A novel ribozyme target site located in the HIV-1 nef open reading frame

We have tested the sequence UUC CAG UCA GAC CU, at position 9016--9029 within the HIV-1(SF2) nef open reading frame, for accessibility to antisense and hammerhead ribozyme attack. The accessibility was first studied using a phosphorothioate-modified 14-nt DNA oligo (complementary to the nef9016--9029 site). A dose-dependent repression of HIV-1(SF2) growth was observed in human peripheral blood mononuclear cells after exogenous administration of the oligo to the cell culture medium. A hammerhead ribozyme with a 6+7-nt antisense specificity for the nef9016--9029 site (hhRz.nef9016--9029) was constructed and transfected into the human T-cell line HUT78. Again, a dose-dependent repression of virus growth was observed when different individual clones expressing hhRz.nef9016--9029 were infected with HIV-1(SF2). A complete abrogation of virus production was observed after infection with a low (0.5 TCID50) HIV-1 titer. Increasing doses (2.5 and 12.5 TCID50) of HIV-1 virus yielded a low production (10(3)-fold reduced) of virus particles in most cases; but a complete, or close to complete, abrogation was observed even in individual cultures infected with the highest dose. Presence of proviral pol and gag sequences in hhRz.nef9016--9029-expressing HUT78 clones was assayed, using PCR. Interestingly, since no pol and gag PCR products could be detected, the results strongly indicated that the hammerhead ribozyme was already acting on the infecting HIV RNA before its reverse transcription and integration as proviral DNA. In summary, the results obtained in this study support the nef9016--9029 site as a strong new candidate for ribozymal gene therapy against HIV-1 infection.

Replacement of the ascending aorta with composite valve grafts: long term results

BACKGROUND AND AIMS OF THE STUDY

Long term survival after replacement of the aortic root is improving. The most common cause of late death is progression of disease in the remaining aorta (dissection or atherosclerosis). The purpose of this study was to review our clinical experience with composite graft replacement of the aortic root with special reference to long term results.

MATERIALS AND METHODS

One hundred twenty-six patients (mean age: 53 years) with different pathologies of the ascending aorta underwent aortic root replacement with a composite-graft prosthesis over a 12-year period. Twenty-three patients had previously undergone cardiovascular surgery. The surgical technique included resection of the ascending aorta with the aortic valve and end-to-side anastomosis between full-thickness buttons of the aortic wall with the coronary ostia and the graft. One or more associated cardiovascular procedures were performed in 24 cases. Long term follow up to July 1995 is complete. Uni- and multivariate analysis were performed to identify risk-factors for early and late mortality and reoperation.

RESULTS

Twenty-three patients died during the first 30 days (18%). Sixteen of them had aortic dissection. The most common cause of early death was heart failure. Twenty-three patients died during the follow up time with heart failure, again, being the most common cause of death. Thirteen late reoperations on the composite-graft or the remaining aorta were performed in 12 patients, six of whom had Marfan's syndrome. The 30-day mortality at reoperation was 30%.

CONCLUSIONS

This surgical option offers good long term results with a five-year actuarial survival of 67% or 75% when the 30-day mortality is excluded. Careful follow up of patients with Marfan's syndrome and/or aortic dissection is mandatory to increase the long term survival.

Development of 123I-labelled NNC 13-8241 as a radioligand for SPECT visualization of benzodiazepine receptor binding

[125I]- and [123I]NNC 13-8241 were prepared from the trimethyltin precursor and radioactive iodide using the chloramine-T method. The total radiochemical yields of [125I]- and [123I]NNC 13-8241 were 60-70% and 40-50% respectively, with radiochemical purity higher than 98%. In binding studies with [125I]NNC 13-8241 in rats in vitro and in vivo a high uptake of radioactivity was demonstrated in brain regions known to have a high density of benzodiazepine (BZ) receptors such as the occipital and frontal cortex. SPECT examination with [123I]NNC 13-8241 in a Cynomolgus monkey demonstrated a high uptake of radioactivity in the occipital and frontal cortex. After displacement with flumazenil radioactivity in these brain regions was reduced to the level of a central region including the pons. Four hours after injection about 80% of the radioactivity in monkey plasma represented unchanged radioligand. This low degree of metabolism indicates that NNC 13-8241 is metabolically more stable than the radioligands hitherto developed for imaging of BZ-receptors in the primate brain.

