Dexmedetomidine attenuates lipopolysaccharide-induced renal cell fibrotic phenotypic changes by inhibiting necroinflammation via activating α2-adrenoceptor: A combined randomised animal and in vitro study

BACKGROUND

Acute kidney injury (AKI) was reported to be one of the initiators of chronic kidney disease (CKD) development. Necroinflammation may contribute to the progression from AKI to CKD. Dexmedetomidine (Dex), a highly selective α2-adrenoreceptor (AR) agonist, has cytoprotective and "anti-" inflammation effects. This study was designed to investigate the anti-fibrotic properties of Dex in sepsis models.

METHODS

C57BL/6 mice were randomly treated with an i.p. injection of lipopolysaccharides (LPS) (10 mg/kg) alone, LPS with Dex (25 μg/kg), or LPS, Dex and Atipamezole (Atip, an α2-adrenoreceptor antagonist) (500 μg/kg) (n=5/group). Human proximal tubular epithelial cells (HK2) were also cultured and then exposed to LPS (1 μg/ml) alone, LPS and Dex (1 μM), transforming growth factor-beta 1 (TGF-β1) (5 ng/ml) alone, TGF-β1 and Dex, with or without Atip (100 μM) in culture media. Epithelial-mesenchymal transition (EMT), cell necrosis, necroptosis and pyroptosis, and c-Jun N-terminal kinase (JNK) phosphorylation were then determined.

RESULTS

Dex treatment significantly alleviated LPS-induced AKI, myofibroblast activation, NLRP3 inflammasome activation, and necroptosis in mice. Atip counteracted its protective effects. Dex attenuated LPS or TGF-β1 induced EMT and also prevented necrosis, necroptosis, and pyroptosis in response to LPS stimulation in the HK2 cells. The anti-EMT effects of Dex were associated with JNK phosphorylation.

CONCLUSIONS

Dex reduced EMT following LPS stimulation whilst simultaneously inhibiting pyroptosis and necroptosis via α2-AR activation in the renal tubular cells. The "anti-fibrotic" and cytoprotective properties and its clinical use of Dex need to be further studied.

Clinical pharmacology and pharmacogenomics for implementation of personalized medicine

With the aim of integrating clinical pharmacology with pharmacogenomics and providing a platform to gather clinicians, academicians, diagnostic laboratory personnel and scientists from related domains, the International Conference on Clinical Pharmacology and Pharmacogenomics 2023 (ICCPP 2023) was jointly organized by the Department of Pharmacology, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, India and the CANSEARCH research platform in Pediatric Oncology and Hematology, University of Geneva, Geneva, Switzerland. The conference was held on 31 August and 1 September 2023, as a continued Indo-Swiss scientific exchange event series. In this report we describe the proceedings of this conference for the benefit of peers who could not attend the conference but are interested in knowing about the scientific program in detail.

Liver injury associated with drug intake during pregnancy

Drug use during pregnancy is not common. Drug-induced liver injury (DILI) is a potential complication that is rare but can adversely affect both the mother and the fetus. Although many drugs can directly cause hepatotoxicity, idiosyncratic liver injury is common in pregnancy. Underreporting of adverse drug reactions, lack of adequate literature regarding drug safety in pregnancy, and the inherent difficulty in diagnosing DILI during pregnancy make the management of this condition challenging. This review attempts to describe the existing literature regarding DILI in pregnancy, which is mainly in the form of case reports; several studies have looked at the safety of antithyroid drugs, antiretroviral drugs, and paracetamol, which have an indication for use in pregnancy; the relevant data from these studies with regard to DILI has been presented. In addition, the review describes the diagnosis of DILI, grading the disease severity, assessment of causality linking the drug to the adverse event, regulatory guidelines for evaluating the potential of drugs to cause liver injury, efforts to ensure better participation of women in clinical trials and studies in pregnant women population in particular, and the challenges involved in generating adequate research evidence. The establishment of DILI registries in various countries is an encouraging development; however, there is a need for promoting active, spontaneous reporting of adverse events during pregnancy to ensure rapid generation of evidence regarding the safety of a drug in pregnant women.

