Guidance for statistical design and analysis of toxicological dose-response experiments, based on a comprehensive literature review

The analysis of dose-response, concentration-response, and time-response relationships is a central component of toxicological research. A major decision with respect to the statistical analysis is whether to consider only the actually measured concentrations or to assume an underlying (parametric) model that allows extrapolation. Recent research suggests the application of modelling approaches for various types of toxicological assays. However, there is a discrepancy between the state of the art in statistical methodological research and published analyses in the toxicological literature. The extent of this gap is quantified in this work using an extensive literature review that considered all dose-response analyses published in three major toxicological journals in 2021. The aspects of the review include biological considerations (type of assay and of exposure), statistical design considerations (number of measured conditions, design, and sample sizes), and statistical analysis considerations (display, analysis goal, statistical testing or modelling method, and alert concentration). Based on the results of this review and the critical assessment of three selected issues in the context of statistical research, concrete guidance for planning, execution, and analysis of dose-response studies from a statistical viewpoint is proposed.

Realization of nanoscaled tubular conductors by means of GaAs/InAs core/shell nanowires

We investigated the transport properties of GaAs/InAs core/shell nanowires grown by molecular beam epitaxy. Owing to the band alignment between GaAs and InAs, electrons are accumulated in the InAs shell as long as the shell thickness exceeds 12 nm. By performing simulations using a Schrödinger-Poisson solver, it is confirmed that confined states are present in the InAs shell, which are depleted if the shell thickness is below a threshold value. The existence of a tubular-shaped conductor is proved by performing magnetoconductance measurements at low temperatures. Here, flux periodic conductance oscillations are observed which can be attributed to transport in one-dimensional channels based on angular momentum states.

Use of terazosine in patients with chronic pelvic pain syndrome and evaluation by prostatitis symptom score index

PURPOSE

Chronic Pelvic Pain Syndromes (CPPS) affect an important percentage (5-9%) of the patients in urology practice; however there has been no consensus as to how the treatment should be planned in these patients. The purpose of our study is to evaluate the effectiveness of terazosine in the treatment of CPPS patients.

MATERIALS AND METHODS

In our outpatient department, between May 1997 and October 1999, 91 patients were diagnosed as CPPS. These patients were first evaluated by Prostatitis Symptom Score Index (PSSI) and then randomized into two treatment groups. The first group received 2 mg/day terazosine (47 patients), and the others received placebo (42 patients). After three months of treatment, 69 patients came back for the control visit (terazosine 39, placebo 30). They were reexamined by PSSI and their results were evaluated by Wilcoxon analysis.

RESULTS

Before the treatment PSSI of the 39 patients who received terazosine were 9.61 +/- 1.61, after the treatment they were 6.25 +/- 1.60. For the placebo group, PSSI values before the treatment were 9.27 +/- 1.88 and after the treatment they were 8.81 +/- 2.66. In the terazosine group, the difference between the pretreatment and post treatment PSSI values was statistically significant (p = 0.0002). In the placebo group, on the other hand, this difference was statistically insignificant (p = 0.701)). After the treatment, the difference between the terazosine and placebo groups was also statistically significant (p = 0.001). In the terazosine group (as the recommendation was to take the medication at night) postural hypotension did not develop.

CONCLUSION

Terazosine was effective for the treatment of CPPS. However it was concluded that three months of treatment was insufficient.

Bullet embolism of the right external iliac artery following cardiac gunshot wound (a case report)

Penetrating cardiac injury (PCI) frequently cause hemorrhage and cardiac tamponade. However peripheral embolization is very rare. In this manuscript one of the rare case of bullet embolism in the right external iliac artery, which occurred after cardiac gunshot wound is reported under the light of literature.

Renal hydatid cyst and situs inversus totalis (a case report)

Although echinococcal disease is common in some parts of the world isolated renal involvement is rare. We present a single case of a renal hydatid cyst in a patient with situs inversus totalis.

[Evaluation of patients wounded in the 17 August 1999 Marmara earthquake]

This study describes the experience of Kartal Research and Training Hospital in the Marmara Earthquake. We reviewed medical records of 698 patients admitted to our hospital in a 30 days' period after the earthquake and analysed the types of injuries, treatment, morbidity and mortality rates. The hospitalized 273 patients were grouped according to the major injury; patients with crush syndrome were analysed separately. The most frequent injuries were crush injury (23.1%), extremity fractures (16.8%) and pelvis and spine injuries (16.1%). More than two system injuries were seen most frequently in the abdominal injury (45.5%), crush injury (24.4%), and pelvis and spine injury (27.3%) groups (p < 0.05). Overall mortality rate was 7.3%. The highest mortality rates were seen in the abdominal injury (27.3%) and crush injury (20%) groups (p < 0.05). 61.9% of the patients with crush syndrome underwent fasciotomy due to the compartment syndrome; hemodialysis was performed in 31 patients. The most serious problem with earthquake is organization in the earthquake area, between hospitals and in hospitals. Crush injury is the major injury seen earthquakes. Early diagnosis and proper treatment should be done to improve survival.

