- Email: [email protected]
DESCRIBING BANDED CHROMOSOMES
358
gate complaints that in his opinion relate to the exercise of clinical judgment by doctors and other staff. The c.H.c. might therefore have a role in assisting individual complainants to use the complaints procedure and might provide a " patient’s friend " where one is needed. More commonly the c.H.c. would express local views on the nature and extent of the services provided and on planning matters. A council might well ask, for example, where people are to take their minor injuries and ills when the hospital casualty department becomes an accident and emergency unit and does not want to know about them, and when the G.P.S of the district are not exactly encouraging to any patient who has not made an appointment three days in advance and is not actually dying. Or it might decide to oppose the closure of further small hospitals in its district. DRAPER and SMART want to see the public involved in health-planning problems before the authorities become committed to any particular plan, and area health authorities will be " expected to consult the councils on plans for health service developments, and particularly on proposals for important variations in services affecting the public ".2 One would expect to see the community physician playing an important part in the dialogue between the area health authority and the c..c. on such matters as these, but again there is the danger that there will- be insufficient countervailing expert knowledge on the side of the consumer to enable an effective challenge to be mounted when decisions are taken on narrowly medico-technical grounds which can be made to appear compelling to most groups of laymen. The suggestion has been madethat an independent but publicly financed Health Service Consumer Council should be established to stimulate, guide, and advise the local councils and to provide them with the expert knowledge they are likely to lack. The weakness of this suggestion is that the council would probably have to be publicly financed; but it is difficult to see how else such a body could be supported. ...
DESCRIBING BANDED CHROMOSOMES
TECHNIQUES for banding chromosomes have opened new possibilities in human cytogenetics, but they have also posed problems. Laboratories have found it difficult to produce consistently good banding on a high proportion of mitoses, and poor or even moderately good chromosome preparations do not band well. The many techniques are not necessarily alternatives—they may be complementary, and full definition of a karyotype may require several of them.
up
Most laboratories have evolved their own variants which work under their own conditions. There has been urgent need for a system of describing the patterns produced by these various techniques. The
National Foundation-March of Dimes has 7. Hlth
soc.
Serv. J. Feb. 3, 1973.
just pub-
lished1 the report of the 1971 Paris conference on standardisation in human cytogenetics. The delay in publication, which has caused considerable frustration, can be forgiven now since the finished article is
concise, comprehensive, and designed uniformity well into the future.
to
preserve
The Paris recommendations are built on the nomenclature evolved in Denver in 1960 and modified and amplified in London (1963) and Chicago (1966).2 The nomenclature depends essentially on four techniques, each of which demonstrates a characteristic banding pattern. The basic description of each individual chromosome of the human karyotype is given in terms of bands seen using fluorescent dyes The bands, of the quinacrine type (Q bands).3 demonstrated by various pretreatments and then staining with a basic dye such as Giemsa, are termed G bands. G bands appear after incubation with citrate-saline solution4 and after treatment with
proteolytic enzymes5 or protein-denaturing agents.6 R bandswith one minor exception, are the reverse of the G bands, while C bands, which are taken to represent the constitutive heterochromatin, are largely confined to the centromeric regions.8 While these methods may stain a particular region in various different ways, they do define regions which are the same irrespective of the technique, and thus a system for numbering the bands is feasible. The proposed system recognises two cardinal difficulties in any such nomenclature-namely, that not all workers can achieve technical perfection, and that any system must be capable of expansion. The Paris system is essentially as follows. The short arms (p) and the long arms (q) are divided into bands that may be dark or light depending on the technique-there are no interbands. The centre points of certain striking features, such as a particularly deeply staining band, are taken as cytological landmarks which divide the chromosome arms in one to four regions. These regions should be and are numbered all workers easily recognised by outwards from the centromere. Thus 5q3 is the distal end of the long arm of chromosome 5. Within each region the bands now recognised are numbered again from proximal to distal, so that 5q34 is the fourth band from the centromeric end of region 5q3. Provision is made for further subdivision of these bands by adding further numbers after a decimal point, using the same conventions-a system which is comparatively simple yet capable of indefinite extension without resort to measurement, which is rightly
rejected. There
are two
versions of the nomenclature. The
shorter, which one hopes will be the more commonly used, is a relatively simple modification of the Denver system.