Decision-to-delivery interval and neonatal outcomes for category-1 caesarean sections during the COVID-19 pandemic

General anaesthesia is known to achieve the shortest decision‐to‐delivery interval for category‐1 caesarean section. We investigated whether the COVID‐19 pandemic affected the decision‐to delivery interval and influenced neonatal outcomes in patients who underwent category‐1 caesarean section. Records of 562 patients who underwent emergency caesarean section between 1 April 2019 and 1 July 2019 in seven UK hospitals (pre‐COVID‐19 group) were compared with 577 emergency caesarean sections performed during the same period during the COVID‐19 pandemic (1 April 2020–1 July 2020) (post‐COVID‐19 group). Primary outcome measures were: decision‐to‐delivery interval; number of caesarean sections achieving decision‐to‐delivery interval < 30 min; and a composite of adverse neonatal outcomes (Apgar 5‐min score < 7, umbilical arterial pH < 7.10, neonatal intensive care unit admission and stillbirth). The use of general anaesthesia decreased significantly between the pre‐ and post‐COVID‐19 groups (risk ratio 0.48 (95%CI 0.37–0.62); p < 0.0001). Compared with the pre‐COVID‐19 group, the post‐COVID‐19 group had an increase in median (IQR [range]) decision‐to‐delivery interval (26 (18–32 [4–124]) min vs. 27 (20–33 [3–102]) min; p = 0.043) and a decrease in the number of caesarean sections meeting the decision‐to‐delivery interval target of < 30 min (374/562 (66.5%) vs. 349/577 (60.5%); p = 0.02). The incidence of adverse neonatal outcomes was similar in the pre‐ and post‐COVID‐19 groups (140/568 (24.6%) vs. 140/583 (24.0%), respectively; p = 0.85). The small increase in decision‐to‐delivery interval observed during the COVID‐19 pandemic did not adversely affect neonatal outcomes.

The Proportion of Type 2 Diabetic Patients Achieving Treatment Goals and the Survey of Patients' Attitude Towards Insulin In tiation ini Patient s with Inadequate Glycaemic Control with Oral Anti-diabetic Drugs

BACKGROUND

Type 2 diabetic patients often require insulin therapy for better glycaemic control. However, many of these patients do not receive insulin or do not receive it in a timely manner.

OBJECTIVE

The study was planned to assess the proportion of type 2 diabetic patients attaining treatment goals as per the ADA 2018 guidelines. In addition, patient's perception of insulin therapy was assessed and compared between insulin naïve and insulin-initiated type 2 diabetic patients.

METHODS

The study was conducted in type 2 diabetic patients. Data on their demographics, medical history, duration of diabetes, history of diabetes related complications, the current anti-diabetic medication received, and the most recent glycaemic parameters were all noted. Patient's perception of insulin initiation was recorded through a structured interview.

RESULTS

A total of 129 patients were included in the study. Around 76.7% patients achieved HbA1c target (<7%). The duration of the disease is much higher in patients who did not meet the HBA1c target. A good number of patients felt that insulin injection would be physically painful (56.5%). The majority of the patients also felt that insulin would make their life less flexible (64.8%). Many patients have the opinion that insulin is required for life long (73.2%). More number of patients on insulin agreed with the statement 'Leads to good short-term outcomes as well as long-term benefits' compared to insulin naïve patients.

CONCLUSION

The results highlight that the proportion of patients achieving the recommended glycaemic target is not satisfactory. Many patients who are inadequately controlled with oral anti-diabetic drugs were reluctant to initiate insulin.

A Prospective Study of the Clinical and Demographic Profile of Type 2 Diabetes Mellitus Patients Receiving Antidiabetic Drug Combinations

BACKGROUND

The specific treatment recommendations for type 2 diabetes mellitus (T2DM) differ based on a particular guideline. The goal of pharmacotherapy is to achieve the target HbA1c and fasting and postprandial blood glucose levels to avoid disease complications.

