Identification of hub genes correlated with diabetic retinopathy via bioinformatics methods.

OBJECTIVE: The aim of this study was to identify the hub genes and uncover the molecular mechanisms of diabetic retinopathy (DR). MATERIALS AND METHODS: We used the Gene Expression Omnibus (GEO) dataset GSE60436 in our study. After screening for differentially expressed genes (DEGs), we performed gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis. Subsequently, a protein-protein interaction (PPI) network was constructed using the Search Tool for Retrieval of Interacting Genes (STRING) database and visualized using the Cytoscape software. Finally, we identified 10 hub genes by cytoHubba plugin. RESULTS: A total of 592 DEGs were identified, including 203 up-regulated genes and 389 downregulated genes. The DEGs were mainly enriched in visual perception, photoreceptor outer segment membrane, retinal binding, and PI3K-Akt signaling pathway. By constructing a protein-protein interaction (PPI) network, 10 central genes were finally identified, including CNGA1, PDE6G, RHO, ABCA4, PDE6A, PDE6B, NRL, RPE65, GUCA1B and AIPL1. CONCLUSIONS: CNGA1, PDE6G, RHO, ABCA4, PDE6A, PDE6B, NRL, RPE65, GUCA1B, and AIPL1 may be potential biomarkers and therapeutic targets for DR.

[A case of atypical iris corneal endothelial syndrome].

Iridocorneal endothelial syndrome is a rare ophthalmic disease, most of which are unilateral and common in women. The rate of misdiagnosis and missed diagnosis is relatively high due to its various clinical manifestations. In this case, the patient presented uncontrollable high intraocular pressure, corneal edema leading to difficult observation of corneal endothelium morphology, and accompanied by a small amount of iris neovascularization. No clearly diagnosis was made before glaucoma surgery. Further examination was performed after corneal clearance, and the final diagnosis was iris corneal endothelial syndrome (Chandler syndrome).

[Establishment of human colon cancer transplantation tumor model in normal immune mice].

Objective: Establishment of a new model of human primary colon cancer transplantation tumor in normal immune mice and to provide a reliable experimental animal model for studying the pathogenesis of colon cancer under normal immunity. Methods: Human colon cancer cells come from colon cancer patients who underwent surgery in the Affiliated Hospital of Jining Medical College in 2017. The mice in the cell control group were inoculated with phosphate buffered solution (PBS) containing colon cancer cells, the microcarrier control group was inoculated with PBS containing microcarrier 6, and the cell-microcarrier complex group was inoculated with the PBS containing colon cancer cell-microcarrier complex. The cells of each group were inoculated under the skin of the right axilla of mice by subcutaneous injection, and the time, size, tumor formation rate and pathological changes under microscope were recorded. The transplanted tumor tissue was immunohistochemically stained with the EnVisiion two-step method, and the tumor formation rate of the transplanted tumor was judged according to the proportion of positive cells in the visual field. The polymerase chain reaction (PCR) method was used to detect the expression of human-specific Alu sequence in mice tumor tissue. Results: After inoculation with tumor cells, the mice in the cell control group and the microcarrier control group did not die and did not form tumors; the mice in the cell-microcarrier complex group had palpable subcutaneous tumors in the right axillary subcutaneously on the 5th to 7th days after inoculation, and tumor formation rate is 67% (10/15), and the tumor volume can reach about 500 mm(3) 2 to 3 weeks after vaccination. The immunohistochemistry results showed that CK20, CDX-2 and carcinoembryonic antigen were all positively expressed. The PCR results showed that the expression of human-specific Alu sequence can be detected in the transplanted tumor tissue of tumor-bearing mice. Conclusion: Human primary colon cancer cells used microcarrier 6 as a carrier to form tumors in normal immunized mice, and successfully established a new model of human colon cancer transplantation tumor in normal immune mice.

LncRNA FAS-AS1 inhibits the progression of non-small cell lung cancer through regulating miR-19a-5p.

