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Biomedical subjects

S Wells

Publications and source records attributed to S Wells.

At least 19 recordsLinked to original sources
PubMed1996

Transduction of pluripotent human hematopoietic stem cells demonstrated by clonal analysis after engraftment in immune-deficient mice.

Gene transduction of pluripotent human hematopoietic stem cells (HSCs) is necessary for successful gene therapy of genetic disorders involving hematolymphoid cells. Evidence for transduction of pluripotent HSCs can be deduced from the demonstration of a retroviral vector integrated into the same cellular chromosomal DNA site in myeloid and lymphoid cells descended from a common HSC precursor. CD34+ progenitors from human bone marrow and mobilized peripheral blood were transduced by retroviral vectors and used for long-term engraftment in immune-deficient (beige/nude/XIS) mice. Human lymphoid and myeloid populations were recovered from the marrow of the mice after 7-11 months, and individual human granulocyte-macrophage and T-cell clones were isolated and expanded ex vivo. Inverse PCR from the retroviral long terminal repeat into the flanking genomic DNA was performed on each sorted cell population. The recovered cellular DNA segments that flanked proviral integrants were sequenced to confirm identity. Three mice were found (of 24 informative mice) to contain human lymphoid and myeloid populations with identical proviral integration sites, confirming that pluripotent human HSCs had been transduced.

Animals↗
PubMed1996

Reproductive activity in captive female cheetahs (Acinonyx jubatus) assessed by faecal steroids.

Faecal oestradiol and progestogen metabolite excretion was monitored in adult, female cheetahs (Acinonyx jubatus) (n = 26) for 1-24 months. Increased faecal oestradiol excretion was associated with mating or equine chorionic gonadotrophin (eCG) administration for artificial insemination, whereas increased progestogen metabolites were observed during natural and human chorionic gonadotrophin (hCG)-induced pregnant and nonpregnant luteal phases. On the basis of oestradiol excretory patterns, duration of the oestrous cycle (mean +/- SEM) was 13.6 +/- 1.2 days with high oestradiol concentrations lasting for 4.1 +/- 0.8 days. In non-gonadotrophin-treated cheetahs, 75% showed evidence of oestrous cyclicity; however, none evaluated for 1 year or longer were continuously cyclic. Rather, cyclicity was interrupted by periods of anoestrus, often exceeding several months in duration. These inactive ovarian periods were unrelated to season and were not synchronous among females. Mean duration of gestation (breeding to parturition) was 94.2 +/- 0.5 days, whereas duration of faecal progestogen metabolite excretion during the nonpregnant luteal phase was 51.2 +/- 3.5 days. On the basis of progestogen metabolite evaluations, spontaneous ovulation (non-mating induced) occurred only once in two females (2 of 184 oestrous cycles; 1.1%). Peak eCG-stimulated, preovulatory oestradiol concentrations were similar to those associated with natural oestrus, whereas progestogen metabolite profiles after hCG resembled those during pregnant and nonpregnant luteal phases after natural mating. In summary, results confirm that the cheetah is polyoestrus and ovulation is almost always induced. However, new evidence suggests that many females inexplicably experience periods of anoestrus unrelated to season, while 25% of the cheetahs examined expressed no ovarian activity during the study period.

Acinonyx↗
PubMed1996

Changing hospital practices to increase the duration of breastfeeding.

OBJECTIVE: To change the breastfeeding policy in a university teaching hospital in accord with the Ten Steps to Successful Breastfeeding of the United Nations Children's Fund and World Health Organization and to assess the impact of hospital practices on the duration of breastfeeding. METHODS: One hundred ninety-two and 392 postpartum women in a maternity ward were interviewed in 1990 and 1993, respectively, regarding how they were feeding their infants and feeding practices in the hospital. Between these two periods, the hospital infant-feeding policy was reviewed and revised in accord with the Ten Steps. Two hundred seventy of the mothers interviewed in 1993 were interviewed again when their infants were 4 months old regarding the duration of full and partial breastfeeding. RESULTS: By 1993, more newborns were put to the breast in the first hour of life (63.2% vs 24.8%); fewer breastfed infants were fed foods other than breast milk (27.9% vs 46.7%); and more mothers received breastfeeding guidance from hospital staff (81.9% vs 61.3%). The duration of breastfeeding in 1993 was longer for women who did not receive formula in the hospital, who were not given discharge packs containing formula and/or coupons, and who roomed-in more than 60% of the time. These associations persisted after controlling for confounding. CONCLUSION: Infant-feeding policies and practices are amenable to change, and policies such as the Baby-Friendly Hospital Initiative may contribute to an increase in the duration of breastfeeding.