The chromosomes involved in
a
rearrange-
Conference on Standardisation in Human Cytogenetics (1971). Birth Def. orig. Art. Ser. 1972, vol. 7, no. 7. 2. Chicago Conference: Standardisation in Human Cytogenetics (1966). ibid. 1966, vol. 2, no. 2. 1. Paris
Caspersson, T., Lomakka, G., Zech, L. Hereditas, 1971, 67, 89. Sumner, A. T., Evans, H. J., Buckland, R. A. Nature New Biol. 1971, 232, 31. 5. Seabright, M. Chromosoma, 1972, 36, 204. 6. Lee, C. L. Y., Welch, J. P., Lee, S. H. S. Nature New Biol. 1973. 241, 142. 7. Dutrillaux, B., de Grouchy, J., Finaz, C., Lejeune, J. C. r. Acad Sci. Paris, 1971, 273, 587. 8. Arrighi, F. E., Hsu, T. C. Cytogenetics, 1971, 10, 81.
3. 4.
359
given in brackets after the number of chromosomes and the sex-chromosome complement. The break points are then indicated within a separate set of brackets and may be as precise or as vague as the ment are
.
.
demands.
Thus, 46,XY, rcp (2 ;5) male with 46 chromosomes and a (q21jq31) balanced reciprocal translocation between chromosome no. 2 and chromosome no. 5 with break points at band 1 in region 2 on the long arm of chromosome no. 2 and band 1 in region 3 on the long arm of chromosome no. 5. The longer version, which allows a detailed end-to-end description of the rearranged chromosomes, will be particularly useful in describing derived chromosomes in unbalanced karyotypes, but it is so long that it will probably only be used where special problems exist. Application of chromosome banding techniques has already led to advances in several different areas. Aberrations such as Down’s syndrome and the Philadelphia chromosome have been more precisely defined 9 and new abnormalities have been described, such as trisomy 8.10 But perhaps more interesting than the galaxy of new chromosome aberrations is the new insight which study of banding patterns gives on chromosome structure. If the staining of the Q, G, R, and C bands is looked at together with evidence from autoradiography, localisation of satellite 1).N.A.," and the Giemsa-11 technique 12 at least 8 different types of chromosome region can be defined. The two main types are (i) the majority of the light bands, and (ii) the majority of the dark bands. The exceptional regions are (iii) the centromeric regions, (iv) the secondary constriction regions of 1 and 6, (v) the secondary constriction region of 9, (vi) the whole of the inactive X, (vii) the distal region of the Y, and (viii) those regions observation
means a
.
; ; ,
,
°
°
°
w
.
’
the centromeres of 3, 4, 13, 14, 15, 21, and 22 which vary greatly in their fluorescence and may show polymorphism within the population (h regions).1 What this all means in terms of chromosome structure and the chemical composition of chromosomes is still obscure. While the denaturation and reannealing of
near :=
.
D.N.A. may
play
some
part,4 acridine-orange staining
indicates that much of the .
’
.
