Spontaneous and induced chromosome damage in lymphocytes of medullary thyroid carcinoma patients and their family members.

Detailed chromosome analysis failed to reveal any evidence for spontaneous chromosome instability in lymphocytes from patients with multiple endocrine neoplasia, type 2 (MEN-2), whereas, with one exception, lymphocytes from MEN-2 patients were significantly more sensitive to chromosome damage by bleomycin and, to a lesser extent, MNNG than those from controls. The exceptional case suggests possible genetic heterogeneity in MEN-2.

Chromosome analysis of parallel short-term cultures from four testicular germ-cell tumors.

Cytogenetic analysis has been carried out on 17 parallel short-term cultures from four malignant testicular teratomas of intermediate differentiation (MTI), two of them combined with seminomas. Clonal development was seen in three tumors, with most of the variation involving different rearrangements of chromosome 1. Two copies of the i(12p), characteristic of testicular germ-cell tumors, were present in the two tumors with yolk sac elements, a single i(12p) and a 12q- were found in an MTI that had metastasized, and a rearrangement of chromosome 12 containing centromeric chromatin from chromosome 18 was found instead of the i(12p) in a mixed tumor. A 13p+ marker containing Q-negative material was seen in two of the tumors, with a der(7)t(Y;7) in one. Chromosomes 1, 3, 6, 7, 8, 12, 17, and X were invariably overrepresented either as complete or partial trisomies, and chromosomes 4, 5, 13, and 18 were underrepresented in all four tumors, strengthening the idea that tumor suppressor genes on the latter four chromosomes, all of which show some loss of heterozygosity with DNA markers, may be important in tumor progression.

Loss of heterozygosity in hypotriploid cell cultures from testicular tumours.

We have established cell lines with a hypotriploid chromosome number from four testicular tumours. Each line had at least one Y chromosome and most of the informative centrosome and enzyme markers were heterozygous implying that the tumours originated from germ cells before the first meiotic division. The small metacentric marker chromosome (i12p), specific for testicular tumours, was present in all tumour cell lines and up to three copies were found in some lines. Rearrangements of chromosome 1 and 11 were each found in three out of four tumours. The rearrangements of chromosome 1 all resulted in duplication of 1q and deletion of short-arm material from the same chromosome giving loss of heterozygosity for enzyme markers on 1p. Loss of satellite material from chromosome 13 and the centromere region of chromosome 9 were found in single cases. This study shows that even where the chromosome number of tumour cells is near triploid, regions of the genome can be deleted. The chromosomes most frequently involved in rearrangements, 1, 11, and 12 all contain sites of ras oncogenes and it is suggested that loss of normal alleles could result in homozygosity for mutant oncogenes which may play a part in tumour progression.

The role of lysosomal sialidase and beta-galactosidase in processing the complex carbohydrate chains on lysosomal enzymes and possibly other glycoproteins.

Previous studies using the lectin RCA-I from Ricinus communis have indicated that several lysosomal enzymes in the fibroblasts of patients deficient in beta-galactosidase carry excess terminal galactose. Electrophoretic studies have shown that the same enzymes and the non-lysosomal adenosine deaminase also show excess terminal sialic acid in patients deficient in sialidase. In this paper we confirm, using Jack-bean beta-galactosidase, that the binding to RCA-I of the purified N-acetyl-beta-D-hexosaminidase from a patient with GM1 gangliosidosis depends on a terminal beta-linked galactose. We provide evidence, using bacterial sialidase and measuring the binding to RCA-I, for excess subterminal galactose on the enzymes of patients deficient in sialidase. We also show that adenosine deaminase from the fibroblasts of patients deficient in beta-galactosidase has increased binding to RCA-I. These observations suggest that in healthy individuals the carbohydrate structure of the precursors of lysosomal enzymes and possibly some other glycoproteins also includes extended carbohydrate side chains with terminal sialic acid and subterminal galactose, and that the mature enzyme extracted from tissues is the product of degradation.

The origin of ovarian teratomas.