OBJECTIVE

To evaluate the profile of T2DM patients on different antidiabetic treatment regimens and the factors leading to dose escalation in these patients.

METHODS

A prospective descriptive study was conducted at Kasturba Medical College Hospital, Mangalore, a tertiary care teaching hospital, over a period of one year. The study population comprised of patients with T2DM for ≥5 years. The demographic and clinical data were collected during the baseline and follow-up visits.

RESULTS

Of the 119 patients studied, 59.7% were males; 32.8% were ≥65 years of age. A significant decrease in the fasting blood glucose (FBG) on follow-up was seen (p = 0.028) in patients on sulfonylurea and metformin combination. A significant decrease in the glycated haemoglobin (HbA1c) was seen in patients on sulfonylurea with metformin and pioglitazone (p = 0.011); sulfonylurea with metformin, pioglitazone, and sitagliptin (p = 0.026); and metformin with insulin (p = 0.001). Patients who received dose escalation had a longer duration of the disease (p = 0.042), higher FBG (p = 0.039) and HbA1c (p = 0.05).

CONCLUSION

A combination of metformin with sulfonylurea was the preferred first-line treatment; insulin was added when HbA1c was >9. Patients who received dose escalation had a longer duration of the disease and higher FBG and HbA1c.

Polypharmacy in Patients with Ovarian Cancer

OBJECTIVE

Polypharmacy has been associated with morbidity and mortality in patients with cancer. Data about polypharmacy among patients with ovarian cancer are limited. The primary objective of this study was to evaluate polypharmacy in a cohort of patients with ovarian cancer and to assess the evolution of polypharmacy from initial presentation to 2 years posttreatment. A secondary objective was to evaluate differences in polypharmacy between a subset of patients primarily treated in our comprehensive cancer center (CCC) and our safety net hospital (SNH).

METHODS

Women treated for ovarian cancer between January 1, 2011, and December 31, 2016, were included. Data were abstracted from the electronic medical record. Medication safety was assessed using the established Anticholinergic Burden (ACB) scale and the Beers criteria. Statistical analyses were performed using paired t tests and Cox proportional hazards models, with significance set at p < .05.

RESULTS

The study included 152 patients. The majority of patients had high-grade serous carcinoma. Hypertension was the most common medical problem. The mean number of medications at the time of diagnosis was 3.72. Paired testing demonstrated significant patient-level increases in the number medications at 2 years following initial diagnosis (4.16 vs. 7.01, p < .001). At the CCC, 47.4% of patients met criteria for polypharmacy at diagnosis compared with 19.4% at the SNH (p < .001). By 2 years postdiagnosis, 77.6% of patients at the CCC met criteria for polypharmacy compared with 43.3% at the SNH (p = .001). The use of any medications on the ACB scale (p < .001) increased significantly between initial diagnosis and 2 years for the entire population. Polypharmacy was not a significant predictor of overall survival.

CONCLUSION

Polypharmacy worsens as women go through ovarian cancer treatment. Both at initial presentation and at 2 years postdiagnosis, rates of polypharmacy were higher at the CCC. Polypharmacy did not have an effect on survival in this cohort.

IMPLICATIONS FOR PRACTICE

Awareness of escalating numbers of medications and potentially adverse interactions is crucial among women with ovarian cancer, who are at high risk for polypharmacy.

Standardization and validation of objective structured practical examination in pharmacology: Our experience and lessons learned

OBJECTIVES

The present study is an attempt to standardize and establish validity and reliability of objective structured practical examination (OSPE) as a tool of assessment in pharmacology.