D.N.A. is not denatured by of the current pretreatments for G banding. 13 The effect of trypsin and of protein-denaturing agents6 suggests that the protein component is involved. In the meantime models based in microbial genetics should be extrapolated to mammalian cells only with the greatest of caution.
most
HYPERVISCOSITY SYNDROME IN MULTIPLE MYELOMA BLOOD viscosity is raised in three groups of disorders-those with increased numbers of blood-cells per unit volume; those with red cells that are less deformable than normal (due to changes in cell shape, 9. O’Riordan, M. L., Robinson, J. A., Buckton, K. E., Evans, H. J. Nature, 1971, 230, 167. 10. Caspersson, T., Lindsten, J., Zech, L., Buckton, K. E., Price, W. H. J. med. Genet. 1972, 9, 1. 11. Jones, K. W., Corneo, G. Nature New Biol. 1971, 233, 268. 12. Bobrow, M., Madan, K., Pearson, P. L. ibid. 1972, 238, 122. 13. de la Chapelle, A., Schroder, J., Selander, R. Hereditas, 1971,
69, 149.
size, and haemoglobin structure); and those with greatly increased concentrations of plasma-proteins.1 In both polycythaemia and sickle-cell disease, hyperviscosity contributes to the clinical picture by interfering with tissue perfusion, but the term hyperviscosity syndrome is reserved for cases of the third group in which plasma-proteins are raised and certain highly characteristic clinical features mucous
membranes
appear-bleeding from (notably, gums and nose) and
from
gastrointestinal tract; visual disturbances and a retinopathy consisting of venous engorgement, heemorrhages, exudates, and even frank papilloedema, and neurological disorders such as headache, vertigo, fits, hemiplegia, and coma. In addition, congestive cardiac failure and severe lethargy have been attributed to blood hyperviscosity. All these can be rapidly reversed by plasmapheresis.2 There is experimental evidence that the troubles are due to in-vivo red-cell agglutination, which does not happen to any great extent in polycythsemia even though blood viscosity, as measured in vitro, may be just as high.3 The hyperviscosity syndrome is a prominent feature of Waldenstr6m’s macroglobulinaemia but is rare in multiple myeloma. Its frequency in the macroglobulinæmia is attributed to the physical properties of the IgM molecule, which is large (M.w. about 1 million) and has a high axial-length/width ratio; the smaller, more compact IgG and IgA molecules (M.w. about 160,000) have less intrinsic Viscosity.2 Pruzanski and Watt4 have now provided the first well-documented information on the frequency of the hyperviscosity syndrome in IgG myeloma. Of a total of 238 patients with IgG myeloma seen over five years, 10 (4-2%) had one or more clinical features of hyperviscosity. All had other symptoms of myeloma before detection of the hyperviscosity state. These 10 patients were part of a subgroup of 46 with IgG paraprotein levels greater than 5 g. per 100 ml. Pruzanski and Watt reviewed a total of 61 casereports of the hyperviscosity syndrome in IgG myeloma published since 1965 and found that in sex and age, and in the relative distribution of kappa and lambda light chains, the group resembled other IgG-myeloma patients; the concentration of IgG, however, proved to be more than 5 g. per 100 ml. in 34 out of 37. There was no correlation between total protein or IgG level and measured serum viscosity. Although protein concentration is probably the most important factor determining blood viscosity in
myeloma, other properties of the paraprotein play a part. Subclass IgG3 gives serum hyperviscosity at lower concentrations than IgGl, probably owing to concentration and temperature dependent aggregation.4,5 Polymerisation of 7S IgG monomers into large complexes has been implicated in a number of 8 cases, 6,7 as has an abnormal shape of the IgG molecule.$ 1. 2.
3. 4. 5. 6. 7. 8.
Wells, R. New Engl. J. Med. 1970, 283, 183. Fahey, J. L., Barth, W. F., Solomon, A. J. Am. med. Ass. 1965, 192, 464. Rosenblum, W. J. Lab. clin. Med. 1969, 73, 359. Pruzanski, W., Watt, J. G. Ann. intern. Med. 1972, 77, 853. Capra, J. D., Kunkel, H. G. J. clin. Invest. 1970, 49, 610. Smith, E., Kochwa, S., Wasserman, L. R. Am. J. Med. 1965, 39, 35. Benninger, G. W., Kreps, S. I. ibid. 1971, 51, 287. Mackenzie, M. R., Fudenberg, H. H., O’Reilly, R. A. J. clin. Invest. 1970, 49, 15.