Intestinal parasites in children and adults with and without abdominal discomfort from the Kathmandu area of Nepal

The present study on intestinal parasites from the Kathmandu area of Nepal found that in subjectively healthy children (HC) and adults (HA) the total parasite load was 28.1% and 38.8%, respectively, whereas children (ADC) and adults (ADA) with abdominal discomfort had a load of 62.7% and 67.8%. The prevalence of nematodes in the 4 groups was significantly higher in those with abdominal discomfort, particularly of Hookworm, Enterobius, and Ascaris. Hymenolepis nana was the most common tapeworm, and also with the highest incidence in patients with abdominal complaints. Taenia solium and T. saginata were only found in the two adult groups, but with low prevalence rates. The highest incidence of Cryptosporidium was found in both groups with abdominal discomfort, notably among children. No "healthy" carriers were found among the adults, whereas the prevalence of "healthy" carriers among children corresponded to that of sick adults. The presence of Giardia was highest among the sick children, many "healthy" carriers among both children and adults were noted. E. histolytica and E. dispar had a surprisingly low prevalence in all 4 groups. In "healthy" children the parasite was twice as common than in sick, supporting earlier findings of morphologically identical species with and without pathogenicity. "Healthy" adults had the lowest prevalence and sick adults the highest in the 4 groups studies. Blastocystis hominis was most common among adults with abdominal complaints (2.8%). Trichomonas was also more common in this group, in which of 34 positive specimen, 28 were from women. In "healthy" children the prevalence of mixed parasite infection was 2.1%, in "healthy" adults more than 7%, while in sick children and adults the prevalence was 13.3% and 11.5%, respectively.

Factors influencing haemostasis and blood transfusion in cardiac surgery

To find out the risk factors influencing perioperative bleeding and use of blood products in cardiac surgery so that appropriate interventions can be selected for blood conservation, risk factors were analysed in 343 cardiac surgical patients, retrospectively, by multiple regression technique. The results showed that the factors related to postoperative bleeding were male gender, Higgins score, cardiopulmonary bypass (CPB) time, operation procedures, intraoperative blood loss and use of internal mammary artery (IMA) graft. Factors related to perioperative homologous blood transfusions were emergency surgery, preoperative haemoglobin level, Higgins score, intraoperative blood loss, operation time and operation procedures. The geometric mean of postoperative bleeding in the entire series was 1085 ml and the mean packed red cell, plasma and platelet transfusions were 3.29 +/- 0.4, 1.96 +/- 0.39 and 0.21 +/- 0.05 units respectively. The incidence of homologous blood transfusion during the hospital stay was 58.9% for the entire series and 54.5% in the nonrevision patients. Emergency patients received significantly more blood transfusion (p = 0.0001). Perioperative blood loss and transfusions are still problems in cardiac surgery and certain patient groups in this study were identified as high risk; available blood conservation techniques, therefore, are recommended in these patients.

Preoperative echocardiographic prediction of small prosthesis size for aortic valve replacement

BACKGROUND AND AIMS OF THE STUDY

Prosthesis size is known to have an effect on long term outcome after heart valve replacement. We evaluated 115 patients subjected to aortic valve replacement to assess the ability by preoperative echocardiography to identify patients having small aortic roots and thereby likely to receive a small prosthesis (size 19 or 21), previously shown to be associated with a worse prognosis.

METHODS

From an initial part of the study (Group A), comprising 67 patients, we evaluated the influence of image quality on the accuracy for prediction of patients receiving a small prosthesis. In a second series of 48 patients (Group B), we tested the predictive value of various limits of aortic annulus diameter to define patients at risk of receiving a small prosthesis.

RESULTS

The measurement of aortic annulus diameter in Group A gave a reasonable correlation to subsequent prosthetic dimension (r = 0.73, n = 59). However, there was a considerable variation of echocardiographic aortic annulus diameter among patients receiving prostheses of the same size. In Group B, an aortic annulus diameter of < or = 22 mm correctly identified 10 of 13 patients receiving a small prosthesis (sensitivity 77%). Twenty-two of 25 patients (88%) with an aortic annulus diameter > 22 mm received a large prosthesis.