OBJECTIVE: Non-small cell lung cancer (NSCLC) is one of the most common and deadly tumors in the world. LncRNA FAS-AS1 was abnormally expressed in various cancers, such as non-small cell lung cancer. However, the underlying mechanism of FAS-AS1 in NSCLC remains to be elucidated. MATERIALS AND METHODS: The levels of FAS-AS1 and miR-19a-5p were measured using qRT-PCR in NSCLC cells. MTT and cell colony formation assays were performed to detect cell proliferative capacity. Transwell assay was carried out to measure cell migration and invasion. The relationship between FAS-AS1 and miR-19a-5p was confirmed using Luciferase reporter assay. Xenograft tumor experiment was conducted to detect the tumor growth in vivo. RESULTS: FAS-AS1 was remarkably down-regulated in NSCLC cells. FAS-AS1 inhibited cell proliferation, migration, and invasion in NSCLC cells. Additionally, FAS-AS1 directly targeted miR-19a-5p and negatively regulated the expression of miR-19a-5p in NSCLC cells. Furthermore, FAS-AS1 overexpression restored the promotion of miR-19a-5p overexpression on proliferation, migration, and invasion of NSCLC cells. Additionally, suppression of FAS-AS1 abrogated the inhibitory effects of miR-19a-5p knockdown on the progression of NSCLC. FAS-AS1 suppressed the tumor growth in vivo. CONCLUSIONS: FAS-AS1 suppressed cell proliferation, migration, and invasion by sponging miR-19a-5p in NSCLC, indicating that FAS-AS1 might be a potential biomarker and therapeutic target for NSCLC.

Trends in drug-resistant tuberculosis after the implementation of the DOTS strategy in Shenzhen, China, 2000-2013.

SETTING: The DOTS strategy has been regarded as the most cost-effective way to stop the spread of tuberculosis (TB) since its launch by the World Health Organization. OBJECTIVE: To estimate the effects of DOTS by tracking long-term trends in multidrug-resistant TB (MDR-TB). DESIGN: A retrospective cohort study was conducted from 2000 to 2013 to analyse trends in resistance to anti-tuberculosis drugs and the effect of DOTS-based treatment in Shenzhen, China, using the χ2 test. RESULTS: An overall MDR-TB rate of 4.2% was observed between 2000 and 2013, with an annual reduction of 0.16%. From 2000 to 2013, trends in resistance to isoniazid (INH), rifampicin (RMP) and MDR-TB declined significantly in new TB patients (P < 0.01), but not in retreatment cases. Sputum smear conversion rates after 2 months of treatment decreased significantly, in particular after 2007, in new and retreatment cases. CONCLUSION: INH and RMP resistance and MDR-TB rates declined significantly, suggesting that DOTS-based programmes were successful in reducing drug resistance in new cases but not in retreatment cases. The decreasing sputum smear conversion rates may have been due to an increase in the number of migrants. These two findings suggest that TB is unlikely to be completely eliminated by 2050 in Shenzhen.

Development and evaluation of a secondary reference panel for BCR-ABL1 quantification on the International Scale.

Molecular monitoring of chronic myeloid leukemia patients using robust BCR-ABL1 tests standardized to the International Scale (IS) is key to proper disease management, especially when treatment cessation is considered. Most laboratories currently use a time-consuming sample exchange process with reference laboratories for IS calibration. A World Health Organization (WHO) BCR-ABL1 reference panel was developed (MR(1)-MR(4)), but access to the material is limited. In this study, we describe the development of the first cell-based secondary reference panel that is traceable to and faithfully replicates the WHO panel, with an additional MR(4.5) level. The secondary panel was calibrated to IS using digital PCR with ABL1, BCR and GUSB as reference genes and evaluated by 44 laboratories worldwide. Interestingly, we found that >40% of BCR-ABL1 assays showed signs of inadequate optimization such as poor linearity and suboptimal PCR efficiency. Nonetheless, when optimized sample inputs were used, >60% demonstrated satisfactory IS accuracy, precision and/or MR(4.5) sensitivity, and 58% obtained IS conversion factors from the secondary reference concordant with their current values. Correlation analysis indicated no significant alterations in %BCR-ABL1 results caused by different assay configurations. More assays achieved good precision and/or sensitivity than IS accuracy, indicating the need for better IS calibration mechanisms.

YM155 down-regulates survivin and XIAP, modulates autophagy and induces autophagy-dependent DNA damage in breast cancer cells.

