Inhibition of HIV-1 replication in macrophages by red blood cell-mediated delivery of a heterodinucleotide of azidothymidine and 9-(R)-2-(phosphono methoxypropyl)adenine

Monocyte-derived macrophages (M/M) are considered important in vivo reservoirs for different kinds of viruses, including HIV. Hence, therapeutic strategies are urgently needed to protect these cells from virus infection or to control viral replication. In this paper, we report the synthesis, target delivery and in vitro efficacy of a new heterodinucleotide (AZTpPMPA), able to inhibit HIV-1 production in human macrophages. AZTpPMPA consists of two established anti-HIV drugs [zidovudine (AZT) and tenofovir (PMPA)] chemically coupled together by a phosphate bridge. This drug is not able to prevent p24 production when administered for 18 h to M/M experimentally infected with HIV-1 Bal (inhibition 27%), but can almost completely suppress virus production when given encapsulated into autologous erythrocytes (inhibition of p24 production 97%). AZTpPMPA is slowly converted to PMPA, AZT monophosphate and AZT (36 h half-life at 37 degrees C) by cell-resident enzymes. Thus AZTpPMPA should be considered a new prodrug of AZT and PMPA that is able to provide stechiometric amounts of both nucleoside analogues to macrophage cells and to overcome the low phosphorylating activity of M/M for AZT and the modest permeability of PMPA.

Estimating mean pulmonary wedge pressure in patients with chronic atrial fibrillation from transthoracic Doppler indexes of mitral and pulmonary venous flow velocity

OBJECTIVES

We sought to obtain a noninvasive estimation of mean pulmonary wedge pressure (MPWP) in patients with chronic atrial fibrillation (AF).

BACKGROUND

It has previously been demonstrated that MPWP can be reliably estimated from Doppler indexes of mitral and pulmonary venous flow (PVF) in patients with sinus rhythm. Doppler estimation of MPWP has not been validated in patients with AF.

METHODS

MPWP was correlated with variables of mitral and pulmonary venous flow velocity as assessed by Doppler transthoracic echocardiography in 35 consecutive patients. The derived algorithm was prospectively tested in 23 additional patients.

RESULTS

In all patients the mitral flow pattern showed only a diastolic forward component. A significant but relatively weak correlation (r = -0.50) was observed between MPWP and mitral deceleration time. In 12 (34%) of 35 patients, the pulmonary vein flow tracing demonstrated only a diastolic forward component; a diastolic and late systolic forward flow was noted in the remaining 23 patients (66%). A strong negative correlation was observed between MPWP and the normalized duration of the diastolic flow (r = -0.80) and its initial deceleration slope time (r = -0.91). Deceleration time > 220 ms predicted MPWP < or = 12 mm Hg with 100% sensitivity and 100% specificity. When estimating MPWP by using the equation MPWP = -94.261 PVF deceleration time -9.831 Interval QRS to onset of diastolic PVF -16.337 Duration of PVF + 44.261, the measured and predicted MPWP closely agreed with a mean difference of -0.85 mm Hg. The 95% confidence limits were 4.8 and -6.1 mm Hg.

CONCLUSIONS

In patients with chronic AF, MPWP can be estimated from transthoracic Doppler study of PVF velocity signals.

Should total prosthetization of the patella be used in knee surgery? A review of the literature and personal experience

Based on an analysis of patellar complications during total knee arthroplasty, the authors report the conclusions of the most important studies in the literature as to whether or not the patella should be prosthetized. In particular, several important parameters to be taken into consideration before performing patellar prosthetization are discussed: the conditions of the cartilage and of the patellar bone, preoperative clinical symptoms, age, habits, body weight of the patient. The results of 50 Miller-Galante prostheses implanted between January 1989 and September 1993 is reported. The patella was prosthetized in 40% of the cases; there were no fractures or vascular necroses, nor was there breakage or detachment of the prosthetic button. Patellar pain was manifested in 5 cases (10%), 2 of which with a prosthetized patella, including 1 case of external dislocation and 1 case of breakage of the patellar tendon; another case of external dislocation, in a non-prosthetized patella, was clinically asymptomatic; pain was manifested after delay in wound healing in 2 cases. Only one patient with breakage of the patellar tendon was submitted to further surgery. The authors conclude that in light of the numerous studies published prosthetization of the patella may offer overall better clinical results, but they advise that indications should be carefully evaluated for each individual case, and that details in surgical technique should be observed (correct execution of bone resection and of lateral release when necessary, preservation of Hoffa pad, accurate hemostasis).

[Complete regression of Barrett's esophagus after drug therapy]

Barrett's esophagus is defined as a disorder in which the normal stratified squamous mucosa of the esophagus is replaced by columnar epithelium. Patients with Barrett's esophagus are at risk to develop an adenocarcinoma of the esophagus. Pathologic gastroesophageal reflux is correlated to the disease and therapeutical options must aim to stop this noxa in order to prevent columnar metaplasia, and subsequent dysplasia and/or neoplasia. The Authors report the case of a patient in whom the complete regression of the metaplasia was observed after medical therapy.

