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101.
The glyoxylate cycle, which is well characterized in higher plants and some microorganisms but not in vertebrates, is able
to bypass the citric acid cycle to achieve fat-to-carbohydrate interconversion. In this context, the hydrodynamic transfer
of two glyoxylate cycle enzymes, such as isocytrate lyase (ICL) and malate synthase (MS), could accomplish the shift of using
fat for the synthesis of glucose. Therefore, 20 mice weighing 23.37 ± 0.96 g were hydrodinamically gene transferred by administering
into the tail vein a bolus with ICL and MS. After 36 hours, body weight, plasma glucose, respiratory quotient and energy expenditure
were measured. The respiratory quotient was increased by gene transfer, which suggests that a higher carbohydrate/lipid ratio
is oxidized in such animals. This application could help, if adequate protocols are designed, to induce fat utilization for
glucose synthesis, which might be eventually useful to reduce body fat depots in situations of obesity and diabetes. 相似文献
102.
Although exposure of LLC-PK1 epithelial cell sheets to phorbol esters (TPA)
causes a near immediate and total decrease of transepithelial electrical
resistance (TER), continuation of exposure for 3 to 4 days results in a
tachyphylactic response as TER begins to return to control levels. Recovery
of TER is maximal by 5 to 6 days, but reaches only 70 to 80% of control
level. A reciprocal change in the transepithelial flux of D-mannitol
indicates that the TER decrease is indicative of an increase in tight
junction permeability. Exposure of cell sheets to TPA for several days also
results in the appearance of multilayered polyp- like foci (PLFs) across
the otherwise one cell layer thick cell sheets. The pattern of penetration
of the electron dense dye, ruthenium red, from the apical surface, across
the tight junction and into the lateral intercellular space indicates that
the tight junctions of the cell sheet become uniformly leaky after acute
exposure to TPA. However, when exposure is continued for several days, only
the junctions of cells in the PLFs manifest leakiness. The decrease in TER
following acute TPA exposure correlates with the translocation of protein
kinase C-alpha (PKC alpha) into a membrane-associated compartment. With
exposure of several days, only a trace of PKC alpha is visible by Western
immunoblot, and this is in the membrane-associated compartment.
Immunofluorescent microscopy indicates that the trace of PKC alpha seen in
the Western immunoblots is ascribable distinctly to cells of the PLFs.
Monolayer areas between PLFs show no discernible immunofluorescent signal.
The data therefore indicate that tight junction barrier function may be
restored in certain areas by the down regulation of PKC alpha from the
membrane-associated compartment. Failure to down regulate may result in the
paracellular leakiness and abnormal cell architecture of the PLFs. Possible
implications of this model for in vivo epithelial tumor promotion are
discussed.
相似文献
103.
Cytogenetic and molecular genetic analysis of tumorigenic human bronchial epithelial cells induced by radon alpha particles 总被引:4,自引:1,他引:4
To establish a cell culture model for lung carcinogenesis, independent
populations of the human papillomavirus 18-immortalized human bronchial
epithelial cell line BEP2D were treated with high linear energy transfer
radon-simulated alpha-particles, expanded and xenotransplanted into Nu/Nu
mice. Six independent cell lines were established from tumors that
developed from three separate radiation treatments as follows: treatment
(Tx) 1 (30 cGy--two doses), H2BT, Tx 2 (30 cGy-- single dose), R30T1L,
R30T2 and R30T3L, Tx 3 (30 cGy--single dose), H1ATN and H1ATBA1.
Cytogenetic analysis revealed common changes in all tumor lines: loss of
the Y chromosome (ch), one of three copies of ch8, one of three copies of
ch14, and one of two copies of ch4p16-pter and ch11p15-pter. Analysis of
polymerase chain reaction-amplified short tandem repeats of informative
loci confirmed the loss of chY in all lines and loss of heterozygosity
(LOH) at eight loci spanning the length of ch8 in all lines from Tx's 1 and
2. Our data support previous studies indicating the presence of tumor
suppressor genes on ch8. LOH also was confirmed on ch14 at locus D14S306 in
all cell lines from Tx 2 and in one of two lines from Tx 3. This region,
14q12-q13, may contain changes in one of the five known somatostatin
receptor genes (SSTR1). No LOH was detected at any of the informative loci
tested for on ch4 or ch11.
相似文献
104.
105.
JA BATCH 《Journal of paediatrics and child health》1996,32(4):278-280
Abstract: Evidence exists for a potential role for inhaled corticosteroids, particularly when used in high dose to cause growth impairment, delayed maturation and adrenal suppression in children and adolescents with asthma. The functional significance of biochemical adrenal suppression remains uncertain. Similarly, there is as yet insufficient evidence to determine whether inhaled corticosteroids may adversely affect bone mineral density in children and adolescents with asthma. 相似文献
106.
Objective : To review experience of CYP11β1 deficiency (previously known as 11β-hydroxylase) at the Royal Children's Hospital, Melbourne, Victoria.
Methodology : A retrospective case review was conducted from 1974 to 1995 with five cases identified.
Results : Age of presentation ranged from 1 day to 7 years. Presentation was with ambiguous genitatia at birth (two females), simple virilization (two males) and suspected early puberty in mid childhood (one female). Associated clinical features were hypertension (three cases) and tall stature with markedly advanced bone age (four cases). Biochemical abnormalities consistent with CYP11β1-deficiency were elevated urinary tetrahydro-11-deoxycortisol ( n = 5) and elevated serum 11-deoxycortisol ( n = 3). Additional abnormalities were elevated 17-hydroxyprogesterone ( n = 3), elevated androstenedione ( n = 4) and elevated dehydroepiandrosterone sulphate ( n = 4). The clinical features and investigations suggested CYP11β1-classical deficiency in four patients and CYP11β1-non-classical deficiency in one patient.