METHODS

The individual stations were standardized by establishing the blueprint of assessment, checklists for individual OSPE stations, and a review and revision of existing OSPE stations through intensive focus group discussions. Face and content validity was established by subject nonexperts and experts, respectively. Internal construct reliability was assessed using Cronbach's alpha. The scores obtained by the students during their formative sessional examinations were analyzed to calculate Cronbach's alpha, a measure of internal construct reliability and Pearson's coefficient of correlation was used to analyze test-retest reliability and interexaminer reliability. Student and faculty feedback were taken using an open-ended questionnaire.

RESULTS

The Pearson's coefficient of correlation for inter-rater reliability was 0.985, P = 0.0001. The Pearson's coefficient of correlation for test-retest reliability was 0.967, P = 0.0001. Cronbach's alpha values for first, second, and third sessional examinations were 0.825, 0.724, and 0.798, respectively.

CONCLUSION

The faculty and student feedback received was constructive and enabled a systematic review of the existing method and also served as a means to revise the existing curricula.

Whistle Abrasion: A Case Report

Abrasion is the physical wearing of a tooth surface which can involve the presence of a foreign object repeatedly being in contact with the tooth. A 40-year-old male patient reported to our dental clinic with a 2–3 mm uneven gap between his upper and lower front teeth on occlusion. A detailed history revealed that he was a physical education teacher, and the habitual placement of the whistle for the last 15 years caused an indentation on the whistle which coincided with the abraded teeth. Conditions such as abrasion may need active restorations. A general dental practitioner should accurately identify the cause and treat the esthetic and functional impairment as required.

In silico exploratory study using structure-activity relationship models and metabolic information for prediction of mutagenicity based on the Ames test and rodent micronucleus assay

The mutagenic potential of chemicals is a cause of growing concern, due to the possible impact on human health. In this paper we have developed a knowledge-based approach, combining information from structure-activity relationship (SAR) and metabolic triggers generated from the metabolic fate of chemicals in biological systems for prediction of mutagenicity in vitro based on the Ames test and in vivo based on the rodent micronucleus assay. In the first part of the work, a model was developed, which comprises newly generated SAR rules and a set of metabolic triggers. These SAR rules and metabolic triggers were further externally validated to predict mutagenicity in vitro, with metabolic triggers being used only to predict mutagenicity of chemicals, which were predicted unknown, by SARpy. Hence, this model has a higher accuracy than the SAR model, with an accuracy of 89% for the training set and 75% for the external validation set. Subsequently, the results of the second part of this work enlist a set of metabolic triggers for prediction of mutagenicity in vivo, based on the rodent micronucleus assay. Finally, the results of the third part enlist a list of metabolic triggers to find similarities and differences in the mutagenic response of chemicals in vitro and in vivo.

Can Metabotropic Glutamate Receptor 7 (mGluR 7) be a Novel Target for Analgesia?

INTRODUCTION

The present study was carried out to study the role of metabotropic glutamate receptor 7 (mGluR7) using its agonist, N,N'-bis(diphenylmethyl)-1,-ethanediamine (AMN082) for nociceptive stimuli, in animal models. By conducting this research, we aim to introduce a novel target for acute pain management.

OBJECTIVE

To study the role of metabotropic glutamate receptor 7 (mGluR7), in analgesia, using mGluR7 agonist AMN082 in animal models.

MATERIALS AND METHODS

Swiss albino mice of either sex, weighing 20-30gm were used for the study. The animals were divided into 3 groups with 6 mice in each group: Control or Normal group received 0.5% methylcellulose in normal saline; Standard group received the drug tramadol HCl at 40mg/kg; and test group received drug AMN 082 at 5mg/kg. All the drugs were administered by intraperitoneal route. Hot plate test and Tail flick test were done to evaluate the analgesic effect of the drug. Reaction time for the end points in both the models were noted before drug administration at 0 min and after drug administration at 15, 30,60,90 and 120 min. Statistical analysis was done using One-Way-ANOVA followed by Tukeys post hoc test. p-value was considered significant at ≤ 0.05.

RESULTS

The group that received AMN082 showed significantly lesser reaction time compared to normal and standard groups in both the analgesia models.