BACKGROUND AND PURPOSE: The aim of this study was to determine the potency and molecular mechanism of action of YM155, a first-in-class survivin inhibitor that is currently under phase I/II clinical investigations, in various drug-resistant breast cancers including the oestrogen receptor positive (ER(+) ) tamoxifen-resistant breast cancer and the caspase-3-deficient breast cancer. EXPERIMENTAL APPROACH: The potency of YM155 in SK-BR-3, MDA-MB-231, MCF7 and its tamoxifen-resistant sublines, TamR6, TamR7, TamR8, TamC3 and TamC6, were determined by MTT assay. Western blot analysis, flow cytometric analysis, reverse transcription-PCR, fluorescent microscopy and comet assay were used to determine the molecular mechanism of action of YM155 in different breast cancer cell lines. KEY RESULTS: YM155 was equally potent towards the parental ER(+) /caspase-3-deficient MCF7 breast cancer cells and its tamoxifen-resistant sublines in vitro. The ER(-) /HER2(+) SK-BR-3 breast cancer cells and the triple-negative/caspase-3-expressing metastatic aggressive MDA-MB-231 breast cancer cells were also sensitive to YM155 with IC50 values in the low nanomolar range. Targeting survivin by YM155 modulated autophagy, induced autophagy-dependent caspase-7 activation and autophagy-dependent DNA damage in breast cancer cells. Interestingly, YM155 also induced XIAP degradation and the degradation of XIAP might play an important role in YM155-induced autophagy in breast cancer cells. CONCLUSIONS AND IMPLICATIONS: YM155 is a potent survivin inhibitor that has potential for the management of various breast cancer subtypes regardless of the expression of ER, HER2 and caspase-3. Importantly, this study provides new insights into YM155's molecular mechanism of action and therapeutic potential in the treatment of tamoxifen-resistant breast cancer.

Comparison of vertebral bone marrow fat assessed by 1H MRS and inphase and out-of-phase MRI among family members.

UNLABELLED: Inphase and out-of-phase magnetic resonance imaging is a robust and fast method which can provide similar vertebral bone marrow fat estimation as (1)H proton magnetic resonance spectroscopy, indicating that this technique is a potentially useful tool in both research and clinical practice. INTRODUCTION: The importance of evaluating bone marrow fat lies in the fact that osteoporosis and obesity, two disorders of body composition, are growing in prevalence. Bone fat mass can be reliably assessed using proton magnetic resonance spectroscopy ((1)H MRS), but this method is technically demanding and needs advanced post-processing unlike inphase and out-of-phase magnetic resonance imaging (MRI), which is a robust and fast method. METHODS: We compared vertebral bone marrow fat (BMF) content assessed by inphase and out-of-phase MRI and (1)H MRS using a 1.5-T MRI scanner in mothers (n = 34, aged 49.4 years), fathers (n = 31, aged 53.1 years) and their daughters (n = 40, aged 20.3 years) who participated in the CALEX family study. Signal intensity on the inphase and out-of-phase MRI was analyzed from the same location and size of the single-voxel (1)H MRS measurement. RESULTS: Positive correlations were found between (1)H MRS and inphase and out-of-phase MRI in the axial plane (r = 0.746, p < 0.001) and sagittal plane (r = 0.804, p < 0.001). The mean differences between (1)H MRS and inphase and out-of-phase MRI in the axial and sagittal planes were relatively small, at 4.13 and 2.67 %, and the agreement between techniques was 89.4 and 93.2 %, respectively. Girls had a significantly lower vertebral BMF than mothers and fathers with both methods (for all, p < 0.001). CONCLUSIONS: We conclude that inphase and out-of-phase MRI can provide similar vertebral BMF estimation as (1)H MRS, indicating that this technique is a potentially useful tool in both research and clinical practice.

Risk factors associated with tuberculosis infection among health care workers in Inner Mongolia, China.

SETTING: Health care workers (HCWs) are at increased risk for tuberculosis (TB) infection. In China, surveys examining TB infection among HCWs have not studied general health care facilities, compared tuberculin tests conducted using local protocols against an internationally accepted test or characterised risk factors. OBJECTIVE: To measure the prevalence of and risk factors for TB infection among HCWs in Inner Mongolia, China. DESIGN: Between April and August 2010, we administered QuantiFERON®-TB Gold In-Tube (QFT-GIT) tests, skin tests using Chinese tuberculin (TST) and surveys among HCWs at an infectious diseases hospital and a general medical hospital. We assessed whether demographic characteristics, personal exposure and work exposure were associated with QFT-GIT and TST positivity, and assessed agreement between test results. RESULTS: Of 999 HCWs, 683 (68%) were QFT-GIT-positive, which was associated with greater age, longer HCW career, TB disease in a co-worker and greater daily patient exposure using multivariable analysis. TST reactions ≥ 5 mm occurred in 69% of the HCWs; agreement between test results was low ( 0.22). CONCLUSIONS: The prevalence of TB infection among HCWs in Inner Mongolia is high; infection was associated with occupational exposure. Results from locally conducted TST are difficult to interpret. In China, TB infection control in health care facilities should be strengthened.

