Generic enteral formulas: a new idea for the 1990s

Generic equivalent enteral formulas are now commercially available. The purpose of this article is threefold: (1) to define generic equivalents and compare both their nutritional and monetary differences with brand name products, (2) to provide the clinician with factors to consider when evaluating generic formulas--the source and distribution of macronutrients and micronutrients, and patient tolerance, nutritional status and outcome--and (3) to provide information on how to incorporate generic enteral formulas onto an institution's enteral formulary. In today's environment of diminishing health care budgets, generic enteral formulas can play a role in cost containment without sacrificing quality nutritional care.

New insights into the pathophysiologic condition of venous ulceration with color-flow duplex imaging: implications for treatment?

PURPOSE

This study was conducted to investigate the distribution of reflux in the veins adjacent to or within the venous ulcer (local) and to correlate it with the pattern of disease of the axial veins (all veins away from the ulcer area) of the affected limb.

METHODS

Forty-three ulcers in 34 legs of 33 patients were examined with color-flow duplex imaging. The veins in the area of the ulcer were scanned with a sterile technique.

RESULTS

In 17 legs (50%) there was documented past deep venous thrombosis. All of the 34 limbs had reflux in the superficial or deep axial veins either alone or in combination. Fifteen of these limbs (44%) also had perforating vein incompetence, but none had perforator incompetence alone. Six ulcers showed no evidence of reflux in the local veins when scanned through the ulcer bed despite the presence of reflux in the axial veins of the limb. In 13 limbs with 17 ulcers, either the superficial axial veins alone or the deep axial veins alone were affected (with or without associated perforator incompetence). Examination of the local veins associated with these 17 ulcers revealed a similar pattern of reflux to that seen in the axial veins in 13 cases, with the remaining 4 ulcers showing no local venous abnormality. The pattern of reflux was less predictable at the local ulcer level in limbs where both superficial and deep venous incompetence coexisted in the axial veins. Only 7 of the 26 ulcers (27%) in these limbs had similar evidence of combined superficial and deep reflux in the local ulcer veins, whereas 10 ulcers (39%) were associated with local reflux in the superficial or deep veins alone.

CONCLUSIONS

These data show that 86% (37/43) of the ulcers has some degree of reflux in the local area, the pattern of which may differ from the axial vein disease. Treatment of the local hemodynamic abnormalities may be an important factor in the healing of the ulcers and in the prevention of their recurrence.

Abdominal aortic aneurysm in the Irish population: a familial screening study

A pilot screening programme was undertaken in Ireland to determine the incidence of abdominal aortic aneurysm (AAA) (diameter 3 cm or greater) in the siblings of 120 patients known to have AAA. There were 621 siblings; 270 of them were dead, 32 were over 80 years old and 85 lived outside Ireland, leaving 234 under 80 years of age still living in Ireland who were invited to attend for ultrasonographic screening. Of the 270 siblings who had died, 102 were women and 168 men; eight men (4.8 per cent) had died from ruptured AAA. Only 125 (53.4 percent) of the 234 siblings agreed to participate in the screening programme, 60 brothers from 31 families and 65 sisters from 35 families. Fifteen (12.0 per cent) of the 125 siblings had an AAA (median size 4.2 (range 3.1-6.8) cm), 13 (22 per cent) of the 60 male siblings and two (3 per cent) of the 65 female siblings. The prevalence of AAA among siblings was not affected by the age or sex of the patient with aneurysm. Seven of the 14 male siblings with hypertension had an AAA, compared with only six of the 46 who were normotensive (P = 0.01). The high incidence of AAA in brothers of affected patients highlights the need to counsel this group on their risk of aneurysm. The relatively low participation rate by siblings in this screening programme indicates that a hospital-based unit is unlikely to be effective in recruiting all patient siblings at risk from an AAA.

