[The correlations between color Doppler using a contrast medium and the neoangiogenesis of small prostatic carcinomas]

PURPOSE

To investigate if the use of a contrast agent (Levovist) improves the specificity of US in the diagnosis of prostate carcinoma, having the results of prostate biopsy as the gold standard.

MATERIAL AND METHODS

Thirty patients with physical findings suspicious for prostate carcinoma and PSA ranging 5 ng/mL to 15 ng/mL were examined with transrectal US (TRUS) integrated with the color Doppler mode and contrast agent administration (4 g injected at 4 mL/min: 300 mL concentration).

RESULTS

Based on bioptic and surgical results, 14 prostate carcinomas were found, all of them < 1.2 cm. Conventional US recognized the suspected nodule in 11 cases, with 78% sensitivity and 93% specificity. Color Doppler showed color signals in 8/14 cases, which were peripheral to the lesion or intranodular, but did not add any important finding to those of gray-scale US. In contrast, contrast enhanced studies showed 13/14 carcinomas, which improved sensitivity significantly (92%). Particularly, 11/14 lesions had a typical avascular pattern within the strongly enhanced peripheral gland, while 2 small lesions only exhibited intranodular vessels.

DISCUSSION AND CONCLUSIONS

We compared our results with the Microscopic Angiogenesis Grading System (MAGS) index and found it exceeded 30 in the 11 avascular lesions value indicates microneoangiogenesis. In the other two cases a value < 30 was correlated with a different type of tumor vascularization typical of macroangiogenesis.

[Dysmetabolic syndrome related to HIV-1 protease inhibitors. Review of the literature and personal data]

HIV-positive patients receiving antiretroviral therapy with HIV-1 protease-inhibitors (PI) frequently show insulin-resistance, impaired glucose tolerance, hypertriglyceridaemia and lipodystrophy (LD). LD has often been reported only after the beginning of PI therapy. Some authors link LD to HIV chronic infection, some others suggest that PIs increase pre-existent disturb. Preliminary data of an observational study drawn in IV day-hospital of Spallanzani Institute in Rome showed hypertriglyceridaemia in 36.4% and hyperglycaemia in 11.2% of patients treated with PI. Carr suggests that such drugs should have this lipid-increasing effect because of their inhibition of low density lipoprotein-receptor-related protein, cytoplasmic retinoic-acid binding protein type 1 and P450 3A cytochrome. This theory doesn't explain why both untreated patients and treated with only reverse transcriptase inhibitors show sometimes the same disorders. According to another hypothesis Tumor necrosis factor-alpha, through inhibition of lipoprotein-lipase, would determine high fat-storage in the adipose tissue. Cardiovascular risk factors have always to be assessed before starting a therapy with PI. Glycaemia, triglyceridaemia, cholesterolaemia have to be performed every three months during the treatment and, if necessary, C-Peptide and insulinaemia too. A treatment with lipid-lowering drugs is always recommended in patients with hypertriglyceridaemia > 500 mg/dl and/or hypercholesterolaemia LDL > 190 mg/dl in two following checks. Fibrates have proven to be effective in reducing hypertriglyceridaemia, but there is no certainty that such therapies could have good effects on the LD itself too.

A new model to assess tcpO2 changes during heat-dependent vasodilation: preliminary observations

The transcutaneous pO2 (tcpO2) changes induced by the increase of temperature to 45 degrees C after electrode stabilization at 37 degrees C were continuously recorded. The mathematical analysis of the curve led us to identify three different parameters: the half-slope "b" time, the angular "mT" coefficient and the angular "mb" parameter, which are not simply the expression of the maximum vasodilation capacity but mainly of the dynamic response of the microcirculatory system to skin heating. These parameters derived from the computerized mathematical analysis of the curve can be also obtained by a graphical approach with a very good approximation. The angular "mb" coefficient was shown to possess the highest statistical power in discriminating the POAD patients from normal controls. The clinical relevance and the possible pathophysiological meaning of these preliminary observations have to be confirmed.

Pharmacokinetic and immunogenic behavior of three recombinant human GM-CSF-EPO hybrid proteins in cynomolgus monkeys