Anatomic study of posterior interosseous nerve in the arcade of Frohse

To verify the precise anatomy of the radial tunnel, 60 cadaver elbows were dissected with special reference to 7 parameters: (1) the distance between the lateral intermuscular septum and the site of division of radial nerve into its superficial and posterior interosseous branches was 92 mm (85 to 120 mm), (2) the length of the posterior interosseous nerve from its division to the arcade of Frohse (AF) was 46 mm (35 to 65 mm), (3) the average distance between the radial head and AF was 21 mm (17 to 30 mm), (4) the average length of its branch to the extensor carpi radialis brevis muscle from its division to AF was 28 mm (20 to 45 mm), (5) the average distance of the supinator branch from its division to AF was 21 mm (15 to 28 mm), (6) the relationship between the posterior interosseous nerve and the recurrent radial artery showed several variations, and (7) the texture of AF was fibrous in 80% and was membranous in 20%. We recommend that anatomic variations should be kept in mind to avoid complications during radial tunnel surgery.

Peyronie's disease: intralesional treatment with interferon alpha-2A and evaluation of the results by magnetic resonance imaging

In this clinical study, to determine the therapeutic efficacy of interferon (IFN) treatment for Peyronie's disease, we applied interferon alpha-2A (IFN alpha-2A) intralesionally in the treatment of Peyronie plaques in 15 patients and results were evaluated by magnetic resonance imaging (MRI). Patients whose plaque sizes were 0.5 and 1 cm responded better to the treatment. There was about a 90% lessening in the sizes of the plaques of 1.5 cm, 83.3% of 2 cm, as the ones which were 0.5 cm and 1 cm disappeared completely after treatment. As a conclusion, the treatment of Peyronie's disease with IFN alpha-2A is effective and side effects are minimum.

Fournier's gangrene: review of fifteen cases

Fournier's gangrene is a synergistic necrotizing fasciitis of the perineum and abdominal wall along with the scrotum and penis in men and the vulva in women. The process was believed to be idiopathic in initial descriptions. Fifteen patients were treated for Fournier's gangrene between 1990 and 1995 in the Departments of General Surgery and Urology, School of Medicine, Atatürk University, Erzurum, Turkey. The most common causes were perianal sepsis and urogenital diseases. Escherichia coli and Staphylococcus aureus were identified most commonly in cultures of necrotic tissue. The mortality rate was 20 per cent despite aggressive surgical debridement and broad-spectrum antibiotics.

Pharmacotherapy of benign prostatic hyperplasia: inhibitor of 5 alpha-reductase

We studied the effects of 5 alpha-reductase inhibitor (finasteride) in the treatment of benign prostatic hyperplasia (BPH). This study is a randomized controlled trial. Sixty-two patients were treated with 5 alpha-reductase (finasteride 5 mg/day) and 61 patients (control group) with placebo for one year. Prostatic volume, maximal urine flow rate, AUA symptom scoring, residual urine volume and prostate-specific antigen (PSA) levels were evaluated at 3, 6, 9 and 12 months. In the first 6 months prostatic volume decreased rapidly (20.5%), in the second 6 months it decreased slowly and reached the maximal rate (23.3%). Maximal urine flow rate increased in the second 6 months. AUA symptom scores decreased first at 3 months and were 4.6 points lower at the end of the 12th month. There were no significant changes in residual volume. The 5 alpha-reductase inhibitor caused a 50% decrease in PSA levels, like in other studies. Because of the prolonged use of the drug, treatment with 5 alpha-reductase inhibitor is not tolerated by many patients and being expensive its future in the pharmacotherapy of BPH is unclear.

Iatrogenic injuries to ureter, bladder and urethra during abdominal and pelvic operations

Abdominal and pelvic operations at Departments of Obstetrics and Gynaecology, and General Surgery play an important role in ureteral, bladder and rarely urethral injuries. Fifty-nine patients with iatrogenic ureteral, bladder and urethral injuries were treated at the Department of Urology, Atatürk University Research Hospital, between 1985 and 1995. These injuries were urinary vaginal fistulas in 43 patients (vesicovaginal 33, ureterovaginal 7, urethrovaginal 2 and vesicovaginal plus urethrovaginal 1), ureteric ligation in 9, bladder laceration in 7. These injuries were treated by different methods. All patients were followed up by intravenous urography (IVU) and urine culture three months later. It must be borne in mind that iatrogenic urinary tract injuries are not rare. Bladder and ureteral catheterization must be performed to prevent these complications.

The effects of thiotepa, mitomycin C, BCG and interferon instillation on urothelium

The effects of Thiotepa, Mitomycin C, BCG and Interferon on urothelium were researched in rabbits. Early changes of a contracted bladder such as fibroblastic atypia and sub-epithelial plaque were seen in all groups in different rates. This rate in the Thiotepa and BCG groups was 100% and in the Mitomycin C and Interferon groups 60%. There was no urothelial dysplasia in the BCG and Interferon groups, whereas in the Thiotepa group 100% and in the Mitomycin C group 40% were seen. In conclusion, urothelial dysplasia or fibroblastic atypia in random biopsies were criteria to prevent further complications in intravesical therapies.