gate complaints that in his opinion relate to the exercise of clinical judgment by doctors and other staff. The c.H.c. might therefore have a role in assisting individual complainants to use the complaints procedure and might provide a " patient’s friend " where one is needed. More commonly the c.H.c. would express local views on the nature and extent of the services provided and on planning matters. A council might well ask, for example, where people are to take their minor injuries and ills when the hospital casualty department becomes an accident and emergency unit and does not want to know about them, and when the G.P.S of the district are not exactly encouraging to any patient who has not made an appointment three days in advance and is not actually dying. Or it might decide to oppose the closure of further small hospitals in its district. DRAPER and SMART want to see the public involved in health-planning problems before the authorities become committed to any particular plan, and area health authorities will be " expected to consult the councils on plans for health service developments, and particularly on proposals for important variations in services affecting the public ".2 One would expect to see the community physician playing an important part in the dialogue between the area health authority and the c..c. on such matters as these, but again there is the danger that there will- be insufficient countervailing expert knowledge on the side of the consumer to enable an effective challenge to be mounted when decisions are taken on narrowly medico-technical grounds which can be made to appear compelling to most groups of laymen. The suggestion has been madethat an independent but publicly financed Health Service Consumer Council should be established to stimulate, guide, and advise the local councils and to provide them with the expert knowledge they are likely to lack. The weakness of this suggestion is that the council would probably have to be publicly financed; but it is difficult to see how else such a body could be supported. ...
DESCRIBING BANDED CHROMOSOMES
TECHNIQUES for banding chromosomes have opened new possibilities in human cytogenetics, but they have also posed problems. Laboratories have found it difficult to produce consistently good banding on a high proportion of mitoses, and poor or even moderately good chromosome preparations do not band well. The many techniques are not necessarily alternatives—they may be complementary, and full definition of a karyotype may require several of them.
up
Most laboratories have evolved their own variants which work under their own conditions. There has been urgent need for a system of describing the patterns produced by these various techniques. The
National Foundation-March of Dimes has 7. Hlth
soc.
Serv. J. Feb. 3, 1973.
just pub-
lished1 the report of the 1971 Paris conference on standardisation in human cytogenetics. The delay in publication, which has caused considerable frustration, can be forgiven now since the finished article is
concise, comprehensive, and designed uniformity well into the future.
to
preserve
The Paris recommendations are built on the nomenclature evolved in Denver in 1960 and modified and amplified in London (1963) and Chicago (1966).2 The nomenclature depends essentially on four techniques, each of which demonstrates a characteristic banding pattern. The basic description of each individual chromosome of the human karyotype is given in terms of bands seen using fluorescent dyes The bands, of the quinacrine type (Q bands).3 demonstrated by various pretreatments and then staining with a basic dye such as Giemsa, are termed G bands. G bands appear after incubation with citrate-saline solution4 and after treatment with
proteolytic enzymes5 or protein-denaturing agents.6 R bandswith one minor exception, are the reverse of the G bands, while C bands, which are taken to represent the constitutive heterochromatin, are largely confined to the centromeric regions.8 While these methods may stain a particular region in various different ways, they do define regions which are the same irrespective of the technique, and thus a system for numbering the bands is feasible. The proposed system recognises two cardinal difficulties in any such nomenclature-namely, that not all workers can achieve technical perfection, and that any system must be capable of expansion. The Paris system is essentially as follows. The short arms (p) and the long arms (q) are divided into bands that may be dark or light depending on the technique-there are no interbands. The centre points of certain striking features, such as a particularly deeply staining band, are taken as cytological landmarks which divide the chromosome arms in one to four regions. These regions should be and are numbered all workers easily recognised by outwards from the centromere. Thus 5q3 is the distal end of the long arm of chromosome 5. Within each region the bands now recognised are numbered again from proximal to distal, so that 5q34 is the fourth band from the centromeric end of region 5q3. Provision is made for further subdivision of these bands by adding further numbers after a decimal point, using the same conventions-a system which is comparatively simple yet capable of indefinite extension without resort to measurement, which is rightly
rejected. There
are two
versions of the nomenclature. The
shorter, which one hopes will be the more commonly used, is a relatively simple modification of the Denver system.
