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Biomedical subjects

I Wang

Publications and source records attributed to I Wang.

35 records · Page 2Linked to original sources
PubMed1996

Photodynamic therapy using intravenous delta-aminolaevulinic acid-induced protoporphyrin IX sensitisation in experimental hepatic tumours in rats.

The efficacy of photodynamic therapy (PDT) using delta-aminolaevulinic acid (ALA)-induced protoporphyrin IX (PpIX) sensitisation and laser light at 635 nm was investigated in the treatment of experimental hepatic tumours. The model of liver tumours was induced either by local inoculation or by administration of tumour cells through the portal vein in rats. ALA at a dose of 60 mg kg(-1) b.w. was intravenously administered 60 min before PDT. PpIX accumulation in tumour, normal liver and abdominal wall muscle was detected by means of laser-induced fluorescence (LIF). Laser Doppler imaging (LDI) was used to determine changes in the superficial blood flow in connection with PDT. Histopathological examinations were performed to evaluate the PDT effects on the tumour and the surrounding liver tissue, including pathological features in the microvascular system. The accumulation of PpIX, as monitored by LIF, showed high fluorescence intensities at about 635 nm in both the hepatic tumour tissue and normal liver and low values in the abdominal wall. LDI demonstrated that the blood flow in the treated tumour and its surrounding normal liver tissue decreased immediately after the PDT, indicating an effect on the vascular system. A large number of thrombi in the irradiated tumour were found microscopically 3 h after the PDT. The tumour growth rate showed a marked decrease when evaluated 3 and 6 days after the treatment. These results show that the ALA-PDT is effective in the inhibition of growth of experimental hepatic tumours.

Aminolevulinic Acid↗
PubMed1995

Prevalence and molecular analysis of two hot spots for ectopic recombination leading to XX maleness.

Two hot spots of ectopic Xp-Yp recombination have previously been shown to be at the origin of XX maleness (Weil et al., 1994, Nature Genet. 7:414-419). To get more insight into the molecular basis of the abnormal interchange, 25 Y(+) class 3 XX male patients were studied. The two hot spots were found to account for the aberrant exchange in more than 50% of the cases. In addition, there is a correlation between the prevalence of each hot spot and the degree of X-Y homology between the corresponding fragments. Sequencing of the X-Y junctions in six patients, who carried a breakpoint mapping in either of these two hot spot fragments, showed that their precise locations were different from one individual to the other. In particular, the results obtained here in four new patients exclude the possibility that the repeated elements, present in these X-Y homologous fragments, are responsible for the high incidence of X-Y interchanges observed. Moreover, the breakpoints of all 25 class 3 XX males were found to be arranged in the same order on the X and Y chromosomes. This suggests that most ectopic recombinations leading to class 3 XX maleness involve X-Y homologous sequences persisting from an ancestral larger block of homology on the short arms of both sex chromosomes.

Base Sequence↗
PubMed1995

High-density physical mapping of a 3-Mb region in Xp22.3 and refined localization of the gene for X-linked recessive chondrodysplasia punctata (CDPX1).

The study of patients with chromosomal rearrangements has led to the mapping of the gene responsible for X-linked recessive chondrodysplasia punctata (CDPX1; MIM 302950) to the distal part of the Xp22.3 region, between the loci PABX and DXS31. To refine this mapping, a yeast artificial chromosome (YAC) contig map spanning this region has been constructed. Together with the YAC contig of the pseudo-autosomal region that we previously established, this map covers the terminal 6 Mb of Xp, with an average density of 1 probe every 100 kb. Newly isolated probes that detect segmental X-Y homologies on Yp and Yq suggest multiple complex rearrangements of the ancestral pseudoautosomal region during evolution. Compilation of the data obtained from the study of individuals carrying various Xp22.3 deletions led us to conclude that the CDPX disease displays incomplete penetrance and, consequently, to refine the localization of CDPX1 to a 600-kb interval immediately adjacent to the pseudoautosomal boundary. This interval, in which 12 probes are ordered, provides the starting point for the isolation of CDPX1.

Base Sequence↗
PubMed1995

Intra-operative laser-induced photodynamic therapy in the treatment of experimental hepatic tumours.