CONCLUSION

The mGluR 7 stimulation by an agonist AMN082, did not show analgesic effect but induced hyperalgesia in response to thermal nociceptive stimuli.

Combined orthodontic and surgical correction of an adolescent patient with thin palatal cortex and vertical maxillary excess

This paper describes the treatment of a male patient aged 14 years who presented with a skeletal class I, vertical maxillary excess, marked increase in overjet, thin palatal cortex and a gummy smile. Considering the severity of his malocclusion and its impact severity on his psychosocial well being, he was managed with a combined approach of Fixed Orthodontic therapy and Orthognathic surgery, even though his growth was not complete. Records of Pre treatment, Post treatment and three years in retention were analyzed and the functional and esthetic results were found to be fairly stable.

Study of home-monitored night blood pressure and its correlation with left ventricular hypertrophy in treatment-naive hypertensive patients

INTRODUCTION

24-hour ambulatory blood pressure (BP) monitoring is a well-validated tool that can reveal the patient's nocturnal dipping pattern. However, to the best of our knowledge, the role of home BP monitoring in identifying nocturnal dipping has not been studied.

METHODS

We evaluated the nocturnal BP of 30 treatment-naive subjects using a home BP monitoring device. BP measurements were taken once during the daytime and once at night (three hours after sleep) by a blinded observer. Readings were correlated with left ventricular mass index.

RESULTS

Night BP measurements were significantly lower in subjects without left ventricular hypertrophy (LVH) as compared to those with LVH, while the daytime readings were not significantly different between the two. The mean dips in nocturnal systolic and diastolic BP were 1.92% ± 6.89% and -0.55% ± 14.31%, respectively, in subjects with LVH. The corresponding values were 12.96% ± 6.16% and 11.36% ± 11.90% in those without LVH. The correlation between left ventricular mass index and night BP readings was statistically significant (systolic r = 0.66, p < 0.001; diastolic r = 0.496, p < 0.005).

CONCLUSION

Nocturnal BP measurement using a home BP monitoring device may be a reliable and cost-effective method for detecting early signs of end-organ involvement such as LVH in hypertensives, especially in a resource-limited setting.

Optimization of cultural conditions for protease production by a fungal species

Studies were carried out on a paddy soil fungal isolate identified to be a strain of Aspergillus niger from Manipal. The parameters that largely impact enzyme production viz., fermentation time, impeller speed, pH, temperature and nutrient supplements were studied. Optimization of production parameters for production of protease was done by the single-parameter mode. Casein served as substrate and proteolytic activity was estimated using Folin-Ciocalteau method at 660 nm. A maximum yield of 71.3 mg tyrosine/g casein substrate was produced in 96 h on a soluble starch medium at pH 4 in shake flask experiments. Production was carried out on a 3-liter fermenter and 40.7 mg of tyrosine was liberated/g of substrate. The enzyme was extracted with 50% ammonium sulfate and sodium dodecyl sulfate-Polyacrylamide gel electrophoresis showed two bands having mw 45.7 kDa and 38.5 kDa, respectively. The enzyme activity was found to be 147.84 U/ml.

Experimental demonstration of interference avoidance protocol (transmission scheduling) in O-CDMA networks

We experimentally demonstrate a transmission scheduling algorithm to avoid congestion collapse in O-CDMA networks. Our result shows that transmission scheduling increases the performance of the system by orders of magnitude.

Late prosthetic valve endocarditis due to Cardiobacterium hominis, an unusual complication

We report a case of prosthetic valve endocarditis caused by Cardiobacterium hominis in a patient who had undergone atrial septal defect closure and mitral valve replacement of the heart in 1978. He presented with pyrexia of unknown origin and congestive cardiac failure. Investigations revealed infective endocarditis of prosthetic valve in mitral portion. Blood culture samples grew C. hominis. The patient was empirically started on vancomycin and gentamicin intravenously and ceftriaxone was added after isolation of the organism. Though subsequent blood cultures were negative, patient remained in congestive cardiac failure and died due to complications.