The chromosomes involved in
a
rearrange-
Conference on Standardisation in Human Cytogenetics (1971). Birth Def. orig. Art. Ser. 1972, vol. 7, no. 7. 2. Chicago Conference: Standardisation in Human Cytogenetics (1966). ibid. 1966, vol. 2, no. 2. 1. Paris
Caspersson, T., Lomakka, G., Zech, L. Hereditas, 1971, 67, 89. Sumner, A. T., Evans, H. J., Buckland, R. A. Nature New Biol. 1971, 232, 31. 5. Seabright, M. Chromosoma, 1972, 36, 204. 6. Lee, C. L. Y., Welch, J. P., Lee, S. H. S. Nature New Biol. 1973. 241, 142. 7. Dutrillaux, B., de Grouchy, J., Finaz, C., Lejeune, J. C. r. Acad Sci. Paris, 1971, 273, 587. 8. Arrighi, F. E., Hsu, T. C. Cytogenetics, 1971, 10, 81.
3. 4.
359
given in brackets after the number of chromosomes and the sex-chromosome complement. The break points are then indicated within a separate set of brackets and may be as precise or as vague as the ment are
.
.
demands.
Thus, 46,XY, rcp (2 ;5) male with 46 chromosomes and a (q21jq31) balanced reciprocal translocation between chromosome no. 2 and chromosome no. 5 with break points at band 1 in region 2 on the long arm of chromosome no. 2 and band 1 in region 3 on the long arm of chromosome no. 5. The longer version, which allows a detailed end-to-end description of the rearranged chromosomes, will be particularly useful in describing derived chromosomes in unbalanced karyotypes, but it is so long that it will probably only be used where special problems exist. Application of chromosome banding techniques has already led to advances in several different areas. Aberrations such as Down’s syndrome and the Philadelphia chromosome have been more precisely defined 9 and new abnormalities have been described, such as trisomy 8.10 But perhaps more interesting than the galaxy of new chromosome aberrations is the new insight which study of banding patterns gives on chromosome structure. If the staining of the Q, G, R, and C bands is looked at together with evidence from autoradiography, localisation of satellite 1).N.A.," and the Giemsa-11 technique 12 at least 8 different types of chromosome region can be defined. The two main types are (i) the majority of the light bands, and (ii) the majority of the dark bands. The exceptional regions are (iii) the centromeric regions, (iv) the secondary constriction regions of 1 and 6, (v) the secondary constriction region of 9, (vi) the whole of the inactive X, (vii) the distal region of the Y, and (viii) those regions observation
means a
.
; ; ,
,
°
°
°
w
.
’
the centromeres of 3, 4, 13, 14, 15, 21, and 22 which vary greatly in their fluorescence and may show polymorphism within the population (h regions).1 What this all means in terms of chromosome structure and the chemical composition of chromosomes is still obscure. While the denaturation and reannealing of
near :=
.
D.N.A. may
play
some
part,4 acridine-orange staining
indicates that much of the .
’
.
D.N.A. is not denatured by of the current pretreatments for G banding. 13 The effect of trypsin and of protein-denaturing agents6 suggests that the protein component is involved. In the meantime models based in microbial genetics should be extrapolated to mammalian cells only with the greatest of caution.