MEN 11,300, MEN 11,301, and MEN 11,303 are three recombinant human hybrid proteins that, as has recently been described, induce in vitro erythroid differentiation. This article provides data on their pharmacokinetic and immunogenic behavior after repeated i.v. administration to cynomolgus monkeys at 0.8 or 1.6 micrograms/kg doses. Pharmacokinetic data, obtained after the first administration, showed that the half-life (t1/2) and clearance (CL) values are dose dependent, with no significant differences among the three hybrid proteins. After the tenth administration, MEN 11,300 and MEN 11,301, both a high and low dose, and MEN 11,303 at high dose were undetectable in plasma, whereas MEN 11,303 at the lower dose showed no alteration in its pharmacokinetic profile. Immunologic analyses of plasma provided an explanation for this different pharmacokinetic behavior. In fact, plasma samples from animals treated repeatedly with MEN 11,300 and MEN 11,301 showed specific antibody formation in response to both the high- and the low-dose regimens. These antibodies exerted in vitro a strong neutralizing activity of the hybrid proteins, with a predominant specificity for the erythropoietin (EPO) portion. By contrast, MEN 11,303 at the lower dose did not induce a detectable antibody response whereas the antibodies observed on the high-dose regimen did not exert neutralizing activity against the hybrid proteins nor against granulocyte-macrophage colony-stimulating factor (GM-CSF) or EPO. Hematologic parameters were not affected by the treatments, thus indicating that the anti-EPO neutralizing antibody response does not cross react with the endogenous monkey cytokine. The overall immunogenicity data suggest that among the three fusion proteins, MEN 11,303 could have a lower immunogenic potential.

[Insulin resistance. Receptor and post-receptor abnormalities]

Insulin action starts with binding to a membrane receptor (insulin receptor-tyrosine kinase) and with activating an insulin receptor substrate 1 (IRS-1) and substrate 2 (IRS-2). Insulin receptors interact at least with three cascade reactions, phosphorylating G proteins and IRS-1, that activate PLC "ras" and PI-3-K. NIDDM can be defined as a disease caused by defective transduction of insulin signals and IR as a complex phenotype manifesting itself, emphasized by individual and environmental factors, in the cellular systems of signal transduction. IRS is a syndrome characterized by NIDDM, hypertension, visceral obesity, CHD: the X syndrome. Up to day the described mutations of the insulin-receptor gene are rare (e.g. the leprechaunism): genetic IR. Obesity is the principal cause of IR by receptorial and post-receptorial defects: metabolic IR. The obese skeletal muscle shows a reduction of insulin receptor and IRS-1 phosphorylation and of PI-3-K activation; the scarce expression of these proteins would determine the muscular IR. IR is a pattern of essential hypertension. Hypertension, dyslipidemia and abnormality of glucose metabolism are linked by IR. The so called high erythrocyte Na(+)-Li+ counter-transport is a new biochemical marker for IR and hypertension. These drugs can reduce IR: metformin, sulphonilureas, fibrats, dexfenfluramine, troglitazone, doxazosin, ACE-inhibitors.

Amiloride pharmacokinetics in rat

The kinetics of amiloride was investigated in plasma, urine, faeces and tissues of rats after oral (10 mg/kg) and i.v. (10 mg/kg bolus and 35 microg/h for 4-days infusion) administration. Initially the experimental data were analyzed by a multiexponential model, then a compartmental model was developed to describe the drug kinetics in plasma, urine, faeces and tissues after the i.v. bolus and the oral administration simultaneously. Aim of the model was also to predict the drug kinetics in plasma and tissues of rats after continuous i.v. infusion. The results of the prediction and the discrepancies between prediction and observed data allowed a deeper insight into the pharmacokinetics of amiloride.

Artificial skin equivalent differentiation depends on fibroblast donor site: use of eyelid fibroblasts

Our objective was to construct and explore human skin equivalents from several normal and pathologic donor skin sites to determine if the fibroblast origin influences epidermal differentiation. Also, we wanted to find out if fibroblasts from some donor sites produced epidermis of superior quality for plastic surgery repairs. Skin equivalents were constructed from 15 normal skin specimens, 9 normal eyelid specimens, 15 lesional skin specimens taken from patients with psoriasis, and 4 specimens from keloid scars. Results show that the tissue origin of the donor fibroblasts determines epidermal differentiation and the time period for regeneration. Eyelid fibroblasts were very dependable in establishing well-differentiated skin equivalents in all nine specimens. Our findings contribute to the accumulated knowledge of wound healing and should also be of value in skin grafting, especially when large areas are denuded as in burns, severe trauma, or cancer ablation.

Pharmacokinetics of isosorbide dinitrate in healthy volunteers after 24-hour intravenous infusion

No studies have examined the pharmacokinetics of isosorbide dinitrate (ISDN) after infusion of long duration, even though such infusions are used in patients. We therefore measured ISDN and its active metabolites, isosorbide-5-mononitrate (IS5MN) and isosorbide-2-mononitrate (IS2MN), in plasma of 9 healthy volunteers who received a continuous intravenous infusion of ISDN for 24 hours at a dose rate that lowered diastolic blood pressure by 10% during the first 30 minutes of infusion. All subjects tolerated the infusion except one who experienced intolerable headache. Five subjects received 1 microgram.min-1.kg-1, one 2 micrograms.min-1.kg-1, and two 4 micrograms.min-1.kg-1 ISDN, whereas the full rate of 6 micrograms.min-1.kg-1 was used continuously in one subject. At all infusion rates the plasma concentrations of ISDN were higher at 24 hours than at earlier times, suggesting that a steady-state condition had not been reached at that time. The same was true for the mononitrate metabolites, which reached higher plasma concentrations and were cleared more slowly than the parent compound after the end of the infusion. Apparent elimination half-lives of ISDN, IS2MN, and IS5MN were 67 +/- 10 minutes, 115 +/- 13 minutes, and 272 +/- 38 minutes, respectively. Comparison of low-rate infusions (1 and 2 micrograms.min-1.kg-1) with high-rate infusions (4 and 6 micrograms.min-1.kg-1) showed that the plasma concentration ratios at 24 hours of mononitrate metabolites to parent drug and apparent plasma clearance of ISDN were almost halved at the higher infusion rates.