OBJECTIVE: To examine the effect of photodynamic therapy (PDT) on experimental liver tumours in rats. DESIGN: An experimental liver tumour model was used. Each of a group of rats had two tumours simultaneously inoculated into its liver. The tumour located in the left hepatic lobe was used for PDT, and the other one, in the median lobe, as a control. The haem precursor delta-amino laevulinic acid (ALA), at a dose of 30 mg/kg body weight, was injected 60 min before laser irradiation. Rats in group I received ALA through a femoral vein. Those in group II received ALA through the portal vein. Group III had an injection of ALA solution through the portal vein plus hepatic inflow occlusion. Three and 6 days after the treatment, the rats were killed, and the tumours were measured, and ultrastructural changes were examined using scanning electron microscopy. SETTING: Lund University Medical Laser Centre, Lund, Sweden. RESULTS: The mean tumour volume of the treated tumours increased by factors of 1.9, 1.5 and 1.7 in groups I, II and III, respectively, compared with the pretreatment baseline value. However, the mean tumour volume in the control tumours increased by factors of 9.5, 4.3 and 4.8 in the respective groups. Under the light microscope, marked necrosis of the treated tumour and the surrounding liver tissue was observed. Scanning electron microscopy revealed heavy damage to the cells and vessels in the treated tumour. CONCLUSION: PDT with ALA is an effective treatment modality for rat liver tumours.

Aminolevulinic Acid↗
PubMed1994

Highly homologous loci on the X and Y chromosomes are hot-spots for ectopic recombinations leading to XX maleness.

In 80% of XX males, maleness is due to the presence of Y-specific DNA including the SRY gene and results from an abnormal terminal X-Y interchange during paternal meiosis. Here we address the molecular basis of this ectopic recombination through the analysis of the X-Y junction in two class 3 XX males. We show that each of the rearrangements has involved X-Y highly homologous loci on the sex-specific part of these chromosomes (98.7% and 96% sequence identity over 1.2 and 1.1 kb respectively). Moreover in five out of six other XX males, the X-Y junctions are located in the same rearranged restriction fragment as in either of these patients. These fragments thus define two hot-spots of ectopic recombination which together could account for about one third of XX males. Evolution of these loci in primates is discussed.

Animals↗
PubMed1994

Photodynamic therapy of non-melanoma malignant tumours of the skin using topical delta-amino levulinic acid sensitization and laser irradiation.

Eighty basal cell carcinomas (BCCs) in 21 patients, 10 lesions of Bowen's disease in three patients, and four lesions of cutaneous T-cell lymphoma in two patients, were treated with photodynamic laser therapy (PDT), using topical application of the haem precursor delta-amino levulinic acid (ALA). The diagnoses were confirmed histologically prior to treatment. Fifty-five of the BCCs were superficial lesions, and 25 were nodular. Of the 80 BCCs, 39 (49%) were located on the trunk, 36 (45%) on the head and neck region, four (15%) on the leg and one on the arm. The two principal locations of the 10 Bowen's disease lesions were the leg (50%) and the trunk (40%). The T-cell lymphoma lesions were located on the shoulder and on the arm. A water-in-oil based cream containing 20% ALA was applied to the lesions, with a margin of about 10-20 mm beyond the visible tumour border, 4-6 h before the laser procedure. During this period of time the highly fluorescent and photodynamically active substance protoporphyrin IX (Pp IX) is synthesized via the haem cycle. Laser-induced fluorescence (LIF) was used for real-time monitoring of the Pp IX distribution in the tumour and in the normal surrounding skin, before and after treatment in all patients. Before laser treatment the Pp IX distribution demonstrated by LIF showed a demarcation between tumour and normal skin of about 15:1 for BCC and Bowen's disease, and 5:1 for T-cell lymphomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1994

Laparoscopic surgery for infertility therapy.

This review provides an update on the role of operative laparoscopy in infertility treatment. The areas of discussion include laparoscopic surgery for proximal and distal tubal disease, polycystic ovarian syndrome, endometriosis, and assisted reproduction.

Endometriosis↗
PubMed1993

A 45,X male with an X;Y translocation: implications for the mapping of the genes responsible for Turner syndrome and X-linked chondrodysplasia punctata.