Biochemical and molecular genetic studies of abdominal aortic aneurysm in an Irish population

Abdominal aortic aneurysm (AAA) is a common disease of the elderly exhibiting a complex aetiology. In a survey of 82 Irish aneurysm patients, compared to 79 age- and sex-matched control subjects, we have investigated a number of potential biochemical and molecular genetic markers which are amenable to analysis from blood specimens and which might have predictive value for AAA. No significant differences were observed between patients and control subjects in relation to serum lipids, leucocyte elastase activity or serum alpha 1-antitrypsin concentration. We have used the polymerase chain reaction to screen the patient and control groups in search of disease-associated genetic variation on chromosome 16, particularly in the region of the Cholesteryl Ester Transfer Protein (CETP) gene. Although variation in allele frequencies was detected between patients and controls at the four marker loci studied, no significant gene-disease associations were detected. The absence of gene-disease associations in our study may indicate that the genetic component in the aetiology of AAA in Ireland differs from that in the UK. Alternatively, it may indicate that the high degree of polymorphism at microsatellite loci may make them unsuitable as markers for the study of gene-disease associations in moderately sized populations. We therefore conclude that the biochemical and molecular genetic markers which we have examined are of no predictive value, and that ultrasonography remains the screening modality of choice for abdominal aortic aneurysm.

[Dosimetric and qualitative evaluations of the use of rhodium filtration in mammography]

The value of rhodium filtration in mammography was compared with that of conventional molybdenum; dosimetric and qualitative tests were performed on a phantom and in vivo on informed and consenting patients. Phantom dosimetric tests confirmed a dose reduction with rhodium filtration changing according to thickness and primary beam energy. With rhodium filtration the dose decreased by 40% on the average topping 67% in breasts thicker than 6.5 cm. No significant differences were observed between rhodium and molybdenum filtration in clinical and phantom qualitative tests. Four radiologists--three of them in double blind--studied 29 mammograms repeated in the same technical setting and expressed a very slight preference for molybdenum also in thick and dense breasts. The slight preference was not based on higher diagnostic yield and therefore clinically irrelevant. Preferences appeared to be subjective, differing from one radiologist to another. In conclusion, the authors suggest the use of rhodium filtration in thick breasts because of the lower administered dose and of shorter exposure time with direct magnification.

Characterization and evaluation of a recombinant hepatitis B vaccine expressed in yeast defective for N-linked hyperglycosylation

The hepatitis B (HB) virus preS2 + 2 polypeptide (the M or middle envelope polypeptide) is N-glycosylated at the N4 residue of the preS2 domain when expressed in recombinant yeast. Hyperglycosylation at this amino acid residue (the addition of a large number of mannose residues to the core oligosaccharide), which occurs in common yeast strains, results in an HB vaccine with diminished immunogenicity. Hyperglycosylation can be prevented by expressing the preS2 + S polypeptide in mutant yeast strains (e.g. mnn9) which limit N-linked glycosylation to the addition of only core saccharide residues. An HB vaccine prepared from recombinant yeast expressing the non-hyperglycosylated preS2 + 2 polypeptide was of similar immunogenicity in mice to a licensed HB vaccine and was much more immunogenic in humans than the hyperglycosylated preS2 + 2 vaccine.

Nitric oxide (endothelium-derived relaxing factor) attenuates revascularization-induced lung injury

Aortic occlusion and revascularization (I-R) may lead to lung injury dependent on activated neutrophil adherence. Nitric oxide (NO) inhibits neutrophil adherence to endothelial cells. We studied the effect of increasing or decreasing NO levels with sodium nitroprusside (SNP) or N-nitro-L-arginine methyl ester (L-NAME) in an I-R lung injury model of 30 min ischemia followed by 120 min reperfusion. Sprague-Dawley rats (10/group) were randomized to controls, I-R, I-R treated with L-NAME (10 mg/ml/hr), and I-R treated with SNP (0.2 mg/ml/hr). Myeloperoxidase activity (MPO) was used as a measure of pulmonary neutrophil influx. Pulmonary endothelial permeability was measured by wet:dry weight ratio and bronchoalveolar lavage protein (BAL prot) and neutrophil counts (BAL PMN). Aortic occlusion and revascularization led to significant increases in pulmonary neutrophil influx (6.1 +/- 0.1 MPO u/g vs 3.05 +/- 0.4 MPO u/g in the control group, P < 0.001) and microvascular leakage; BAL prot (347 +/- 32 mg/ml in controls vs 454 +/- 16 mg/ml in the I-R group, P < 0.05); and BAL PMN (0.7 +/- 0.05 in controls vs 1.8 +/- 0.07 PMN/ml in the I-R group, P < 0.001). These changes were exacerbated further by administration of L-NAME (MPO = 8.9 +/- 0.7; BAL prot = 581 +/- 40 mg/ml; BAL PMN = 2.7 +/- 0.16 PMN/ml). Sodium nitroprusside therapy attenuated the I-R-induced lung injury (3.5 +/- 0.4 MPO u/g, P < 0.05 vs I-R; BAL prot = 330 +/- 61 mg/ml; BAL PMN = 0.9 +/- 0.1 PMN/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Requirement for bowel preparation in colorectal surgery