Emergency transcatheter balloon recanalization of acutely thrombosed modified Blalock-Taussig shunts

BACKGROUND

Modified Blalock-Taussig shunts are used to palliate a variety of cyanotic heart diseases associated with reduced pulmonary blood flow. Acute shunt thrombosis in patients with shunt-dependent pulmonary blood flow can result in life-threatening hypoxia. We describe our experience of emergency transcatheter recanalization in 5 severely hypoxic children with acute shunt occlusion.

METHODS AND RESULTS

Five patients with ages ranging between 5 and 24 months (median 11 months) and weight ranging from 4 to 8 kg (median 5 kg) presented with severe hypoxia, acidosis and hypotension following acute occlusion of modified Blalock-Taussig shunts placed 11 days to 12 months ago. As severe hypoxia (saturation range 3 5%-5 0%), acidosis and a state of shock in all the patients increased the risk for a redo surgical procedure, they were taken up for emergency transcatheter recanalization within 2-6 hours of hospitalization. This was done by positioning a Judkin's right coronary catheter at the mouth of the thrombosed shunt, crossing the shunt with a guidewire and serial dilatations with coronary and/or peripheral angioplasty balloons to the size of the graft. This technique was immediately successful in 4 of the 5 patients, thereby avoiding a repeat palliative operation. In 2 patients with residual stenosis, stents were used to restore luminal patency. One patient with acute stent thrombosis was managed successfully with local delivery of thrombolysis for 36 hours, which resulted in good luminal patency. At follow-up after 6 and 12 months, the shunts in both the stented patients are patent, with an oxygen saturation of 78% and 80%, respectively. In 2 other patients who had undergone plain balloon angioplasty, the shunts remained patent for 11 days (died of bronchopneumonia and septicemia) and 3 months, respectively. The procedure was unsuccessful in one very sick patient in whom the shunt had a tortuous course.

CONCLUSIONS

Transcatheter recanalization of an acutely thrombosed Blalock-Taussig shunt is feasible. It can offer satisfactory short-term palliation in selected patients. Stents may play a role in patients with residual narrowing after dilatation. The procedure can be expeditiously accomplished in an emergency situation in a severely hypoxic child and may be a realistic alternative to surgery or thrombolysis.

Evidence-based practice. A philosophical and political analysis: some matters for consideration by professional practitioners

This paper evaluates the concept of evidence-based practice (EBP) and appraises critically the implementation process of the EBP initiative, noting its consonance with the aspirations of the dominant political culture and offering a critique of the inherent contradictions and ethical dilemmas associated with it. A critical evaluation of the implications for practitioners and service users is offered and the authors argue that while the concept of EBP is a laudable one, there is a need to exercise caution about uncritical acceptance and evidence that a more eclectic and less reductionist approach to EBP is essential for quality service development.

Percutaneous transvenous mitral commissurotomy using Inoue balloon in children less than 12 years

Rheumatic mitral stenosis in some parts of the world afflicts even young children. Percutaneous transvenous mitral commissurotomy (PTMC) using Inoue balloon in these children is not well reported. Forty-five children (aged 7-12 years, mean 11.0 +/- 1.2 years) with severe rheumatic mitral stenosis (mitral valve area [MVA] 0.64 +/- 0.14 cm2) underwent PTMC. The pulmonary artery wedge pressure (PAW) decreased from 24.3 +/- 8.6 to 14.7 +/- 7.2 mmHg (P < 0.0001) and mean diastolic gradient decreased from 24.3 +/- 7.7 to 7.9 +/- 5.9 mmHg with the final MVA of 1.63 +/- 0.45 cm2 (P < 0.0001). Complications included significant mitral regurgitation (MR) in three children and atrial shunting in two patients. No procedural death, systemic embolism, and cardiac tamponade were encountered. Twenty-four children had maximum balloon size (MBS) same as recommended balloon size (RBS) derived according to the height (group I) and 21 children had MBS 1-3 mm less than RBS (group II). Despite the lesser maximum balloon size, the final results were comparable in both groups (MVA group 1.66 +/- 0.44 vs. group II 1.61 +/- 0.48 P = NS). The incidence of significant MR (2 and 1 in group I and group II, respectively) was similar. On follow-up of 20.4 +/- 16.3 months (range 3-56 months), one child developed restenosis. We conclude that PTMC is safe and effective in children less than 12 years of age. However, the smaller balloon size than the RBS derived from height may be equally effective and possibly safer.