In a male patient with a 45,X karyotype, the terminal part of the Y chromosome short arm was translocated as a single block on to the X chromosome. This rearranged X chromosome was, in every regard, the same as that present in XX males resulting from an abnormal X-Y interchange. Correlations between the phenotype of this patient and the extent of the deletions on the X and Y chromosomes allowed us to map the genes responsible for most features of the Turner syndrome between DXS432 and Xqter on the X chromosome, and the homologous Y genes either on Yp in interval 4 or on Yq. The molecular analysis of this X-Y translocation allowed us also to reduce the interval for the X-linked recessive chondrodysplasia punctata gene to a 1.5 Mb interval between DXS432 and DXS31.

Adolescent↗
PubMed1989

Detection of a Thy-1 precursor in human T lymphoma cell lines.

In an attempt to gain insight into the biosynthesis and processing of human Thy-1, rabbit antisera (R alpha TP) were raised against a synthetic peptide (TP) of 13 amino acid residues of identical amino acid sequence to that of residues 110-122 of the putative Thy-1 precursor deduced from the cDNA sequencing. Immunoblotting assay showed that the IgG fraction of R alpha TP (R alpha TP-IgG) recognized the synthetic peptide without demonstrable cross-reactivity with isolated human brain Thy-1 and detergent-solubilized membrane proteins of human brain cells. Immunohistochemical studies showed that both R alpha TP-IgG and HB-2S-1 (a monoclonal antibody which reacts with both membrane-bound Thy-1 on viable cells and detergent-solubilized Thy-1) stained cells of two human T lymphoma cell lines (HUT-78 and HUT-102) but they did not stain cells of a human B lymphoma cell line (Raji). In contrast, in cell surface indirect immunofluorescence assay, HB-2S-1 reacted with HUT-78 and HUT-102 cells while R alpha TP-IgG did not. Taken together, these data indicate the existence of a precursor form of human Thy-1 which is processed prior to anchoring to the cell surface.

Antigens, Surface↗
PubMed1972

Lead poisoning in rural Scotland.

Nine people from four families living in rural parts of Scotland have been found to suffer from clinical or biochemical effects of lead poisoning. Five had symptoms and four had unequivocal evidence of excessive lead exposure. The source of lead has been traced to the domestic water supply which in all cases was grossly contaminated with lead acquired from lead plumbing systems, including lead storage tanks. Clinical improvement followed the replacement of lead piping in two families studied. Lead poisoning is a possible cause of chronic ill health in areas of plumbosolvent water.

Adult↗
PubMed1971

Scintigraphy and arteriography in the diagnosis of diseases of the liver.

Arteriograms and scans performed over a five-year period on 60 patients with suspect hepatic disease have been reviewed. The diagnosis was proved in every case by biopsy, autopsy or laparotomy. Scintigraphy correctly predicted the presence or absence of disease in 75% and arteriography in 75% of cases. Fifty-four of the patients had hepatic disease. In 81% of these the accurate diagnosis of diffuse or localized disease was made by one or both techniques. Arteriography is preferred for the detection of localized lesions, but diffuse processes are more readily demonstrated by scintigraphy.

Angiography↗
PubMedDate not supplied

Blood perfusion studies on basal cell carcinomas in conjunction with photodynamic therapy and cryotherapy employing laser-Doppler perfusion imaging.

Superficial blood perfusion was monitored using laser-Doppler perfusion imaging in connection with a phase III clinical trial comparing photodynamic therapy, utilizing topically applied delta-aminolevulinic acid, with cryotherapy of basal cell carcinomas. A total of 526 images were recorded before and immediately after the treatment and during the follow-up period. Before treatment, the lesions exhibited a blood perfusion 3+/-2 times that in normal tissue. Both treatment modalities induced an increased blood perfusion inside the lesions, which slowly approached normal values in conjunction with successful treatments. The blood perfusion in successfully treated lesions approached normal values 2 months after photodynamic therapy, and about 1 year after cryotherapy. The tissue perfusion in recurrent lesions did not decrease to normal values after the treatment, suggesting that the laser-Doppler perfusion imaging technique can be used to follow the healing process and discover possible persistent tumour growth.

Adult↗