[Neonatal hemoperitoneum: role of ultrasonography. Experience with 4 cases]

This study was aimed at investigating the role of US in the newborn with a clinical suspicion of hemoperitoneum. Hemoperitoneum is a dramatic clinical event which may be caused by some obstetrical and fetal factors--breech or complicated delivery, hepatomegaly, macrosomy, anoxic liver congestion being the most frequent causes. Direct or indirect trauma of an abdominal organ during delivery represents the major pathogenetic factor. Clinical symptoms are correlated with the appearance of shock whose intensity is proportional to trauma severity: symptoms may appear even 48 hours after delivery. The authors report their experience with 4 consecutive cases of neonatal hemoperitoneum which underwent US of the abdomen 24 to 72 hours after birth. In the first 3 newborns, US was performed on the basis of a clinical picture of bleeding shock, while in the extant newborn US was performed after a sudden increase in blood transaminase level associated with an obstetrical paralysis of the left arm. The US examinations were performed using a 7.5-MHz sectorial probe unit (Siemens). In all patients, US demonstrated the presence of a liquid effusion in the abdomen which could be referred to hemoperitoneum. In two patients, it was associated with a traumatic focal alteration of the liver parenchyma, in the third with a diffuse subcapsular liver hematoma and, finally in the fourth patient with a disconnected splenic vascular pedicle which was at surgery demonstrated. In conclusion, US is indicated as the most reliable and valuable diagnostic technique in the study of neonatal hemoperitoneum. The authors believe abdominal US to be essential in all the neonatal cases where hemoperitoneum is suspected and in selected cases presenting specific risk factors, to allow a rapid diagnosis and better treatment planning.

Estimation of left ventricular diastolic pressures from precordial pulsed-Doppler analysis of pulmonary venous and mitral flow

Because analysis of pulmonary venous flow (PVF) will be extensively used in comprehensive Doppler assessment of left ventricular diastolic function, this study was designed to (1) evaluate the feasibility of PVF measurement in 116 consecutive patients with various cardiac abnormalities by using precordial pulsed Doppler echocardiography; (2) Estimate mean pulmonary capillary pressure (MPCP) and left ventricular end-diastolic pressure (LVEDP) from Doppler variables of PVF and mitral inflow; and (3) evaluate the influence of clinical and hemodynamic variables on PVF Doppler patterns. We adequately recorded anterograde PVF in 96 (82.7%) patients and retrograde PVF in 45 (38.7%) patients. The strongest correlation between MPCP and Doppler variables of PVF was found with systolic fraction (the systolic velocity time integral expressed as a fraction of total anterograde PVF) (r = -0.88; p < 0.001). Age influenced this relation, with progressive increase of the systolic fraction in older patients. A good correlation (r = 0.72; p < 0.001) was found between LVEDP and the difference in duration of the reversal PVF and the mitral a wave. In conclusion, (1) PVF can be recorded adequately in most patients with precordial Doppler echocardiography; (2) left ventricular diastolic pressures can be estimated reliably by precordial Doppler echocardiography; and (3) the clinical meaning of Doppler-derived indexes of left ventricular diastolic performance is age-related.

The Miller-Galante knee prosthesis system: a review of 42 cases

The authors report their experience in 42 total Miller-Galante knee prostheses; 40 of the prostheses have an average follow-up of 25 months (minimum 9, maximum 55). Based on the Hungerford-Kenna clinical evaluation system, 59% of the patients obtained excellent results, 26% good results, 10% fair results, and 5% poor results. Radiographically, there were no cases of loosening of the implant. The joint axis was always well-corrected. A total of 12% of the patients complained of patellar pain (3 cases without either a prosthesis or keiloplasty; 2 cases with a patellar prosthesis). Overall, 85% of the patients obtained excellent or good results.

[Trauma: when the liver "ruptures".... Our experience of 125 cases]

Liver and spleen are the organs most frequently involved in the blunt abdominal trauma. Prognosis is severe in those cases classified as IV or V according to the More score. The imaging techniques, particularly CT scan, offer today a possibility in the nonoperative management of a selected group of haemodynamically stable patients, therefore reducing the need of surgery. The authors' experience in 125 patients observed from 1983 to 1991 is reported.

[Mirizzi's syndrome type II: a diagnostic and therapeutic problem]

The paper reports a case of cholestatic icterus caused by a large calculus in the infundibulum of the gallbladder with a cholecysto-choledochal fistula and hepato-choledochal block (Mirizzi's type II syndrome). The diagnostic iter complicated the evolution, raising questions regarding the therapeutic strategy.

Allograft revision surgery of failed hip replacements: X-ray pattern and clinical results

The authors describe their experience with allograft in 23 cases of revised hip replacements, paying particular attention to the clinical results and the X-ray appearance. They conclude by emphasizing the particularity of the surgical technique and the various factors involved in the use of bone grafts in such elective surgery as hip replacement.

The Grosse-Kempf nail in femoral and tibial shaft fractures

Interlocked nailing is a routine method that yields excellent results even in complex fractures of the lower limb. A series of 25 femoral and 29 tibial fractures is reviewed, and both advantages and technical difficulties are discussed. The authors point out that, in very special cases, interlocking nails may be used together with other methods of internal and external fixation.

[Primary intrahepatic calculosis: hepatic lithotomy or hepatectomy?]

The authors discuss about the different surgical approaches in the management of primary intrahepatic stones, conforming their experience to literature reports. In the future they hope for a more conservative treatment on the basis of the good results obtained with percutaneous transhepatic fiber cholangioscopy (P.T.C.S.) and ultrasonographic extra-body lithotripsy recently adopted in the clinical practice.