Endoscopic approach to traumatic visual loss

OBJECTIVE

To review our experience with the use of endoscopic optic nerve decompression in traumatic blindness.

METHOD

We did a retrospective analysis of patients with traumatic blindness that underwent endoscopic decompression of the optic canal to determine postoperative visual acuity and correlate it to preoperative visual loss and intraoperative findings. The setting was a Level I university trauma center. We identified 8 patients treated with both surgery and steroids over a 10-month period beginning in 1993 (Seven males, one female).

RESULTS

Four of six patients with total blindness (no light perception) had improvements in visual acuity. In three patients, visual acuity returned to preinjury levels. One patients with total blindness was operated on 6 weeks after injury and had a visual acuity of 20/800 at 1-year follow-up. Two patients with hand motion preoperatively had improvement in visual acuity. In one patient, vision returned to normal (20/20), and in the other it improved to 20/200). Five patients were operated on after megadose steroid treatment for at least 48 hours failed; four of five noted dramatic improvements in visual acuity.

CONCLUSION

The endoscopic approach may be used to successfully decompress the optic nerve in traumatic blindness.

Multiple genetic lesions in solid tumors: relevance to diagnosis, prognosis, and molecular mechanisms

In recent years, significant progress has been made in identifying characteristic chromosomal and molecular rearrangements associated with several solid tumors. Most solid tumors studied have been found to be characterized by recurrent chromosomal abnormalities that are specific to histologic types. We have studied primary specimens of malignant melanoma, gastrointestinal cancer, renal carcinoma, lung and ovarian cancer, by cytogenetic and molecular means, and we discuss the genetic alterations found. Brief descriptions of the potential clinical utility, and biological relevance changes in these disorders are also discussed.

[The pharmacokinetics of antibiotics: parenteral and oral administration, distribution in the organism, elimination]

The efficacy of antimicrobial therapy is largely dependent on the pharmacokinetics of the drug. Pharmacokinetics is the study of the kinetics, that is of the movements of drugs in the body fluids and tissue cells. Often, despite the complexity of mammalian organism, relatively simple compartmental systems are capable to describe the kinetics of many drugs and to provide a rationale in interpreting the experimental results. As most bacterial infections are localized in tissues, the pharmacokinetic modelling of antimicrobial agents should mainly be devoted to clarify the relationship between plasma and tissue drug levels, the former being easily accessible to sampling and the latter more closely related to therapeutic efficacy. In this paper an introduction to pharmacokinetic modelling is presented and the pharmacokinetics of many antimicrobial drugs is discussed.

Pharmacokinetics of exogenous adenosine in man after infusion

The plasma kinetics of adenosine was investigated in healthy volunteers after a 1 minute infusion of 2.5, 5 and 10 mg (38.79 and 148 micrograms.kg-1 respectively) and after infusion of 200 micrograms.kg-1 in 10 min followed by 400 micrograms.kg-1 in 10 min. As the dose in the 1 min infusion study was increased the mean CL of adenosine decreased (10.7, 4.70 and 4.14 l.min-1, respectively), its mean half-life increased (0.91, 1.24 and 1.86 min, respectively), and the mean volume of distribution did not show any clear trend (8-13 l). After the 20 minute infusion the plasma level of adenosine reached a peak value comparable to that observed after infusion of 5 mg in 1 min (about 0.5 micrograms.ml-1), but the mean clearance and half-life were significantly different (12.1 l.min-1 and 0.63 min respectively). In all the subjects the plasma concentration of adenosine had returned to the baseline value in 5-15 min after the end of the infusion.

Anesthesiologic findings in surgery for the treatment of trauma of the pelvis

The authors discuss the numerical increase in fractures of the acetabulum and the extent of surgical indications for their treatment, emphasizing the modernness and the usefulness of methods used to save blood in this type of surgery, which often involves a considerable loss. Out of 150 operations performed between 1985 and 1990 for trauma of the pelvis, 35% of the patients was not transfused with homologous blood, 25% was transfused with 1 U, 40% with several units (4.7 U on the average). Generally, the average quantity of erythrocytes transfused per patient was 2 U (440 ml).