CONCLUSIONS

We conclude that the echocardiographic measurement of the aortic annulus diameter is a fairly sensitive method to identify patients receiving a small prosthesis. However, the predictive accuracy is dependent upon training as well as image quality. Furthermore, the value of planning in advance the type of prosthesis, annuloplasty or homograft for aortic valve replacement remains to be shown.

The influence of seat-back and head-restraint properties on the head-neck motion during rear-impact

The influence of different seat properties on the head-neck motion during a low-velocity rear-end impact was tested using a Hybrid III-dummy fitted with a modified neck (RID-neck). The results show that by modifying the properties of the seat-back and head-restraint it is possible to influence the head-neck kinematics to a great extent. It was possible to virtually eliminate the neck extension motion during a rear-impact. This will hopefully result in a significant decrease in neck injury risk in real world rear-impacts.

Cytomegalovirus-induced CD13-specific autoimmunity--a possible cause of chronic graft-vs-host disease

Cytomegalovirus (CMV) infection has been suggested to be associated with certain autoimmune phenomena as well as with the development of chronic graft-versus-host disease (cGVHD) following allogeneic bone marrow transplantation. Earlier we found that the CMV-associated host protein CD13 is immunogenic during CMV infection in allogeneic bone marrow transplant patients, resulting in production of CD13-specific antibodies (7). Here we found a close correlation between CD13-specific immunity and later development of cGVHD in 26 of 33 patients who could be evaluated for this disease. Of seven patients with CMV disease, six developed extensive cGVHD, all of whom had CD13 specific antibodies (P=0.0002). All 14 patients who were CD13-immune later developed either limited or extensive cGVHD (P=0.0008). Antibodies in sera from the CD13-immune patients suffering from cGVHD recognized normal structures in cryosectioned skin biopsies from control individuals, producing a staining pattern similar to that of CD13-specific monoclonal antibodies. The antibody binding could be specifically blocked by preincubation of the skin sections with a mixture of monoclonal antibodies against CD13, and was also abolished after preabsorption of sera to mouse cells expressing human CD13. No other common autoantibodies were identified in more than single patients. Furthermore, in vivo binding of IgM antibodies in a CD13-like fashion was preferentially demonstrated in skin and oral mucosa biopsies from the CD13-immune patients suffering from cGVHD. Thus, we suggest that CMV-induced CD13-specific autoimmunity contribute to tissue damage in chronic graft-versus-host reactions.

Endemicity and clinical picture of liver disease due to obstruction of the hepatic portion of the inferior vena cava in Nepal

Obstructive lesion of the hepatic portion of the inferior vena cava is common in Nepal. The clinical data on 150 patients who were seen at the Liver Unit, Bir Hospital, Kathmandu, in three years from 1990 to 1992 were analysed. Although the majority of patients were over 20 years of age, 25 patients were below 10 years of age; there were more males than females in this study. This disease accounted for 17% of 866 patients with chronic liver disease and for nearly one quarter of 267 biopsies performed on this patient group during the same period. Obstructive lesions of the inferior vena cava seem to be more common among poor people with malnutrition. Clinically, our patient group could be divided into acute (n = 27), subacute (n = 43) and chronic (n = 80) cases. The important clinical features are hepatomegaly and/or ascites and, in chronic cases, prominent dilated superficial veins over the body trunk with cephalad flow. Ultrasound is the most helpful diagnostic procedure, especially in subacute and chronic cases, as it frequently demonstrates caval obstruction, thrombosis, dilated hepatic veins and intrahepatic collaterals. Diagnosis is confirmed by cavography, which shows a caval obstruction of varying lengths at the cavo-atrial junction or a marked narrowing of the hepatic portion of the vena cava. In subacute and chronic cases cavography also demonstrates collateral veins, such as the ascending lumbar, hemiazygos and azygos that drain into the superior vena cava. Chronic cases had periods of exacerbation often associated with bacterial infection. The aetiology of inferior vena cava obstruction at its hepatic portion is not known, but there seems to be a frequent association of bacterial infection with the disease.