Lactation is associated with greater maternal bone size and bone strength later in life.

SUMMARY: The association between lactation and bone size and strength was studied in 145 women 16 to 20 years after their last parturition. Longer cumulative duration of lactation was associated with larger bone size and strength later in life. INTRODUCTION: Pregnancy and lactation have no permanent negative effect on maternal bone mineral density but may positively affect bone structure in the long term. We hypothesized that long lactation promotes periosteal bone apposition and hence increasing maternal bone strength. METHODS: Body composition, bone area, bone mineral content, and areal bone mineral density of whole body and left proximal femur were assessed using DXA, and cross-sectional area and volumetric bone mineral density of the left tibia shaft were measured by pQCT in 145 women (mean age 48 years, range 36-60 years) 16 to 20 years after their last parturition. Hip (HSI) and tibia strength indexes (TBSI) were calculated. Medical history and lifestyle factors including breastfeeding patterns and durations were collected via a self-administered questionnaire. Weight change during each pregnancy was collected from personal maternity tracking records. RESULTS: Sixteen to 20 years after the last parturition, women who had breastfed in total more than 33 months in their life, regardless of the number of children, had greater bone strength estimates of the hip (HSI = 1.92 vs. 1.61) and the tibia (TBSI = 5,507 vs. 4,705) owing to their greater bone size than mothers who had breastfed less than 12 months (p < 0.05 for all). The differences in bone strength estimates were independent of body height and weight, menopause status, use of hormone replacement therapy, and present leisure time physical activity level. CONCLUSION: Breastfeeding is beneficial to maternal bone strength in the long run.

Availability of second-line drugs and anti-tuberculosis drug susceptibility testing in China: a situational analysis.

OBJECTIVE: To assess the availability of second-line drugs (SLDs) and the use of drug susceptibility testing (DST) results for the treatment of tuberculosis (TB) in China. DESIGN: Cross-sectional survey in 4675 health care facilities, 1960 of which have a dedicated TB clinic, in 12 provinces in China. RESULTS: More than 70% of TB clinics at the provincial and prefecture levels had at least one SLD available compared to 41.8% of facilities at the county/district level. The proportion of facilities at provincial, prefecture and county levels with any fluoroquinolone was respectively 74.1%, 64.9% and 34.5%. Sputum culture was performed at 6.0% of TB clinics at the county level, 37.5% at the prefecture and 59.3% at the provincial levels, while DST was performed only at the prefecture (28.6%) and provincial (44.4%) levels. Only 18% of the facilities that used SLDs for the treatment of multidrug-resistant TB (MDR-TB) based treatment regimens on DST results. CONCLUSION: SLDs are widely available in China for the treatment of both TB and other infectious diseases. To prevent the development of Mycobacterium tuberculosis resistance to SLDs, the availability of SLDs should be limited and they should be used with caution in the treatment of MDR-TB.

Effects of a low-frequency sound wave therapy programme on functional capacity, blood circulation and bone metabolism in frail old men and women.