Conclusions : The five cases of CYP11β1-deficiency demonstrate a spectrum of clinical abnormalities, with diagnostic difficulties in two cases and delayed presentation in three cases. Prompt diagnosis of CYP11β1-deficiency is facilitated greatly by the availability of a gas chromatography-mass spectrometry instrument and is essential to avoid the long-term effects of hypertension and hyperandrogenism. 相似文献
Methodology : A retrospective case review was conducted from 1974 to 1995 with five cases identified.
Results : Age of presentation ranged from 1 day to 7 years. Presentation was with ambiguous genitatia at birth (two females), simple virilization (two males) and suspected early puberty in mid childhood (one female). Associated clinical features were hypertension (three cases) and tall stature with markedly advanced bone age (four cases). Biochemical abnormalities consistent with CYP11β1-deficiency were elevated urinary tetrahydro-11-deoxycortisol ( n = 5) and elevated serum 11-deoxycortisol ( n = 3). Additional abnormalities were elevated 17-hydroxyprogesterone ( n = 3), elevated androstenedione ( n = 4) and elevated dehydroepiandrosterone sulphate ( n = 4). The clinical features and investigations suggested CYP11β1-classical deficiency in four patients and CYP11β1-non-classical deficiency in one patient.
Conclusions : The five cases of CYP11β1-deficiency demonstrate a spectrum of clinical abnormalities, with diagnostic difficulties in two cases and delayed presentation in three cases. Prompt diagnosis of CYP11β1-deficiency is facilitated greatly by the availability of a gas chromatography-mass spectrometry instrument and is essential to avoid the long-term effects of hypertension and hyperandrogenism. 相似文献
107.
JA Batch HR Davies BA Evans IA Hughes MN Patterson 《Archives of disease in childhood》1993,68(4):453-457
The partial androgen insensitivity syndrome occurs in 46,XY subjects with phenotypes ranging from perineoscrotal hypospadias with cryptorchidism and micropenis (mild undervirilisation) to clitoromegaly and partial labial fusion (marked undervirilisation). Within an affected family, wide variation in the degree of genital ambiguity between individuals can be seen. Two cousins of a previously reported subject who had severe genital ambiguity and partial androgen insensitivity were investigated. Neither of the cousins had genital abnormalities as marked as the index case, who also had qualitatively abnormal androgen binding and two mutations of the androgen receptor gene. Despite marked phenotypic differences between the index case and his cousins, similar androgen binding and the same androgen receptor mutations were shown in the cousins. Furthermore, one of the androgen receptor gene mutations has been shown in the mother and sister of one of the boys indicating that they are carriers. Thus phenotypic variation in families affected by partial androgen insensitivity is dependent on factors other than abnormalities of the androgen receptor gene alone. Although carrier status in partial androgen insensitivity can be determined, the severity of genital abnormalities in an affected offspring cannot be reliably predicted. 相似文献
108.
Twenty nine patients, aged 5-16 years, were studied to evaluate whether biofeedback training is effective in treating children with chronic constipation and encopresis; the clinical outcome at six weeks and 12 months was also evaluated. Patients received on average five biofeedback training sessions. The existence of external anal contraction or decreased rectal sensation in 16 (55%) and eight (27%) of the children, respectively was identified on manometry. After biofeedback training, 26 (90%) of the patients learned to relax the external anal sphincter; 18 (63%) normalised rectal sensation. The training resulted in a significant increase in defecation frequency and a significant decrease in encopresis. At six weeks, 16 (55%) of the patients were clinically symptom free. At follow up after 12 months the results were sustained. Only three patients showed a relapse within six months, of whom two were successfully treated with one extra training session. Biofeedback training might be a useful therapeutical approach in children with chronic constipation and encopresis. 相似文献
109.
M Cole L Parker AW Craft S Bell G Dale AC McGill JA Seviour J Smith 《Archives of disease in childhood》1993,68(3):376-378
The relationship between homovanillic acid (HVA), vanillylmandelic acid (VMA), and creatinine in the urine of 6 month old babies has been studied and reference ranges in the form of centiles constructed for HVA and VMA against creatinine. Over 10,000 urine samples were collected from babies in four health districts in the north of England. HVA and VMA concentration, either independently or when divided by creatinine concentration, were dependent upon the absolute concentration of creatinine in the sample. After adjustment for creatinine significant differences in the mean concentration of HVA were found between sexes. No such differences were found for VMA. HVA and VMA were also found to be age dependent. Centiles were constructed using a procedure which makes no distributional assumptions about the data. The net effect of utilising these centiles was to increase the predictive value of a positive screening test from 20% to 40% without any increase in the false negative rate. 相似文献
110.
NA Bridges JA Christopher PC Hindmarsh CG Brook 《Archives of disease in childhood》1994,70(2):116-118
The aetiology of 197 girls and 16 boys presenting with sexual precocity was reviewed. Ninety one girls and four boys had central precocious puberty (M:F 23:1); a cause was identified in all the boys but in only six girls. All boys with precocious puberty need detailed investigation; in girls investigation should be based on clinical findings, particularly the consonance of puberty. 相似文献