most
HYPERVISCOSITY SYNDROME IN MULTIPLE MYELOMA BLOOD viscosity is raised in three groups of disorders-those with increased numbers of blood-cells per unit volume; those with red cells that are less deformable than normal (due to changes in cell shape, 9. O’Riordan, M. L., Robinson, J. A., Buckton, K. E., Evans, H. J. Nature, 1971, 230, 167. 10. Caspersson, T., Lindsten, J., Zech, L., Buckton, K. E., Price, W. H. J. med. Genet. 1972, 9, 1. 11. Jones, K. W., Corneo, G. Nature New Biol. 1971, 233, 268. 12. Bobrow, M., Madan, K., Pearson, P. L. ibid. 1972, 238, 122. 13. de la Chapelle, A., Schroder, J., Selander, R. Hereditas, 1971,
69, 149.
size, and haemoglobin structure); and those with greatly increased concentrations of plasma-proteins.1 In both polycythaemia and sickle-cell disease, hyperviscosity contributes to the clinical picture by interfering with tissue perfusion, but the term hyperviscosity syndrome is reserved for cases of the third group in which plasma-proteins are raised and certain highly characteristic clinical features mucous
membranes
appear-bleeding from (notably, gums and nose) and
from
gastrointestinal tract; visual disturbances and a retinopathy consisting of venous engorgement, heemorrhages, exudates, and even frank papilloedema, and neurological disorders such as headache, vertigo, fits, hemiplegia, and coma. In addition, congestive cardiac failure and severe lethargy have been attributed to blood hyperviscosity. All these can be rapidly reversed by plasmapheresis.2 There is experimental evidence that the troubles are due to in-vivo red-cell agglutination, which does not happen to any great extent in polycythsemia even though blood viscosity, as measured in vitro, may be just as high.3 The hyperviscosity syndrome is a prominent feature of Waldenstr6m’s macroglobulinaemia but is rare in multiple myeloma. Its frequency in the macroglobulinæmia is attributed to the physical properties of the IgM molecule, which is large (M.w. about 1 million) and has a high axial-length/width ratio; the smaller, more compact IgG and IgA molecules (M.w. about 160,000) have less intrinsic Viscosity.2 Pruzanski and Watt4 have now provided the first well-documented information on the frequency of the hyperviscosity syndrome in IgG myeloma. Of a total of 238 patients with IgG myeloma seen over five years, 10 (4-2%) had one or more clinical features of hyperviscosity. All had other symptoms of myeloma before detection of the hyperviscosity state. These 10 patients were part of a subgroup of 46 with IgG paraprotein levels greater than 5 g. per 100 ml. Pruzanski and Watt reviewed a total of 61 casereports of the hyperviscosity syndrome in IgG myeloma published since 1965 and found that in sex and age, and in the relative distribution of kappa and lambda light chains, the group resembled other IgG-myeloma patients; the concentration of IgG, however, proved to be more than 5 g. per 100 ml. in 34 out of 37. There was no correlation between total protein or IgG level and measured serum viscosity. Although protein concentration is probably the most important factor determining blood viscosity in
myeloma, other properties of the paraprotein play a part. Subclass IgG3 gives serum hyperviscosity at lower concentrations than IgGl, probably owing to concentration and temperature dependent aggregation.4,5 Polymerisation of 7S IgG monomers into large complexes has been implicated in a number of 8 cases, 6,7 as has an abnormal shape of the IgG molecule.$ 1. 2.
3. 4. 5. 6. 7. 8.
Wells, R. New Engl. J. Med. 1970, 283, 183. Fahey, J. L., Barth, W. F., Solomon, A. J. Am. med. Ass. 1965, 192, 464. Rosenblum, W. J. Lab. clin. Med. 1969, 73, 359. Pruzanski, W., Watt, J. G. Ann. intern. Med. 1972, 77, 853. Capra, J. D., Kunkel, H. G. J. clin. Invest. 1970, 49, 610. Smith, E., Kochwa, S., Wasserman, L. R. Am. J. Med. 1965, 39, 35. Benninger, G. W., Kreps, S. I. ibid. 1971, 51, 287. Mackenzie, M. R., Fudenberg, H. H., O’Reilly, R. A. J. clin. Invest. 1970, 49, 15.