The role of palliative radiotherapy in advanced head and neck cancer

The role of radiotherapy in the palliation of patients with advanced cancer of the head and neck is not clear. Several distinctive characteristics of advanced head and neck cancer contribute to the complexities in the choice of appropriate palliative management strategies. Palliative treatment may be the appropriate management for a proportion of patients with advanced disease, but the current stage groupings of head and neck cancer are not sufficient for use in the reliable identification of such a patient group. Controversy arises because of the difficulties in distinguishing patients who should be offered conventional treatment with curative intent from those appropriate for treatment with palliative intent. A structured review of the cancer and quality of life literature identified 298 references pertaining to palliative radiotherapy in head and neck cancer, 26 of which met the criteria for inclusion in this review. An expert panel discussed the literature, and concluded that insufficient information precluded estimations of the frequency, degree of, or duration of symptomatic relief that radiation offered to those patients not cured of their disease. Moreover, the currently available literature does not address the toxicity or appropriate dose and fractionation of palliative radiotherapy in this setting. Further studies are necessary to evaluate clinical endpoints appropriate to the use of radiotherapy in the palliative management of patients with advanced head and neck cancer. Studies are also needed to refine the current clinical classification of patients, allowing the identification of patients suitable for palliative management.

Lung cancer in West Sweden 1976-1985. A study of trends and survival with special reference to surgical treatment

We reviewed 3 285 consecutive cases of lung cancer diagnosed in West Sweden during the period 1976-1985. Data were collected from the regional cancer registry, the Swedish National Population Registry, and medical records. During the study period, the annual female/male ratio increased from 0.29 to 0.42. In females, there was an increase primarily in the incidence of tobacco-related morphologic tumour types (i.e. squamous and small cell lung cancers). In males, a moderate increase of adenocarcinomas was seen, although squamous cell cancer remained the most common tumour type. The overall 5-year survival rate was 8.3%. In 641 patients (20%) a surgical tumour resection was carried out. The 5-year survival rate following resection was 38%, and the probability of 10-year survival was estimated at 25%. In a multifactorial model including gender, age, histology, pTNM stage and extent of resection, pTNM stage and, to a lesser degree, age were statistically significant independent predictors of postoperative survival. The five-year survival was 57% in stage 1, 21-27% in stage II and IIIa, and 10% in stage IIIb. Of all resected patients, 4.2% died within two months after resection. In males, early postoperative mortality was predicted by preoperative bicycle ergometry. The prognosis in non-resected patients was poor, with only 2% surviving 5 years or longer. In conclusion, the results indicate that some progress has been made with regard to surgical management of lung cancer, but they also point to the fact that the vast majority of patients are not amenable to curative treatments, and that the overall survival in lung cancer has improved only marginally during the last decades.

Preoperative gastric emptying. Effects of anxiety and oral carbohydrate administration

BACKGROUND

Overnight fasting is routine before elective surgery. This may not be the optimal way to prepare for surgical stress, however, because intravenous carbohydrate supplementation instead of fasting has recently been shown to reduce postoperative insulin resistance. In the current study, gastric emptying of a carbohydrate-rich drink was investigated before elective surgery and in a control situation.

METHODS

Twelve patients scheduled for elective surgery were randomly given 400 mL of either a carbohydrate-rich drink (285 mOsm/kg, 12.0% carbohydrates, n = 6) or water 4 hours before being anesthetized. Gastric emptying was measured (gamma camera, 99Tcm). Each patient repeated the protocol postoperatively as a control. All values were presented as the mean +/- SEM by means of a nonparametric statistical evaluation.

RESULTS

Despite the increased anxiety experienced by patients before surgery (p < 0.005), gastric emptying did not differ between the experimental and control situations. Initially, water emptied more rapidly than carbohydrate. However, after 90 minutes, the stomach was emptied regardless of the solution administered (3.2 +/- 1.1% [mean +/- SEM] remaining in the stomach in the carbohydrate group versus 2.3 +/- 1.2% remaining in the stomach in the water group).

CONCLUSIONS

Preoperative anxiety does not prolong gastric emptying. The stomach had been emptied 90 minutes after ingestion of both the carbohydrate-rick drink and water, thereby indicating the possibility of allowing an intake of iso-osmolar carbohydrate-rich fluids before surgery.

