about 700 kb apart, a distance similar to that reported in the mouse between Zfx and Pola. The order of these two loci and two additional loci identified by homologous mouse linking clones was found to be conserved between human and mouse: tel-ZFX-DXCrc57-DXCrc140-POLA-cen. We have shown that YAC contigs can be rapidly constructed from targeted regions without the need for time-consuming YAC end rescue and chromosomal walking.(ABSTRACT TRUNCATED AT 250 WORDS)

Thromboxane and prostacyclin synthesis in experimental pancreas transplantation. Changes in parenchymal and vascular prostanoids

The principal causes of failure of a pancreas transplant are rejection and vascular thrombosis. There is an unusually high attrition rate for pancreas transplants, but study models have been difficult to develop. In a rat model that allows study of acute rejection to the exclusion of nonspecific effects of transplant surgery on the pancreas, in vitro synthesis of prostacyclin (PGI2) and thromboxane A2 (TXA2) by transplanted pancreas and the blood vessels transplanted with it was measured using an RIA for their stable hydrolysis products 6-keto-prostaglandin F1 alpha and thromboxane B2 (TXB2). TXB2 synthesis was significantly greater in allotransplanted pancreas than isotransplanted pancreas from the 5th day after transplantation. Rejection was complete in the allografted group 7-9 days after transplantation. 6-Keto-prostaglandin F1 alpha synthesis was similar in the pancreas for both allografts and isografts. Similar changes were seen in aorta, celiac artery, superior mesenteric artery, and portal vein transplanted with the pancreas. In the transplanted aorta, TXB2 was significantly greater in the allograft group from the third posttransplant day. A group of CsA-treated allografts sampled after 9 days had transplanted pancreatic parenchymal and vascular prostanoid synthesis in the isograft range. The changes in PGI2 and TXA2 synthesis that accompany cellular rejection may mediate vascular failure in rejecting pancreas transplants, and changes in PGI2 and TXA2 synthesis in blood vessels transplanted with the pancreas could promote early vascular thrombosis.

Combined inhibition of neutral endopeptidase and angiotensin converting enzyme in cardiomyopathic hamsters with compensated heart failure

Inhibition of the metallopeptidase neutral endopeptidase 3.4.24.11 (NEP) protects endogenous natriuretic peptides and potentiates their vasodepressor effects. Inhibition of angiotensin converting enzyme (ACE) attenuates the formation of angiotensin II and enhances the vasodepressor effect of endogenous kinins. A combination of NEP inhibition and ACE inhibition can potentially interact to shift the balance of vasoactive peptides toward vasodilation. This potential interaction was examined in conscious cardiomyopathic hamsters with low cardiac output and compensated heart failure. Neither the selective NEP inhibitor SQ 28,603 nor the selective ACE inhibitor enalaprilat (each at 30 mumol/kg, i.v.) caused significant changes in left ventricular end diastolic pressure or left ventricular systolic pressure when administered separately. However, the combination of these inhibitors, each at that dose, caused significant peak decreases in left ventricular end diastolic pressure and left ventricular systolic pressure of -12 +/- 1 and -18 +/- 4 mm Hg, respectively. In separate cardiomyopathic hamsters, this same combination of treatments resulted in significant decreases in mean arterial pressure (-13%) and total peripheral resistance (-37%) and an increase in cardiac output (36%) as compared with vehicle effects (P < .05). At 90 min after administration of SQ 28,603 alone, plasma atrial natriuretic peptide concentration was double that in the vehicle group. In the group receiving the combination of inhibitors, plasma atrial natriuretic peptide at 90 min was maintained at the high basal levels associated with this model despite the decrease in cardiac filling pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

A cosmid library specific for human chromosome regions 6p21.3 and 6q27

We have explored the potential of irradiation-fusion gene transfer (IFGT) hybrids as a source of well-defined human chromosome fragments from which probes can be derived. Extensive characterization of the IFGT hybrid 4J4 with a full panel of markers from Chromosome (Chr) 6 showed that the human DNA content derives largely from 6p21.3 and 6q27. A cosmid library has been constructed from 4J4 DNA, and 370 recombinants containing human DNA have been isolated and overlapping clones ordered into 20 contigs. Regional localization of representative clones from each contig, determined by fluorescent in situ hybridization (FISH), places 13 contigs in 6q27 and 6 in 6p21.3. Preliminary screening of cDNA libraries with selected cosmids has identified two expressed sequences. Since there are a number of medically important genes in both these regions of human Chr 6 with several disease loci linked to the HLA-A region in 6p21.3 and various tumor suppressor genes to 6q27, this library will provide a valuable resource to aid the isolation of candidate genes for these diseases. In addition, unique markers for detailed physical and genetic mapping of these regions of human Chr 6 can be easily obtained.