OBJECTIVE: To evaluate the effects of a low-frequency sound wave therapy programme on functional capacity, blood circulation and bone metabolism of the frail elderly. DESIGN: Single-blind, randomized, controlled trial. SETTING: Two senior service centres. SUBJECTS: Forty-nine volunteers (14 males and 35 females) aged 62-93 years with up to 12 diagnosed diseases were allocated in either the intervention group (n = 30) or control group (n = 19). INTERVENTION: The intervention group underwent sound wave therapy, 3-5 times a week for 30 minutes per session over a period of 6 months. The control group received no intervention. MAIN MEASUREMENTS: Blood pressure, functional capacity, mobility, bone density, biochemical markers, isometric muscle strength, balance, and skin surface temperature. RESULTS: Compared with the control group, the intervention group's mobility and the amount of self-reported kilometres walked per week increased by 3 km (P<0.05), while levels of cholesterol (4.97 (0.72) to 4.52 (0.65) mmol/L, P =0.019), low-density lipoprotein (2.82 (0.72) to 2.45 (0.61) mmol/L, P =0.022), bone markers of total osteocalcin (11.0 (6.5) to 10.3 (5.9) ng/mL, P =0.048)) and tartrate-resistant acid phosphatase isoform 5b (2.50 (1.0) to 2.41 (1.1) IU/L, P =0.021)) decreased. The average skin surface temperature was significantly higher during active sessions at the end of the intervention than in the beginning (P = 0.004). No change was found during placebo sessions. CONCLUSIONS: Low-frequency sound wave therapy may have the potential to promote well-being of frail elderly subjects via improved functional capacity, especially in subjects who are too frail to undertake exercise.

Increasing tuberculosis case detection through intensive referral and tracing in Hunan, China.

OBJECTIVE: To explore a feasible approach to increase case finding of tuberculosis (TB) through intensive referral and tracing of TB suspects and patients. METHODS: A quasi-experimental study was conducted in three Chinese cities. A strategic referral and tracing system was developed for the local situation in Hunan, China. Data from a 1-year monitoring of referral, tracing and diagnosis of TB suspects/cases were used to assess outcomes. RESULTS: Among 126 public general hospitals and clinics in 38 project counties, the 124 (98.4%) health facilities that participated referred an average of 10 TB suspects and cases to the TB dispensary every month. A total of 6364 suspects and 5759 cases were referred. Compared to the previous year, the number of TB suspects increased by 102.1%, from 25 719 to 51 967; the referral of TB suspects increased five-fold; 10 596 new smear-positive pulmonary tuberculosis (PTB) cases were identified; and the notification of new smear-positive PTB increased by 112.9%, from 27.1/100 000 before the project year to 57.7/100 000, a significantly higher percentage than that of non-project areas, which had a notification rate of 38.8/100 000. CONCLUSION: Intensive referral and tracing of TB suspects/patients is a feasible and effective method of increasing case finding. Strengthening administrative interventions and incentives is essential to achieve project objectives.

Squeeze maneuver: an easy way to manage radiological contrast-medium extravasation.

BACKGROUND: Contrast-medium extravasation injuries may be self-limited to catastrophic. Adequate prophylactic measures are enforced when risk factors for extravasation are present, and prompt treatment can avoid serious complications. PURPOSE: To describe the squeeze maneuver, an effective method for the treatment of symptomatic contrast-medium extravasation. MATERIAL AND METHODS: Over a 3-month period, eight patients with >50 ml contrast-medium extravasation resulting in vascular compromise of the fingers were managed with the squeeze maneuver as follows. The intravenous catheter used for contrast-medium injection was removed, and the skin around the insertion site was cleaned with povidone-iodine. An 18-gauge needle was then used to puncture five to eight openings near the catheter insertion site as deeply as possible. We then began squeezing from the periphery of the swelling toward the needle holes. As the contrast medium drained, it was swabbed away with iodine-soaked cotton swabs. RESULTS: In all eight patients, the maneuver was successful with immediate resolution of the vascular compromise. CONCLUSION: The squeeze maneuver provides an easy way to manage radiological contrast-medium extravasation and can be performed immediately in the CT suite.

Genetic and phylogenetic analysis of multi-continent human influenza A(H1N2) reassortant viruses isolated in 2001 through 2003.

Genetic analyses were performed on 228 influenza A(H1) viruses derived from clinical subjects participating in an experimental vaccine trial conducted in 20 countries on four continents between 2001 and 2003. HA1 phylogenetic analysis of these viruses showed multiple clades circulated around the world with regional prevalence patterns. Sixty-five of the A(H1) viruses were identified as A(H1N2), 40 of which were isolated from South Africa. The A(H1) sequences of these viruses cluster with published H1N2 viruses phylogenetically and share with them diagnostic signature V169A and A193T changes. The results also showed for the first time that H1N2 viruses were prominent in South Africa during the 2001-2002 influenza season, accounting for over 90% of the A(H1) cases in our study, and infecting both children (29/31) and the elderly (11/13). Phylogenetic analysis of the 65 H1N2 viruses we identified, in conjunction with the 56 recent H1N2 viruses currently available in the database, provided a comprehensive view of the circulation and evolution of distinct clades of H1N2 viruses in a temporal manner between early 2001 and mid-2003, shortly after the appearance of these recent reassortant viruses in or near year 2000.