Comparison of the mechanical performance of three types of external fixators: linear, circular and hybrid

Different configurations of the Monticelli-Spinelli and Ilizarov external fixation systems were tested to define their mechanical properties. In five configurations the external fixator consisted of rings with tensioned wires (circular), while in one configuration two pairs of the tensioned wires and their correspondent ring were replaced by threaded pins (hybrid). Testing was performed in axial compression, bending and torsion. The results were compared to the characteristics of a selected linear fixator group. Both the circular and the hybrid configurations were non-linear in compression. In bending, circular fixators had a similar pattern in both anteroposterior and oblique loading directions. The bending load-displacement pattern for the hybrid fixators was similar to the linear fixators, higher stiffness in the plane of the pins. Torsion was linear for both circular and hybrid fixators, as for the linear fixators. By combination of wires and pins (hybrid configuration), the mechanical behaviour had characteristics from both linear and circular fixators. It is concluded that the three studied groups own different mechanical performance and can be considered as different types of fixators. While it has been demonstrated that osteogenesis can be achieved independently of the mechanical behaviour of the fixator, this study supports the suggestion that some complications can be related to the mechanical behaviour of the fixator.

Epidemiology of scapular fractures. Incidence and classification of 338 fractures

We have studied scapular fractures, with special reference to intraarticular glenoid fractures, during a 10-year period in 2 Swedish counties. There were 338 scapular fractures in 322 patients. The annual incidence was 10/10(5) inhabitants, of which 30 percent affected the glenoid cavity. Out of 100 intraarticular glenoid fractures, 55 occurred in men and 45 in women. The mean age of the women at the time of fracture (64 years) was significantly higher than the mean age of men (49 years). The most common intraarticular glenoid fracture type was the anterior chip fragment fracture which, in about two-thirds of the cases, was associated with shoulder dislocation.

Infected tibial nonunion. Good results after open cancellous bone grafting in 37 cases

We treated 37 infected tibial shaft nonunions by debridement followed by open autogenous cancellous bone grafting in a 2-stage procedure. Additional surgery was done in 21 fractures including second debridement before bone grafting and/or a second limited bone grafting and/or a split-thickness skin grafting. All fractures healed after an average of 11 (8-16) months. During 2 years follow-up there were no recurrences of the infection. Two cases of early refracture occurred, both healed following new bone grafting.

Circulating leukocyte adhesion molecules in stable asthma and nonobstructive chronic bronchitis

Leukocyte adhesion molecules have been associated with airway inflammatory diseases such as asthma and obstructive chronic bronchitis. Lately, it has become possible to measure circulating forms of cell adhesion molecules (cCAMs) in body fluids. Elevated serum levels have been found in acute asthma and in obstructive chronic bronchitis. We investigated whether the patterns of cICAM-1, cVCAM-1, and cE-selectin could serve as markers for airway inflammation in stable asthma and stable nonobstructive chronic bronchitis. Small-volume bronchial lavage (BL) and serum from 15 controls, 13 asthmatics without steroid inhalation therapy, 11 asthmatics with regular steroid inhalation therapy, and 10 smokers with chronic bronchitis were analyzed. We found cICAM-1, cVCAM-1, and cE-selectin to be present in serum from patients with stable asthma and stable nonobstructive chronic bronchitis. Only cICAM-1 was found in BL fluid. No differences were seen between the subject groups for either cCAM, but levels of ECP were increased in the non-steroid-treated asthmatic group. Subject atopy or smoking did not increase the cCAM levels. In conclusion, the degree of airway inflammation in stable nonobstructive chronic bronchitis and stable asthma does not appear to be well associated with circulating ICAM-1, cVCAM-1, and cE-selectin.

The CuA center of cytochrome-c oxidase: electronic structure and spectra of models compared to the properties of CuA domains

The electronic structure and spectrum of several models of the binuclear metal site in soluble CuA domains of cytochrome-c oxidase have been calculated by the use of an extended version of the complete neglect of differential overlap/spectroscopic method. The experimental spectra have two strong transitions of nearly equal intensity around 500 nm and a near-IR transition close to 800 nm. The model that best reproduces these features consists of a dimer of two blue (type 1) copper centers, in which each Cu atom replaces the missing imidazole on the other Cu atom. Thus, both Cu atoms have one cysteine sulfur atom and one imidazole nitrogen atom as ligands, and there are no bridging ligands but a direct Cu-Cu bond. According to the calculations, the two strong bands in the visible region originate from exciton coupling of the dipoles of the two copper monomers, and the near-IR band is a charge-transfer transition between the two Cu atoms. The known amino acid sequence has been used to construct a molecular model of the CuA site by the use of a template and energy minimization. In this model, the two ligand cysteine residues are in one turn of an alpha-helix, whereas one ligand histidine is in a loop following this helix and the other one is in a beta-strand.