AICAR is not an endogenous mutagen in Escherichia coli

A number of observations in the Escherichia coli and Salmonella typhimurium literature could be explained by the hypothesis that a particular purine ribonucleotide precursor can be converted to the corresponding deoxyribonucleotide triphosphate, thereby becoming a base-analogue mutagen. The metabolite in question, AICAR (5-amino-4-carboxamide imidazole riboside 5'-phosphate), is also a by-product of histidine biosynthesis, and its (ribo)triphosphate derivative, ZTP, has been detected in E. coli. We constructed E. coli tester strains that had either a normal AICAR pool (pur+ his+ strains cultivated without purines or histidine) or no AICAR pool (purF hisG mutant strains, lacking the first enzyme of each pathway and cultivated in the presence of adenine and histidine). Using a set of lacZ mutations, each of which can revert to Lac+ only by a specific substitution mutation, we found that no base substitution event occurs at a higher frequency in the presence of an AICAR pool. We conclude that the normal AICAR pool in E. coli is not a significant source of spontaneous base substitution mutagenesis.

The pleiotropic effects of his overexpression in Salmonella typhimurium do not involve AICAR-induced mutagenesis

Inhibition of cell division associated with overexpression of hisH and hisF in Salmonella typhimurium is strongly reminiscent of a cellular response to DNA damage. On these grounds, we investigated the involvement of a metabolite which appeared to represent a possible candidate for an endogenous mutagen: the base analog 5-amino-4-carboxamide imidazole riboside 5'-phosphate (AICAR), a by-product of HisH and HisF activity. However, we showed that AICAR is not an endogenous mutagen in S. typhimurium. Other types of DNA damage induced by his overexpression seem also unlikely, since similar mutation rates are found in hisO+ and hisOc strains. We also show that AICAR production is not involved in the pleiotropic effects of his overexpression, since these are still observed in strains devoid of AICAR. Thus inhibition of cell division resulting from HisH and HisF overexpression must operate through a mechanism unrelated to the role of these proteins in histidine biosynthesis.

HNF4 and HNF1 as well as a panel of hepatic functions are extinguished and reexpressed in parallel in chromosomally reduced rat hepatoma-human fibroblast hybrids

Rat hepatoma-human fibroblast hybrids of two independent lineages containing only 8-11 human chromosomes show pleiotropic extinction of thirteen out of fifteen hepatic functions examined. Reexpression of the entire group of functions most often occurs in a block, and except for one discordant subclone, correlates with loss of human chromosome 2. The extinguished cells and their reexpressing derivatives have been examined for the expression of seven liver-enriched transcription factors. C/EBP, LAP, DBP, HNF3, and vHNF1 expression are not systematically extinguished in parallel with the hepatic functions. However, HNF1 and HNF4 show a perfect correlation with phenotype: these factors are expressed only in the cells showing pleiotropic reexpression. Since recent evidence indicates that HNF4 controls HNF1 expression, it can be proposed that the HNF4 gene is the primary target of the pleiotropic extinguisher.

Measurement of cardiovascular and renal function in unrestrained hamsters

We describe a preparation for measuring blood pressure, left ventricular end diastolic pressure, heart rate, and renal excretory variables (volume, electrolytes, glomerular filtration rate) in hamsters. The new approach offers an advantage over previously described methods by eliminating the problems associated with restraint. Hamsters were surgically implanted with venous and arterial catheters. A specially constructed bladder catheter, which allows flushing to minimize errors due to dead space and permits urine collection without restraining the animals, was also implanted. The hamsters were allowed to recover from surgery for 3 hours before being studied in a specially designed lucite housing unit. Representative results were obtained in cardiomyopathic and healthy hamsters.