Adult↗
PubMed1995

Matching blood donations to type-specific product needs: a recruitment technique.

The conversion of multiple whole blood donors to apheresis donors is a challenge since a rapidly expanding apheresis donor base could erode homologous collections. We addressed this concern with a plan to enhance apheresis recruitment as well as donations among homologous donors with types O and B blood. Focusing the donor's attention on blood type as it relates to type-specific product needs was the basis of our approach. A matrix was used to recruit the desired types for the desired procedures (whole blood, platelet/plasma apheresis). The matrix instructed donors of blood types O, A-, and B- to primarily give whole blood and to give apheresis as a secondary donation. Donors AB, A+, and B+ were primarily directed to apheresis donations, whole blood donation being secondary. A+ and O- donors only gave their secondary donation if they were at maximum donations with the primary donation. The collections by blood type in percentages for 12 months of 1992/93 for whole blood were O+ 38.9, 0- 7.3, A+ 29.5, A- 5.7, B+ 11.9, B- 2.1, AB+ 3.7, AB+ 0.7. For apheresis it was 0+ 36.2, O- 6.7, A+ 33.0, A- 6.6, B+ 10.4, B- 1.2, AB+ 4.9, AB+ 1.0. In 1992/93, A+ and B+ apheresis collections as compared to total apheresis collections increased by 4.9% and 13.7%, respectively. For O group apheresis donations, a decrease of 2.5% was shown and A+ whole blood donations decreased by 5.35%. During the same period of time, total apheresis collections increased by 3,058 units. We demonstrated that integration of apheresis recruitment with type-specific whole blood recruitment yielded significant increases of type-specific products.

Blood Component Removal↗
PubMed1995

Genetic analyses of tattered, an X-linked dominant, developmental mouse mutation.

Tattered (Td) is an X-linked dominant mouse mutation that causes prenatal lethality in affected males. To map the locus, we analyzed 199 normal male and affected female progeny from a backcross of Td and Mus castaneus. Pedigree analysis of these animals suggests a gene order of cen-DXWas70-(Td, DXMit26, Gata1, Tcfe3)-(Cybb, Otc)-tel, where Tcfe3 is a transcription factor homologous to a gene involved in the murine microphthalmia (mi) mutation [Hodgkinson et al. Cell 74, 395-404, 1993]. To evaluate Tcfe3 as a candidate for Td, heterozygous tattered females were crossed to xid males to obtain females in which > 95% of B cells expressed genes solely from the Td X Chromosome (Chr). Fluorescent activated cell sorting (FACS) analysis and Western blotting of isolated splenocytes from Td/xid double heterozygotes rule out Tcfe3 as a likely candidate for the Td mutation.

Animals↗
PubMed1995

Pseudoangiosarcomatous carcinoma of the genitourinary tract.

Two cases of pseudoangiosarcomatous carcinoma of the genitourinary tract, arising in the vulva in one and the bladder in the other, are presented. In case 1, an 84 year old woman, the vulvectomy specimen contained an irregular ulcerated tumour, infiltrating the left labia and extending into the clitoris. In case 2, a 59 year old woman, the excised bladder showed diffuse thickening of its wall by infiltrating haemorrhagic tumour. Both tumours showed focal keratinisation. This, in association with the presence of atypical squamous epithelium, immunohistochemistry and ultrastructural analysis, led to a diagnosis of pseudosarcomatous carcinoma in both cases. Pseudoangiosarcomatous carcinoma should be considered in the differential diagnosis of malignant angiomatoid tumours, particularly those that arise at sites, like the genitourinary tract, where angiosarcoma is rare.

Aged↗
PubMed1995

Audit of tumour histopathology reviewed by a regional oncology centre.