Chromosome and enzyme markers have been studied in 21 benign ovarian teratomas from 14 patients. Markers heterozygous in the patient were completely homozygous in 52% of the teratomas and completely heterozygous in 19%. The remainder showed a mixture of the two, 10% having homozygous centromeres with some heterozygous enzyme markers and 19% having heterozygous centromeres and some homozygous enzyme markers. These results suggest that benign ovarian teratomas in the present series arise from germ cells in a number of different ways. Those with heterozygous centromeres probably arise by failure of meiosis I. Some tumours with homozygous centromeres must arise by failure of meiosis II, but because of the low level of heterozygous enzyme markers in this group a substantial number are thought to arise by duplication of a mature ovum to give an entirely homozygous genotype, genetically the female equivalent of the complete hydatidiform mole.

The gene for human alpha-lactalbumin is assigned to chromosome 12q13.

A cDNA clone complementary to the mRNA encoding human alpha-lactalbumin (ALA) has been used as a probe in the analysis of DNA from panels of rodent/human somatic cell hybrids. The presence of the ALA gene correlates with the presence of chromosome 12. In situ hybridization localizes the ALA gene to 12q13.

Assignment of the human nicotinic acetylcholine receptor genes: the alpha and delta subunit genes to chromosome 2 and the beta subunit gene to chromosome 17.

The chromosomal assignments of the genes coding for the alpha, beta and delta subunits of the human nicotinic acetylcholine receptor have been determined from a panel of somatic cell hybrids and by direct in situ hybridization. The results localize CHRNA to 2q24-2q32. CHRNB to 17p11-17p12, and CHRND to chromosome 2q33-2qter.

Regional localization of a human cytochrome P-450 (CYP1) to chromosome 19q13.1-13.3.

A phenobarbitone inducible cytochrome P-450 gene family (CYP1) has recently been localized to chromosome 19q13.1-qter. We have used a human liver cDNA probe in in situ hybridization experiments to metaphase chromosomes from two balanced translocation carriers, 46,XX,t(11;19) (q13;q13.1) and 46,XX,t(7;19) (q31.3;q13.3) to obtain a more precise localization. The results suggest a regional assignment for CYP1 to chromosome 19q13.1-13.3.

Chromosome assignment, biochemical and immunological studies on a human aldehyde dehydrogenase, ALDH3.

The biochemical properties of ALDH isozymes have been examined in human tissues and one set, designated ALDH3, has been studied in detail. These components occur at highest levels in lung and stomach, but were not expressed in fetal tissues, or in blood, hair roots and fibroblasts. The ALDH3 isozymes show optimal activity with benzaldehyde and can use either NAD or NADP as cofactor. Antiserum against a partially purified ALDH3, from stomach, selectively precipitates this isozyme from human tissues and selectively recognizes an homologous component in the rat. Human and rodent ALDH3 were not immunoprecipitated by anti-ALDH1 or anti-ALDH2 antisera. High levels of expression were found in human-rodent hybrids, constructed using rat hepatoma cells, and these hybrids were used to assign the human ALDH3 gene to chromosome 17.

Regional assignment of the gene coding for human sucrase-isomaltase (SI) to chromosome 3q25-26.

The gene coding for sucrase-isomaltase (SI) has recently been mapped to chromosome 3 using a cDNA probe to analyse DNA from somatic cell hybrids (Green et al. 1987). We have now used this same cDNA probe to obtain a regional localization of this gene. In situ hybridization to normal metaphase chromosomes and to chromosomes from individuals with balanced translocations suggests a regional assignment to chromosome 3q25-26.

Isolation of a human cytochrome P-450 reductase cDNA clone and localization of the corresponding gene to chromosome 7q11.2.

We have isolated and sequenced cDNA clones that code for rat and human NADPH-dependent cytochrome P-450 reductase. The cDNA coding for the human protein was used to analyse, by Southern blot hybridization, DNA isolated from a panel of 8 independent human-rodent somatic cell hybrids. The results indicate that cytochrome P-450 reductase is encoded by a single gene (POR) located on human chromosome 7(pter-q22). Analysis of human metaphase chromosomes by hybridization in situ confirmed the results and refined the localization to 7q11.2. Northern blot hybridization revealed that in human liver the expression of the gene varies by less than 3-fold between different individuals.

The assignment of the human gene coding for complement C5 to chromosome 9q22-9q33.