Epidemiology of nematode infections of Soay sheep (Ovis aries L.) on St Kilda

The epidemiology of nematode infections of Soay sheep on the island of St Kilda over a period of 2 years (August 1988-August 1990) spanning a host population crash is described. Infective larvae (L3) levels on pasture were high (2422 +/- 365 L3/kg D.M. grass in midsummer 1988) when host population density was high, decreasing after the sheep population declined by 70% in early 1989 (601 +/- 14 L3/kg D.M. in midsummer 1989). The availability of infective larvae to sheep increased during the winter of 1988-1989, probably as a result of concentration of existing larvae on grass as vegetation was destroyed by bad weather and overgrazing. Increased availability of pre-parasitic stages was accompanied by a marked increased in faecal egg counts from sheep of all ages and both sexes. Prevalence and intensity of infection (faecal egg counts) were higher in males than females throughout the 2-year study (chi 2 = 208.3, P < 0.005 and F1, 2000 = 304, P < 0.001 respectively), except during the lambing periods, and decreased with age in both sexes. Changes in prevalence and intensity of strongyle infections were associated with changes in host population density. Prevalence and intensity of Dictyocaulus filaria larvae in faeces increased during the host population crash. Infection intensity decreased with age (F1, 203 = 44.02, P < 0.001) and was higher in males than females (F1, 203 = 13.45, P < 0.001).

Role of endothelin-1 and big endothelin-1 in modulating coronary vascular tone, contractile function and severity of ischemia in rat hearts

The effect of endothelin-1 (ET-1) and big ET-1 on coronary flow and contractile function was determined in isolated nonischemic and ischemic rat hearts. Both ET-1 (IC50 = 12 pMol) and big ET-1 (IC50 = 2 nMol) reduced coronary flow in a concentration-dependent manner, although ET-1 was > 100-fold more potent. Both compounds decreased contractility, an effect which was lost when coronary flow was held constant, indicating that ET-1 and big ET-1 decrease contractility secondary to reducing coronary flow. Mechanical reduction in coronary flow to levels equivalent to those seen for ET-1 or big ET-1 caused similar reductions in contractility. Both 30 pMol ET-1 and 10 nMol big ET-1 pretreatment significantly reduced the time to contracture in globally ischemic rat hearts, suggesting a proischemic effect. Phosphoramidon (100 microM, endothelin-converting enzyme inhibitor) and BQ-123 (0.3 microM, ETA receptor antagonist) abolished the preischemic increase in coronary perfusion pressure induced by big ET-1 as well as its proischemic effect, whereas only BQ-123 abolished the cardiac effect of ET-1. Neither phosphoramidon nor BQ-123 had an effect on severity of ischemia when given alone. Phosphoramidon was also given i.v. to rats subjected to coronary occlusion and reperfusion and was found to significantly reduce infarct size 24 hr postischemia. Thus, in isolated rat hearts, big ET-1 appears to be converted to ET-1 and is a potent coronary constrictor.(ABSTRACT TRUNCATED AT 250 WORDS)

Morphology of rejection in experimental pancreas transplantation and its modification by cyclosporin A administration

Histology of pancreas transplant rejection is complicated by non-specific appearances related to undrained exocrine secretions. Using a rat model of pancreas transplantation with exocrine drainage into the urinary tract, morphology of acute rejection has been studied with minimal interference from non-specific change. Unmodified acute rejection was complete after 7-9 days. Intralobular lymphocytic infiltration, which differentiated allografts from isografts, was present 5 days after transplantation and lymphocytic infiltration of islets and blood vessel walls developed between 5th and 7th days. Cyclosporin A immunosuppression of allografts resulted in marked attenuation of the cellular infiltrate. The nature of the infiltrate and its suppression with cyclosporin A indicated an allograft reaction.

Stage I seminoma of the testis: is post-orchidectomy surveillance a safe alternative to routine postoperative radiotherapy?