To determine whether mechanical bowel preparation influences the incidence of anastomotic dehiscence following colorectal surgery, 186 patients undergoing elective left colonic or rectal resection were randomized before surgery to bowel preparation (n = 89) or no bowel preparation (n = 97). Surgical technique was standardized and no patient had a defunctioning colostomy. Seventeen patients were excluded (seven with preparation, ten without). Indications for surgery in the remaining 169 patients were carcinoma (133 patients), diverticular disease (26), inflammatory bowel disease (six) and miscellaneous conditions (four). Operations performed were left colonic resection or reversal of Hartmann's procedure (26 with preparation, 28 without) and anterior resection (56 versus 59). The overall morbidity rate (18 per cent) was similar in the two groups. All seven clinical anastomotic leaks occurred after low anterior resection, in three of the 39 patients who had undergone bowel preparation and four of the 36 who had not (P > 0.9). Two deaths occurred, both of patients who had received bowel preparation, one being secondary to anastomotic leakage. Bowel preparation does not influence outcome after elective colorectal surgery.

How much heparin? A simple in vitro test

A simple in vitro test to calculate the dose of heparin required to achieve optimal in vivo anticoagulation during surgery has been assessed in 15 patients who subsequently underwent vascular surgery. Heparin was added to four aliquots of patients blood in vitro to give five solutions with heparin concentrations ranging from 0-0.8 units/ml of plasma. The activated partial thromboblastic times (APTT) of each of these samples was then measured and the natural log (ln) of the APTT calculated. The natural log of the APTT in vitro was then plotted against the in vitro heparin concentration. From this linear correlation the concentration of heparin required to achieve an APTT 2.5 times the normal in vitro (Hc) for the 15 different patients was calculated and ranged from 0.4-0.75 units/ml (median 0.47). Based on an estimate of the plasma volume (PV), the bolus dose of heparin given intravenously to each patient to produce an equivalent anticoagulant response in vivo was calculated (Hc x PB). Heparin boli administered ranged from 1000-2000 units (median 1500). The mean in vivo APTT achieved was 77% of the predicted value (range 62%-123%). Such an estimation of an in vivo response, by means of an in vitro test, should help to more accurately predict the effects of heparin in vivo and individualise anticoagulation dosage.

[Quality of life following liver transplantation]

247 liver transplantations in 210 patients were done between June 1983 and April 1991 in our hospital. In this paper we have analyzed our experience with adult liver transplantation from the view point of quality of life after liver transplant. Indications for liver transplantation were the following: 46 patients with cirrhosis due to non A, non B hepatitis, 29 with alcoholic cirrhosis, 13 with hepatitis B, 34 with primary biliary cirrhosis, 26 with primary sclerosing cholangitis, 29 with acute hepatic necrosis, 10 with liver tumor, 13 with miscellaneous other diseases. Of the 210 patients, 125 are alive to date. One, three and five year survival rates (excluding perioperative death) of all patients were 80.2%, 70.6% and 65.45% respectively. The best rehabilitation is in 73 patients who are full time workers or full time students and in 16 patients who are homemakers. The degree of rehabilitation in these patients is very high: 6 patients died after achieving complete rehabilitation; 11 patients retired from employment after liver transplantation; 8 patients are chronically disabled; 79 patients died before rehabilitation could be achieved. Rehabilitation rates of one and five year survivors are 78% and 84.2% respectively. Quality of life has been satisfactory following liver transplantation.

[Indications for tubal recanalisation in diagnostic and interventional hysterosalpingography]

Three hundred and seventy-seven hysterosalpingographies performed in 1992 in the Radiology Department of the S. Anna Hospital, Turin, Italy, were reviewed to assess the role and the real incidence of indications to catheterization and to selective salpingography. Proximal tube obstruction treatable by means of extemporary mono-bilateral catheterization was found in 18.3% of cases, but only in 7.4% was catheterization really indicated. In 67.2% of patients repeated contrast medium injections, at high pressure, with the catheter end in front of the internal ostium of the Fallopian tube, allowed recanalization--which made catheterization unnecessary. Catheterization was performed in 18 cases where double injection had failed and was successful in 15 patients (83.3%). Even though selective interventional salpingography is valuable, its use in rarely necessary, especially if conventional hysterosalpingography is performed at the correct injection pressure. Therefore, we conclude that the interventional kit for proximal tube recanalization must always be available, but its use in routine exams is unnecessary.