AIMS: To analyse the diagnostic differences in reporting tumour histopathology between a district general hospital and a regional oncology centre. METHODS: Tumour histopathology reports (n = 227) extracted from Bolton General Hospital files between 1988 and 1992 were compared with the corresponding Christie Hospital (oncology centre) reports, the same material having been seen at both hospitals. RESULTS: Diagnostic agreement existed in 77% of all cases. The incidence of major discrepancies was 8.37%. Of the diagnoses, 19 (36%) cases involved major discrepancies and 34 (64%) cases minor discrepancies. Most discrepancies occurred in the lymphoma group and involved subclassification of Hodgkin's and non-Hodgkin's lymphoma. Ki1 anaplastic large cell lymphoma and T cell rich B cell lymphoma were problematic diagnoses. The correct grading of follicle centre cell lymphomas using the Kiel classification was another problem area. In 19 cases certain aspects of immunohistochemistry produced discrepancies. In one case an incorrect diagnosis was made at the oncology centre and in another both centres gave an incorrect diagnosis. CONCLUSIONS: Areas of diagnostic difficulty mainly involve the subclassification of lymphomas. Review of tumour pathology by experts is recommended, at least in certain categories, to ensure correct diagnosis and uniformity in subclassification of tumours.

Cancer Care Facilities↗
PubMed1995

The presence of an autologous marrow stromal cell layer increases glucocerebrosidase gene transduction of long-term culture initiating cells (LTCICs) from the bone marrow of a patient with Gaucher disease.

Gaucher disease is a lysosomal storage disorder resulting form deficiency of the acid beta-glucosidase, glucocerebrosidase (GC). Allogeneic bone marrow transplantation has been beneficial in the treatment of Gaucher patients. Therefore, this disorder may be an ideal candidate for gene therapy by GC gene transduction of hematopoietic stem cells. We sought to increase the extent of gene transfer into CD34+ cells from the marrow of a Gaucher patient using G1GC, a simple retroviral vector containing a normal human GC cDNA. The ability of autologous stromal support and recombinant cytokines to increase the extent of transduction of colony-forming-cells (CFCs) and long-term culture initiating cells (LTCICs) was assessed. The presence of a stromal layer significantly increased the extent of GC gene transfer into 14-day CFCs, as determined by polymerase chain reaction (PCR) of individual colonies (18.8% with stroma versus 5% without, P < 0.001). Stromal support also increased the extent of transduction of LTCICs (10% with stroma versus 0.83% without, P < 0.001). Non-adherent cells from long-term bone marrow cultures initiated with CD34+ progenitors transduced on autologous stroma had higher levels of GC enzyme activity than cultures initiated with cells transduced without stroma. The percentage of cells which were GC positive by immunohistochemistry was also increased (21.1% with stroma versus 2.7% without, P = 0.0003). The addition of cytokines (IL-3, IL-6 and Steel factor) to the transduction, in the presence of stroma, significantly increased the extent of gene transfer into CFCs but not LTCICs. These studies indicate that the GC gene can be effectively transduced into LTCICs by retroviral vectors in the presence of stroma at levels significant for clinical gene therapy trials in patients with Gaucher disease.

Antigens, CD↗
PubMed1994

Immunohistochemical studies on specificity and affinity of the BB5-antibody against human parathyroid tissue.

Localisation of parathyroid tissue in hyperparathyroidism may be difficult with standard methods. Immunoscintigraphy, using radiolabeled antibodies against epitopes of human parathyroid cells, could be a promising alternative. Therefore, we studied the necessary preconditions, whether the so-called BB5-antibody, directed against parathyroid cell membranes possesses sufficient specificity and affinity to be employed in immunoscintigraphy. Specificity was tested immunohistochemically with APAAP-staining of 39 different human tissues. Additionally, an immunoscore-based quantitative comparison was performed to test the affinity of BB5-antibody for normal and pathologic parathyroid tissue. Specificity was proven by the fact that of all 39 tested tissue-types only the parathyroid tissue was BB5-positive. Normal parathyroid tissue showed a significantly higher affinity to the BB5-antibody than pathologic parathyroid tissue (p < 0.03). However, all tissue samples from primary or secondary hyperparathyroidism exhibited sufficient staining. We conclude that the BB5-antibody fulfills the necessary conditions to be tried for immunoscintigraphical localisation of the parathyroid glands.

Adult↗
PubMed1994

Systemic argyria.

A 74 year old man presented with signs and symptoms of mild cardiac failure. His face and chest were severely discoloured, which was thought to be due to cyanosis. He deteriorated and died of bronchopneumonia. At post mortem examination multiple organs, including the skin, showed silver pigment deposition; he also had a gastric malignant neuroendocrine tumour. He gave no history of contact with silver compounds. Systemic argyria caused by chronic ingestion of silver compounds is a rare condition which, apart from its cosmetic effects, is thought to be relatively harmless; it is not thought to be carcinogenic. This condition can pose diagnostic problems for both clinicians and pathologists.

Adenoma↗