Utility of a rapid lamellar body count in the assessment of fetal maturity.

The authors investigated the use of a recently described method for the rapid determination of the lamellar body count (LBC) as a means of evaluating fetal pulmonary maturity. Results of the rapid LBC were compared, alone and in combination with the foam stability index (FSI), with the results obtained by thin-layer chromatography (TLC). The study used 90 consecutive amniotic fluid specimens from 82 patients. Rank ordering of the data suggested cutoff points of 19,000/microL for the rapid LBC and 46 for the FSI. Statistical analysis indicated that the addition of the LBC improved the sensitivity of the FSI (P less than 0.01 by the McNemar test), although the reverse was not the case (P greater than 0.1). The linearity and reproducibility of the LBC were considered acceptable.

Extramedullary plasmacytoma (amyloid tumour) of the caruncle.

An 81-year-old man presented with a globoid caruncular mass of recent onset involving the left medial canthus. Pathological examination of the mass after its complete excision showed a roughly spherical subepithelial tissue deposit of amyloid, surrounded and sparsely infiltrated by plasma cells. The amyloid showed permanganate-resistant congophilia consistent with immunamyloid, and since most of the plasma cells stained positive for lambda light chains on immunohistochemical cytoplasmic staining, with no demonstrable heavy chains, the lesion was regarded as an extramedullary amyloid-producing plasmacytoma. Its solitary appearance in our patient, who has remained disease free, probably predicts the favourable prognosis generally associated with such lesions.

Ultrastructure of cardiac bacterial vegetations on native valves with emphasis on alterations in bacterial morphology following antibiotic treatment.

Bacterial vegetations involving the aortic valves of six patients were studied by scanning and transmission electron microscopy. The microorganisms isolated were Staphylococcus aureus--2, coagulase-negative staphylococcus--1, Streptococcus fecalis--2 and Streptococcus MG--1. The surface of the vegetations was usually amorphous. However, in areas where the surface of the vegetation was broken, myriads of microorganisms were seen. Transmission electron microscopy revealed bacteria embedded in an electron dense matrix in all vegetations despite the fact that they were negative on culture. Cell wall rupture was common. Thinning, and in some instances thickening, of the cell wall was also observed. The Streptococcus MG cells showed abnormal division with daughter cells being unable to separate. It is likely that the altered morphology of these bacterial cells is due to antibiotic treatment, however studies of an animal model of endocarditis are needed to dissect out the various possible contributions to these changes: host defenses; bacterial malnutrition in the depths of the vegetation; and antibiotic effect.

Is duplicate testing for prothrombin time and activated partial thromboplastin time necessary?

To evaluate the necessity of duplicate testing for prothrombin times (PTs) and activated partial thromboplastin times (APTTs), the range of differences between duplicate sample results was analyzed on a widely used automated photo-optical coagulation instrument. Specimens with coagulation test times ranging from normal to threefold above the reference range were included. Of 1,610 PTs and 1,023 APTTs, approximately 95% of duplicates differed by 0.2 s or less and 2.0 s or less, respectively. Approximately 99% of PTs and APTTs differed by 0.4 s or less and 4.0 s or less, respectively; there were three PT and 16 APTT specimens whose duplicates differed by a greater time interval and also by more than 5% of the mean. Thus, PT and APTT testing on automated instrumentation is very precise, but occasional inaccurate single measurements could lead to errors in diagnosis or therapy.

Effects of cod-liver oil on intimal hyperplasia in vein grafts used for arterial bypass.

Cod-liver oil rich in eicosapentaenoic acid, an unsaturated fatty acid, has been shown to inhibit platelet aggregation. To determine the effect of this acid on vein-graft intimal hyperplasia, 46 segments of undistended external jugular vein were interposed between the bilaterally divided femoral arteries of 26 mongrel dogs. The animals received a 2% cholesterol diet for 1 week before and 6 weeks after the operation. Eight control animals received the diet alone, eight received cod-liver oil containing 1.8 g of eicosapentaenoic acid daily, for 1 week before and 6 weeks after operation, and seven animals received 1.8 g of eicosapentaenoic acid daily for 6 weeks after operation. Intimal thickness was measured at 6 weeks with a Zeiss computerized interactive image analysing system from multiple cross-sections of vein graft; 395 +/- 10 measurements were made from each graft. The intima measured 4 +/- 0.2 micron (SEM) before implantation and increased to 83 +/- 10 micron in the controls. Eicosapentaenoic acid administered before and after operation reduced intimal hyperplasia to 24 +/- 2.5 micron (p less than 0.001) and to 30 +/- 5 micron in animals receiving eicosapentaenoic acid after operation only (p less than 0.001). These results indicate that the acid inhibits intimal hyperplasia of canine vein grafts but that it is more effective when given before operation (p less than 0.01).

Cod-liver oil in the prevention of intimal hyperplasia in autogenous vein grafts used for arterial bypass.

