1) cf/cf = those carrying the disrupted CF gene from both parents
2) cf/+ = those which only carried the disrupted CFTRgene from one parent
3) +/+ (or "wild") = those inheriting no disupted CFTR gene at all(50).

Autopsy studies of the +/+ mice revealed that they were identical to normal mice. Six cf/cf mice were taken from the three litters and killed for autopsy, whilst the remain
der were allowed to live beyond the study period - i.e. until they were 30 days old(50

The Edinburgh researchers examined the effect on the body system of cf/cf mice :

SAV note - the examination is purely anatomical, it only provides anatomical data. Physiological, pathophysiological, pathological, endocrinal, immunological, neurological, embryological and congenital data is therefore only open to 'research' hypotheses. Human CF is not an anatomical problem by its own merit, it is all of these by way of human bios. It does not provide evidential data at the cellular or molecular level, let alone the geneticlevel, since CF cells, molecules and genes when in bios are behaviourally alive not dead, the conclusions drawn are completely circumstantial.

Reproductive System
The reproductive organs of the cf/cf mice were quite normal, except for one cf/cf mouse which had an increase in a constituent (mucin) of mucus in the vas deferens (the ducts that conduct spermatazoa).  Although this effect was only seen in one mouse, the experimenters interpreted the finding to mean that it "mimics the pathology in cystic fibrosis, and that this mouse model may be valuable for studying male
infertility"(50).

Intestines
Some changes were noted in the colon of cf/cf mice, including mild dilation with abnormal mucus accumulation(50).

Pancreatic System
At the time of publication, of their first paper on their mouse "model", the Edinburgh team had found no evidence of pancreatic abnormalities, and went so far as to write, "the ductal blockage that typifies most [human] cystic fibrosis patterns might be expected to be less severe in mice, or to develop later"(50).

Respiratory System
The experimenters found that one of the cf/cf mice, which had survived for 30 days, showed mild collapse of the alveoli in a small part of its lung. The researchers believed this finding was consistent with pre-symptomatic lung diseases, and used this one instance in an attempt to address the differences in the lungs seen in CF mice and in human CF patients -writing, "Differences between the pulmonary anatomy of mouse and [hu]man[s] has called into question whether a mouse mutant for CFTR would mimic the human lung diseases. But the one cf/cf mutant mouse described...that exhibited clear signs of lung damage is significant and consistent with the age of onset of lung disease in human patients"(50).

The Edinburgh team (no doubt, confident that their mouse "model" had overcome some problems that others had experienced) compared their mouse with the North
Carolina mouse, and reported, "the two types of mouse mutant do however display interesting and significant differences in viability and pathology which merit comment. [North Carolina] mutants.. show frequent prenatal death with intestinal obstruction, but not lung or gonadal pathology. By contrast, our [Edinburgh]... mutants are viable and show mild intestinal obstruction in association with gut, lung and gonadal pathology, characteristic of cystic fibrosis"(50).

Publication of the findings by the Edinburgh team resulted in other journals expressing the view that a "model" for the lung condition (which kills 95% of human CF sufferers(51,52)) had been developed. `New Scientist`recorded, "Scottish researchers have bred mice with an altered gene which displays all the key features of cystic fibrosis, such as lung disease and digestive problems"(53).

But, the same article also commented, "Writing in`Nature` Jim Wilson and Francis Collins at the University of Michigan say that time wlll tell how reliable a model the Edinburgh mouse will be.  Different animals in the colony had different manifestations of the disease, which could shed light on the differences between humans with CF, but could also complicate studies of the therapies, they say"(53). Interestingly, Wilson and Collins had actually written in their article in `Nature` (cited by `New Scientist`), "The apparent differences in the first two mouse models of CF underscore the complexities of modelling human diseases in animals"(54).

In May 1993, the Cambridge group compared the North Carolina mice with the Edinburgh mice. The Cambridge team wrote, "[North Carolina] mice have the more severe phenotype and most die within 30 days after birth from intestinal blockages caused by
hyperaccumulation of mucus. In addition, the animals fail to thrive, suffer from meconium ileus, and show alterations of mucus and serous glands, and do not show a cyclic-AMP-stimulated chloride channel in epithelial cells. In contrast, the Edinburgh animals show no overt clinical disease, and develop only minor pathological changes in a sub-set of animals"(55).

Despite only one out of six Edinburgh cf/cf mice examined at 30 days, showing mild collapse of the alveoli of the small part of the lung(56), and the Cambridge group reporting that the Edinburgh mice showed "no overt clinical disease"(57), the Cystic Fibrosis Trust stated, in its newsletter, of Summer 1994, that the Edinburgh mouse "survives longer and shows the essential hallmarks of the disease including lung pathology"(58).

It is said, ".scientists like mice because they are physiologically and genetically similar to humans(59) but there are fundamental differences between mice and people, including lifespan and physiology(60). For example, CF research led to the development ofgenetically modified CF mice. However, one team admitted that CF mice do not develop the liver problems common in human CF patients"(61).

To give some idea of the importance of a single amino acid difference, it is a single amino acid difference that is responsible for the diseases sickle cell anemia and cystic fibrosis. Very small differences on the cellular level between species, even species as closely related as humans and nonhuman primates, make for huge differences in disease response and treatment(62).

Despite these supposed mouse "models", Tsui found that there were "species differences" right down to the chromosomes. Using one of the (unspecified) mouse "models", for the meconium ileus condition, Tsui mapped the gene responsible to chromosome 7 and 5 (in the mouse), but in humans, it appears to be on chromosome 19(63).

GENE THERAPY

Biotechnology
Plasmids (minute rings of DNA genetic material), which exist outside the nuclei of bacteria and are capable of independent replication, can be opened up and a new piece of DNA material can be inserted. The modified plasmid can then be placed back inside a bacteria and grown to produce multiple copies of the foreign DNA fragment(64).

In Vitro Work
A team (from the Imperial Cancer Research Fund laboratories at the Institute of Molecular Medicine, University of Oxford; the John Radcliffe Hospital, Oxford; the Department of Pharmacology at the University of Cambridge; the Wellcome/Cancer Research Campaign Institute of Cancer and Development Biology; and the Department of Genetics at the University of Cambridge(65)), in collaboration with three UK charities (Wellcome Trust; the Imperial Cancer Research Campaign; and the Cystic Fibrosis Trust(66)) started to investigate correction of ion transport defects(67).

The team first used human cervical cancer (HeLa) cell lines to confirm delivery of the plasmid. Then, using biotechniques, they sought statement of the CFTR gene, and looked to see if that had been delivered and was in the human HeLa cell line(67) - but these investigators did not use human cystic fibosis lung cells in their studies.

Independently, effective transmission of the CFTR gene also demonstrated, in vitro, by the Edinburgh team -although they did not publish their data(68).

Animal Experiments

In America, adenoviruses were used as a "vector" because they dispatched the genes in the nucleus, but outside of the chromosomes, and were less likely to disrupt protein production(69). This method was reported in `Science` in 1992, by American researchers, who had used adenoviruses to transfer human CFTR into the airways of cotton rats(70).                                                                                           continued
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With knowledge, from clinical use, that iposomes are non-toxic and non-immunogenic(71), the team from Oxford and Cambridge believed that iposome might be more advantageous than the viral vectors such as adenoviruses - as used by the American investigators(72).

In 1992, two teams, Yoshimura and colleagues(73) and Stribing and his team(74) had, independently, demonstrated that plasmids, containing foreign NA, could be delivered into tissue covering the surface of the airway of rodents, and will replicate in