Fasting stimulates tuberoinfundibular dopaminergic neuronal activity and inhibits prolactin secretion in oestrogen-primed ovariectomized rats: involvement of orexin A and neuropeptide Y.

Fasting up-regulates central orexigenic systems including orexin A and neuropeptide Y (NPY) and it also inhibits the secretion of prolactin. We hypothesized that fasting may act through orexin A and NPY to influence tuberoinfundibular dopaminergic (TIDA) neurones, the major regulator of prolactin secretion. The effects of orexin A and NPY on TIDA neuronal activity and prolactin secretion were determined in oestrogen-primed ovariectomized rats, and the effects of fasting and the involvement of orexin A and NPY were tested. Orexin A, NPY and its analogs were administered through preimplanted intracerebroventricular (i.c.v.) cannulae. TIDA neuronal activity was determined by measuring concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) or 3,4-dihydroxyphenylalanine in the median eminence. i.c.v. injection of NPY (10 microg) or orexin A (1 microg) concomitantly increased median eminence DOPAC and decreased serum prolactin concentrations. The effect of NPY was mimicked by a Y1 receptor agonist at lower doses (0.1 and 1 microg) and no additive effect was observed when orexin A and the Y1 agaonist were coadministered. Moreover, a Y1 receptor antagonist, BIBP, not only blocked the effect of Y1 agaonist, but also that of orexin A. Treatment with BIBP alone decreased median eminence DOPAC and increased serum prolactin concentrations, indicating that endogenous NPY may play a role. Moreover, fasting for 48 h significantly increased TIDA neuronal activity, both in the morning and afternoon, and the effect was reversed by treatment with either BIBP or an antibody against orexin A. The findings support our hypothesis that fasting stimulates TIDA neuronal activity and inhibits prolactin secretion through up-regulated central orexin A and NPY systems.

Infection control considerations during construction activities: land excavation and demolition.

Because current trends in hospital restructuring in North America, amalgamations and mergers, and the aging of health care facilities, the need to restructure physical buildings has become greater. Hospital construction carries with it risks to patients. One key concern is the risk of aspergillosis associated with hospital construction. Infection control practitioners must consider some key factors when addressing land excavation and building demolition, which differ in some ways from construction that occurs within a health care facility. The key factors to consider are project concept, risk assessment of patients, procedures and environment, air quality, routes of entry and egress, soil management, conducting inspections, contingency planning, housekeeping, and lines of cooperation and communication with various stakeholders. Considering these areas will help ensure that health care facility personnel and the workers have exercised diligence in patient care.

Alternative splicing determines the function of CYP4F3 by switching substrate specificity.

Diversity of cytochrome P450 function is determined by the expression of multiple genes, many of which have a high degree of identity. We report that the use of alternate exons, each coding for 48 amino acids, generates isoforms of human CYP4F3 that differ in substrate specificity, tissue distribution, and biological function. Both isoforms contain a total of 520 amino acids. CYP4F3A, which incorporates exon 4, inactivates LTB4 by omega-hydroxylation (Km = 0.68 microm) but has low activity for arachidonic acid (Km = 185 microm); it is the only CYP4F isoform expressed in myeloid cells in peripheral blood and bone marrow. CYP4F3B incorporates exon 3 and is selectively expressed in liver and kidney; it is also the predominant CYP4F isoform in trachea and tissues of the gastrointestinal tract. CYP4F3B has a 30-fold higher Km for LTB4 compared with CYP4F3A, but it utilizes arachidonic acid as a substrate for omega-hydroxylation (Km = 22 microm) and generates 20-HETE, an activator of protein kinase C and Ca2+/calmodulin-dependent kinase II. Homology modeling demonstrates that the alternative exon has a position in the molecule which could enable it to contribute to substrate interactions. The results establish that tissue-specific alternative splicing of pre-mRNA can be used as a mechanism for changing substrate specificity and increasing the functional diversity of cytochrome P450 genes.