[Sodium naproxen in postoperative pain in orthopedics. Comparison of 2 different doses]

In order to use etiopathogenetic criteria for the treatment of postsurgical pain, non-steroid anti-inflammatory drugs (NSAIDs) can be used rather than narcotic analgesics. These agents are often classified as peripherally acting analgesic drugs; nevertheless in the last years many pages have who showed a central supraspinal analgesic effect. Sodium naproxen is commonly used in the treatment of postoperative orthopedic pain because of its pharmacokinetic properties. The aim of this study was to evaluate the suitable dosage of sodium naproxen for post-surgical pain relief. Forty patients submitted to foot surgery were randomized into two groups of 20 patients each. At the end of surgery one group of patients (group I) received sodium naproxen 275 mg i.m.; the same dose was administered after 12 hours. A second group (group II) received sodium naproxen 550 mg i.m. at the same time intervals. Based on a Descriptive scale for algometric measurements, the results showed significant differences in analgesic activity for the two treatments. The best results (70% of patients with no pain or slight pain vs 20% of patients) were obtained in the group that received sodium naproxen at the higher dosage (p less than 0.001). No differences were observed in the incidence of side-effects in the two groups. These results are discussed.

The treatment of congenital hip dislocation between the ages of 1 and 3

A total of 81 patients (103 hips) with a diagnosis of congenital hip dislocation were reviewed, who had been treated between one and three years of age. All of the patients were initially treated with adhesive band traction prior to non-surgical reduction, which was performed under general anesthesia using gentle reduction maneuvers followed by immobilization in plaster. Non-surgical reduction was performed in 69 hips (67%), surgical in the remaining 34 (33%). A total of 91 associated surgical procedures were performed for the treatment of residual subluxation. Average follow-up was 12 years (minimum 5, maximum 19). The clinical results of the non-surgical reductions were excellent in 75% of the cases. Radiographically, 48% are hips which have a normal aspect, while 42% have a moderate degree of residual dysplasia or deformity of the femoral epiphysis and of the acetabulum. Hips that were initially classified as grade III dislocations show fair results. Hips treated non-surgically included 11 cases of avascular necrosis (16%); recovery was adequate. Hips treated surgically included 14 cases of avascular necrosis (30%), which was more accentuated in those hips that had initially been treated elsewhere, and in those classified as grade III. The clinical and radiographic results obtained for the hips treated surgically demonstrate poor results in 17% of the cases (6 out of 34), as a consequence of types III and IV osteochondrosis. It may be concluded that in this age group congenital hip dislocation is best treated by non-surgical reduction, possibly followed by surgery of the femur and acetabulum. Surgical reduction was only indicated when conservative methods failed.

Pharmacokinetics of heptastigmine in rats

Heptastigmine is a new long acting cholinesterase inhibitor that affects behaviour in a number of cognitive tests in animals. We have studied its pharmacokinetics in rats: plasma kinetics were evaluated after single intravenous dose (2 mg/kg), intramuscular (4 mg/kg) and oral (4 and 8 mg/kg) administration. Tissue distribution (heart, liver, kidney and brain) was studied after single intramuscular (4 mg/kg) and oral (8 mg/kg) administration. Plasma and tissue kinetics were also investigated after repeated oral doses (8 mg/kg b.i.d. for 7 days). Heptastigmine levels in plasma and tissues were determined using an HPLC method with an electrochemical detector. After a single dose, heptastigmine remained for a long time in plasma (the terminal half-life was about 12 h), distributed widely in tissues (the volume of distribution was about 61) and brain concentrations were very high (4-22 times those found in plasma). After repeated oral doses, the drug levels increased in plasma and, to a lesser extent, in liver and kidney.

Pharmacokinetics of rufloxacin in healthy volunteers

The plasma and urine kinetics of rufloxacin were assessed in healthy volunteers after single (100, 200, 400 and 800 mg) and multiple (300 mg followed by 150 mg daily, Group 1, and 400 mg followed by 200 mg daily, Group 2) oral doses. The kinetics of a single oral dose of 800 mg was assessed in fasting and non-fasting subjects to assess the influence of food intake on drug absorption. The AUCs were 134, 266 and 375 micrograms.h.ml-1 after 100, 200 and 400 mg, respectively. The AUC after 800 mg p.o. was 715 micrograms.h.ml-1 in fasting subjects and 614 micrograms.h.ml-1 in non-fasting subjects. The parameters of the model and the mean renal clearance values indicated some departure from linearity in rufloxacin kinetics. After multiple doses the plasma drug levels during the 6th treatment day were similar to those after the first dose in Group 1 and were about 30-40% higher after the first dose in Group 2. The half-lives after the last dose were much shorter than those estimated in the single dose studies (33-36 h and 50-80 h, respectively).