The presence or absence of the human gene for the fifth component of complement (C5) was analysed in 19 human-rodent hybrid cell lines by hybridization to a radiolabelled probe derived from a human C5 cDNA clone. The segregation of C5 in these hybrids suggested that the gene is localized on chromosome 9, in the region 9q21-9qter. In situ hybridization refined the assignment of C5 to chromosome 9q22-33.

Human myosin heavy chain genes assigned to chromosome 17 using a human cDNA clone as probe.

A cDNA clone complementary to the mRNA encoding human myosin heavy chain has been isolated from a human fetal skeletal muscle cDNA library. A 600 base pair fragment of the inserted human cDNA has been used as probe in the Southern analysis of DNA from panels of rat/human and mouse/human somatic cell hybrids. All the sequences detected by this probe have been mapped to chromosome 17 in the region 17pter----17p11. There was no evidence for MHC sequences on any other chromosome.

Regional localization of carbonic anhydrase genes CA1 and CA3 on human chromosome 8.

The human carbonic anhydrase isozymes represent a family of homologous proteins which are important in respiratory function, fluid secretion, and maintenance of cellular acid-base homeostasis. Using somatic cell genetic techniques we have mapped two of the CA genes (CA1 and CA3) to human chromosome 8. In situ hybridization data demonstrates that both CA1 and CA3 map to the same region (q13-q22) of chromosome 8.

A cytochrome P-450 gene family mapped to human chromosome 19.

We have recently isolated a cloned cDNA coding for a cytochrome P-450 of human liver microsomal membranes, which corresponds to a major phenobarbital-inducible cytochrome P-450 of rat liver. This human cytochrome P-450 is encoded by a member of a multigene family. DNA extracted from a panel of 12 independent human-rodent somatic cell hybrids was analysed by Southern blot hybridization with the cloned cDNA. The results indicate that all components of this cytochrome P-450 gene family are located on chromosome 19. Evidence from hybrids derived from an individual carrying a balanced translocation suggests a regional localization of 19p13.2----qter. Analysis of human metaphase chromosomes by in situ hybridization localizes this cytochrome P-450 gene family further to the long arm of chromosome 19 in the region q13.1----qter. We propose the designation P450PB for this locus.

The Australian Incident Monitoring Study in Intensive Care: AIMS-ICU. The development and evaluation of an incident reporting system in intensive care.

Intensive care units are complex, dynamic patient management environments. Incidents and accidents can be caused by human error, by problems inherent in complex systems, or by a combination of these. Study objectives were to develop and evaluate an incident reporting system. A report form was designed eliciting a description of the incident, contextual information and contributing factors. Staff group sessions using open-ended questions, observations in the workplace and a review of earlier narratives were used to develop the report form. Three intensive care units participated in a two-month evaluation study. Feedback questionnaires were used to assess staff attitudes and understanding, project design and organization. These demonstrated a positive attitude and good understanding by more than 90% participants. Errors in communication, technique, problem recognition and charting were the predisposing factors most commonly chosen in the 128 incidents reported. It was concluded that incident monitoring may be a suitable technique for improving patient safety in intensive care.

Irradiation hybrids for human chromosome 11: characterization and use for generating region-specific markers in 11q14-q23.

High-dose irradiation hybrids containing fragments of chromosome 11 have been generated, with a view to isolating new region-specific markers. Forty-seven lines were scored for 34 markers: average retention was 6%. Fourteen lines contain markers from 11q14 to 11q23. One of these, Jo12, has 11q markers extending from tyrosinase (q14-q21) to PBGD (q23.3) plus one marker (TYRL, p11.2) from 11p. In situ hybridization using Alu PCR products from Jo12 as probe confirmed that the human DNA is derived from two regions, one in proximal 11p and a second, larger region in 11q23. Plasmid libraries of Alu PCR products from this and three other hybrids have been made. Six of eight recombinants identified as having single-copy inserts were mapped back to the regions of 11q22-q23 detected in the originating hybrid; only one mapped to a region not originally detected, and one was of hamster origin. These six clones provide new markers in 11q22-q23 that can be used directly for polymorphism studies. This series of hybrids is therefore a valuable resource for the rapid generation of markers from specific, defined regions of chromosome 11.