The management of acute, serous and chronic otitis media: the role of anaerobic bacteria

Otitis media (OM) is a common childhood disease and one which can cause significant morbidity. A knowledge of the pathogens responsible for OM enables the most appropriate treatment regimen to be selected and thus minimizes further complications which may require hospital admission and surgery. The microbiology of acute, serous and chronic OM is reviewed, with particular regard to the role of anaerobic bacteria. Anaerobes, mainly Gram-positive cocci, have been recovered from 25% of the ear aspirates of patients with acute otitis media. In a study of serous OM, anaerobic bacteria were recovered in 12% of the culture-positive aspirates. The predominant anaerobes were Gram-positive cocci and pigmented Prevotella. Several studies have reported the recovery of anaerobes from about 50% of patients with chronic OM and those with cholesteatoma. The predominant anaerobes were Gram-positive cocci, pigmented Prevotella, Porphyromonas sp., Bacteroides spp. and Fusobacterium spp. Many of these organisms produce beta-lactamase which might have contributed to the failure of the patients to respond to penicillins. The appropriate antimicrobial therapy for acute, serous and chronic otitis media is discussed.

[Diagnostic imaging in non-palpable breast lesions. Targeted++ ultrasonography versus direct radiologic magnification]

The main target of mammography in asymptomatic women is the early diagnosis, or rather the identification, of non-palpable breast cancers. Doubtful or suspicious findings on conventional mammograms with no clinical evidence call for radiologic or other complementary imaging techniques to assess the exact lesion nature. Direct magnification and US are targeted techniques to employ as additional investigations after conventional mammography. Fifty consecutive patients were referred to our department of radiology for the preoperative localization of non-palpable breast lesions previously identified on conventional mammograms. The diagnostic or complementary roles of direct magnification and of US were thus investigated. US was always repeated during the preoperative localization; a 10-MHz immersion sectorial probe was used. Magnification was performed if absent or poor in conventional mammograms. The contribution of each technique to conventional mammography was graded as valuable (A), medium (B), or null (C). The lesions were grouped according to their structure: microcalcifications (a), nodules (b), scars (c), and complex lesions (a+b, a+c, b+c, ecc.). Six cases are included in our series which had been diagnosed as questionable or suspicious on previous mammograms. In our department, they were diagnosed as benign. Two of them were operated on because biopsy was required by the gynecologist and the other underwent stereotaxic FNB: negative cytology was considered the final diagnosis. Forty-six histologic and 4 cytologic examinations diagnosed 25 malignant and 25 benign lesions. Direct magnification was of great value in all cases, whereas US was useless in microcalcifications and useful in nodular or complex lesions, especially those with a nodular component. However, the incidence of US false-negatives was high, even in very suspicious cases on mammography, which suggests that US negativity cannot be considered an adequate sign to rule malignancy out.

Selective cholangiography in laparoscopic cholecystectomy

Laparoscopic cholecystectomy is now the method of choice for removing the diseased gallbladder. Asymptomatic common bile duct stones occur in approximately 6 per cent of patients. Controversy exists, however, as to whether selective or routine peroperative cholangiography should be performed during laparoscopic cholecystectomy. Over a 21-month period 300 consecutive laparoscopic cholecystectomies without routine cholangiography were attempted. There were 28 conversions. In all, 229 patients did not undergo cholangiography and in this group there were two common duct injuries. These were both identified and dealt with by open operation. Five patients underwent peroperative cholangiography, none of whom was found to have common duct pathology. Endoscopic retrograde cholangiopancreatography was performed in 38 patients. Of 27 who had this investigation performed before operation, common duct stones were diagnosed in seven (26 per cent). Two common duct stones were discovered in 11 patients who underwent the investigation after operation. Thus only two of 240 patients (0.8 per cent) who did not undergo preoperative or peroperative cholangiography subsequently had symptomatic duct stones. Peroperative cholangiography may be indicated in selected patients who have had symptoms of common bile duct stones or in those in whom the biliary anatomy is unclear. However, routine preoperative or peroperative cholangiography is unnecessary during laparoscopic cholecystectomy.