Experience with the management of 128 patients with Stage I testicular seminoma over a 10-year period, 1980-1989, is presented. Fifty-six patients were treated with post-orchidectomy radiation therapy and 72 patients were put on surveillance. Patients thought to be at higher risk of relapse were generally treated with radiotherapy. There have been no tumour related deaths in this series; 5.4% of the irradiated group and 18% of patients on surveillance have relapsed to date. All relapses have been salvaged with further therapy and are currently in complete remission. In this interim analysis, surveillance appears to be a safe alternative to adjuvant radiation therapy provided regular, prolonged follow-up can be ensured. Surveillance is, however, time consuming and resource demanding, and should be undertaken only as part of a formal clinical study. Adjuvant post-orchidectomy radiotherapy should be considered the treatment of choice until further long-term data are available.

Sleep-disordered breathing in elderly people and subjective sleep-wake disturbance

Sleep-disordered breathing and subjective reports of sleep-wake disturbances are both common in elderly people but previous studies investigating the relationship between the two have produced uncertain results. We hypothesized that there is no relationship between sleep-disordered breathing and subjective reports of sleep-wake disturbance. Ninety-three random-sampled retirement-village residents, mean age 77.6 years, were monitored overnight with a portable microprocessor-based system. The respiratory disturbance index (RDI) was used as a measure of sleep-disordered breathing. Subjects were interviewed regarding sleep-wake patterns and snoring history and the Mini Mental State Examination, Geriatric Depression Scale and Nelson Adult Reading Test were administered. The sleep-wake responses were entered into a principal components analysis. Two components, reflecting night-time and daytime disturbance, accounted for 34% of the variance. Multiple regression analyses were performed using RDI as a continuous dependent variable, and three predictor variables, night-time, and daytime disturbance and history of snoring. Together, these variables accounted for only 2% of the variance. We conclude there is no relationship between mild and moderate sleep-disordered breathing and subjective sleep-wake disturbance in this population.

Regional localization of a trophoblast antigen-related sequence and 16 other sequences to human chromosomes 6q using somatic cell hybrids

Using a panel of 13 hybrid cell lines, we have regionally localized 22 markers to the long arm of chromosome 6. Revised or new locations are provided for 17 of the markers, and preliminary assignments to chromosome 6 of 11 loci are confirmed. The location of NT5, previously determined by antigen expression in hybrids, has been confirmed at 6q14-q15 by using a cDNA probe. Other DNA probes include one new anonymous sequence, designated D6S130, that maps to 6q12 and 4 VNTR probes that map to the proterminal band, 6q27. Probe CRI-L1065 also maps to 6q21, CRI-994 maps to 6q21-qter, and CRI-L322 maps to 6q14-15, information that may assist the merging of physical and genetic maps.

Red cell filterability determined using the cell transit time analyzer (CTTA): effects of ATP depletion and changes in calcium concentration

Cell transit time analysis (CTTA) is a new filtrometric technique for assessing red blood cell deformability by measuring the conductivity change caused by passage of erythrocytes through a polycarbonate filter. Most reported studies to date using CTTA have focused on the transit time (TT), the duration of passage of an individual red cell through a micropore. Bulk flow rate has not been previously measured via CTTA. The use of new enzyme based cleaning solutions make it possible to reduce clogging in micropore filters. Therefore, valid measures of the number of red cell transits per unit time (counts/s: C/S) can now be obtained. We evaluated both parameters, TT and C/S, as indicators of red cell filterability. Our goal was to evaluate the effect of metabolic changes shown by alternative techniques to affect red cell deformability. The two best established factors are changes in intracellular [ATP] and [Ca2+]. ATP depletion produces a very small increase in TT but a very marked decrease in C/S. In contrast, the addition of low concentrations of calcium produces an increase in TT with minimal decrease in C/S. The effects of calcium appear to be complex. The substantial changes in intracellular calcium induced by the ionophore A23187 result in a curvilinear pattern of increase in transit times and reduction in counts per s. Lanthanum, which inhibits egress of intracellular calcium, causes an increase in TT with a drop in C/S. We conclude that CTTA demonstrates the same changes in red cell deformability measurable by alternative filtrometric techniques; however, CTTA furnishes two separate and independent parameters which may be used to evaluate red cell deformability.