Mechanical versus biological valve prosthesis: a ten-year comparison regarding function and quality of life

To determine the long-term outcome of biological and mechanical heart valve prostheses, we compared the Biocor, a new generation of porcine bioprosthesis, with the St. Jude Medical mechanical prosthesis. One hundred consecutive patients operated on between 1983 and 1985 with the Biocor in the aortic, mitral, or both positions (without concomitant cardiac procedures) were followed until January 1993, together with 100 matched patients implanted with the St. Jude valve. The mean age was 66 and 67 years, respectively. The follow-up was 100% complete. Valve-related mortality differed significantly, with a freedom rate of 80.7% +/- 9.0% for the St. Jude group and 97.7% +/- 1.6% for the Biocor group. There were few thromboembolic events, with no significant difference between the groups. Anticoagulant-related hemorrhage occurred almost exclusively in the St. Jude group (2.3%/patient-year), and reoperations were required almost exclusively in the Biocor group (1.8%/patient-year). The occurrence of all valve-related complications (mortality plus morbidity) differed markedly, with an actuarial freedom at 10 years of 55.8% +/- 9.8% for St. Jude and 80.0% +/- 4.4% for the Biocor. Quality of life and echocardiographic measurements did not differ significantly between the groups. We conclude from this study that the long-term performance of the Biocor and St. Jude are comparable, even though valve-related complications tended to be fewer in the Biocor group, with a significantly lower incidence of valve-related death.

Similar quality of life after heart valve replacement with mechanical or bioprosthetic valves

The goal of this study was to determine if there was a difference in the quality of life (QoL) between patients receiving bioprosthetic (Biocor, BIO) or mechanical (St. Jude Medical, SJM) valve prosthesis. In January 1993 we assessed the psychological outcome of heart valve surgery among 183 (87 BIO, 96 SJM) of 220 survivors in a selected and matched cohort of 140 BIO and 140 SJM recipients who had their valve replacement between 1983 and 1989. The BIO and SJM groups were equal in terms of mean age, gender, valve position, educational level, marital status and follow up time. Questions concerning QoL, in terms of coping capacity, social support, and general emotional status as well as emotions concerning valve-related complications, were answered by the patients marking a non-graded visual analogous scale, ranging from total agreement to total disagreement. We found no significant difference between patients receiving BIO and those receiving SJM prostheses regarding coping capacity (62 +/- 2 vs. 65 +/- 2), social support (77 +/- 3 vs. 76 +/- 2), or emotional status (63 +/- 3 vs. 65 +/- 3). When subdividing patients by age below and above 60 years, gender, functional class, valve position and complication, we found several significant differences, but the two prosthetic groups were largely similar. Females had a significantly lower level of coping capacity and emotional status than males. Coping capacity and emotional status were significantly correlated with functional class, while social support was not. Coping capacity tended to be lower among patients who had experienced complications and this was more pronounced with BIO.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of closed tibial shaft fractures with unilateral external fixation

Sixty-eight closed tibial shaft fractures were treated with an anterior unilateral external fixator over a 5 year period (1986-1991). Pin tract drainage and/or infection was seen in 71/380 pins. The total number of secondary operations, excluding planned pin extraction, during fracture healing was 61 (including 22 due to pin tract problems and 25 secondary corrections of alignment). Delayed union was seen in 14 fractures and non-union in three. Healing disturbances were more frequent following high-energy trauma. Bone grafting was done in 11 fractures. Eventually, all fractures healed within an average of 22 weeks. There were three refractures. At follow-up, on average 3 years after injury, functional results were excellent in 41 per cent, good in 46 and acceptable in 13 per cent. Due to the high number of unplanned secondary operations and prolonged healing times we do not consider the use of unilateral external fixation to be an adequate method for the treatment of closed tibial shaft fractures. The poor results are probably due to weight-bearing being too high in these patients relative to the mechanical stability provided by the external fixator system.