Guide wire outer coat shearing and embolisation: an unusual complication of pericardiocentesis

We report a case of shearing of the outer coat of the guide wire and its embolization into the pulmonary artery during pericardiocentesis. This unusual foreign body was successfully removed by pervenous method.

Effects on tumor cells of ribozymes that cleave the RNA transcripts of human papillomavirus type 18

Many human cervical and oral carcinomas express RNA of human papillomaviruses, and the RNA transcript provides a potential target for gene therapy of these carcinomas. Three hammerhead ribozymes that were targeted to RNA of human papillomavirus type 18 (HPV-18) were cloned into a plasmid expression vector. Each plasmid was then transfected into the HPV-18-expressing cell line. HeLa, or the non-HPV-expressing oral cancer cell line, Tu167. None of the ribozymes had any effect on the phenotype of Tu167 cells. In contrast, each ribozyme affected the phenotype of HeLa cells, causing reduced growth rates, increased serum dependency, and reduced focus formation in soft agar. A molecule that had the same antisense sequences as a ribozyme but lacked the catalytic sequences affected the HeLa cell phenotype to a much lesser extent. The effects of two of the ribozymes could be attributed in part to an increased intracellular concentration of the tumor suppressor protein p53. The most effective ribozyme was targeted to nucleotide 309 in the HPV-18 transcript, but each of the three ribozymes appears to have potential for gene therapy of cancers that express HPV-18.

Effectiveness of three ribozymes for cleavage of an RNA transcript from human papillomavirus type 18

We tested three hammerhead ribozymes for their ability to bind and cleave RNA transcripts derived from the E6 and E7 genes of human papillomavirus (HPV) type-18. Targets were located at nucleotides (nt) 123, 309, and 671 of the viral transcript. In vitro each ribozyme hybridized to its target site when the ribozyme:target ratio was 20:1 or greater and achieved maximal hybridization within 1 hour. HPV RNA from the HeLa cervical cancer cell line was cleaved effectively by each ribozyme. When HPV RNA and a ribozyme were expressed simultaneously in Escherichia coli, each ribozyme produced a significant reduction in the intracellular concentration of HPV RNA. In each assay the ribozyme directed to nt 309 was the most effective. A noncatalytic antisense molecule was used as a control and did not digest HPV RNA or reduce its concentration. The data imply that three different ribozymes each have potential for use in gene therapy of human tumors that express HPV-18 but that the ribozyme targeted to nt 309 is likely to be most effective.

Papillomaviruses as targets for cancer gene therapy

Gene therapy of human cancer is likely to be most effective when it is directed at targets that are expressed in cancer cells but are lacking from other cells. Human papillomaviruses can provide such targets, since these viruses are present in many cervical and oral cancers, and are likely to be etiological agents of the tumor. Continued expression of human papillomavirus genes is probably necessary for the growth of these cancers, and effective gene therapy could consist of antisense or ribozyme molecules directed against these genes. Some human papillomavirus gene products are antigenic, and immunotherapy based upon these antigens might prove clinically beneficial. Human papillomaviruses have specific promoters, are linked to toxin genes, the toxin may be selectively expressed by tumor cells where the virus genes are active. Thus, there are several approaches for the development of specific gene therapy for human cancers that contain human papillomaviruses.