Cod-liver oil, rich in eicosapentaenoic acid, an unsaturated fatty acid, was administered to 14 mongrel dogs to determine if this acid would prevent platelet-mediated intimal hyperplasia. Twenty-eight 1 cm segments of undistended jugular vein were interposed between bilaterally divided femoral arteries. Seven control animals were fed a 2% cholesterol diet 1 week before and for 6 weeks after the operation. A further seven animals received cod-liver oil capsules containing 1.8 gm of eicosapentaenoic acid daily 1 week before and for 6 weeks after autogenous vein implantation, in addition to the lipid-supplemented diet. Baseline serum cholesterol was 4.6 +/- 0.4 mmol/L. The rise in serum cholesterol was similar in the two groups and increased to 7.4 +/- 0.6 mmol/L (control group) and to 6.8 +/- 0.2 mmol/L (eicosapentaenoic acid group) (p less than 0.001). Prothrombin time, partial thromboplastin time, bleeding time, and platelet counts were unchanged in the two groups. Vein grafts, harvested at 6 weeks, were fixed in formaldehyde. Mean intimal thickness was measured from multiple vein graft cross sections with a Zeiss computerized interactive image analyzing system. A mean of 140 +/- 11 measurements were computed from each graft. Marked intimal hyperplasia occurred in the control group and increased from 4.3 +/- 0.3 to 86.4 +/- 14 micron. In contrast, a high eicosapentaenoic acid diet inhibited intimal hyperplasia, with intimal thickness only increasing from 4.0 +/- 0.4 to 24.8 +/- 2.7 micron (p less than 0.001). These data indicate that eicosapentaenoic acid inhibits platelet-mediated intimal hyperplasia and suggest that cod-liver oil could be used to prevent intimal hyperplasia in vein grafts used for myocardial revascularization.

Ultrastructure of Candida parapsilosis endocarditis.

We used light microscopy and scanning and transmission electron microscopy to study the structure of Candida parapsilosis vegetations on five surgically removed porcine bioprosthetic valves. Scanning electron microscopy revealed a "mossy" amorphous surface. In some areas, C. parapsilosis cells could be seen below the surface layer. In areas in which the vegetation had cracked, myriads of healthy C. parapsilosis cells were seen to be loosely adherent to one another. These cells were covered with a flocculent or fibrillar matrix. A compact intercellular matrix was evident by transmission electron microscopy. Hyphal elements were seen invading valvular tissue. The loose matrix that bound large clumps of C. parapsilosis cells explains why large emboli are frequent complications of Candida endocarditis.

Acetate and energy metabolism during hemodialysis.

The oxidation of acetate infused in acetate infused in large quantities during acetate dialysis should provide considerable energy for the hemodialysis patient. Previous attempts to measure acetate oxidation rate and thus energy yield by measuring bicarbonate generation rate are flawed because bicarbonate generation occurs by equimolar proton consumption when acetate is activated to acetyl Co-A but before acetyl Co-A has entered the Krebs cycle. Besides the Krebs cycle, acetyl Co-A could enter many other nonoxidative pathways. By using the primed continuous infusion radioisotope (1-14C acetate) dilution technique of Steele, in conjunction with indirect calorimetry, we obtained direct measurements of acetate turnover and immediate oxidation rates and energy yield in 7 stable hemodialysis patients. Commercial dialysate contained glucose (12.4 mmoles/liter), acetate (38 mmoles/liter), plus routine electrolytes. Acetate turnover was 57.2 +/- 2.9 mumoles/min X kg. Of the acetate entering the body, 31.6 +/- 3.8 mumoles/min X kg were immediately oxidized to carbon dioxide and water, which accounted for 54.4 +/- 5.2% of the turnover rate. The amount that entered the blood was 869 mmoles, and 472 mmoles (54.4%) were oxidized; 138 mmoles (15.8%) made up the steady-state pool, and 258 mmoles were directed into nonoxidative pathways (29.7%). During dialysis, 40.3 +/- 4.8% of the carbon dioxide output or metabolic rate was accounted for by acetate oxidation. Thus, acetate emerged as the major contributor to energy production, supplying up to 65% of the total caloric needs during dialysis. The RQ calculated from the lung carbon dioxide excretion was 0.74 +/- 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Endocarditis due to Q fever in Nova Scotia: experience with five patients in 1981-1982.

Q fever endocarditis is rarely reported in North America; only four cases have been documented since 1953. In 1981-1982, five cases were identified in the Victoria General Hospital, Halifax, Nova Scotia. Four patients were from widely separated areas of Nova Scotia and one was from Prince Edward Island. Four patients with long-standing valvular abnormalities, including two with prosthetic valves, presented with recurrent febrile episodes. The fifth patient, who was previously well, had recurrent septic embolic episodes. Clinical features and laboratory findings were variable. Diagnosis by serology was confirmed in four patients by culture of Coxiella burnetii from excised tissue. Histopathology varied from nonspecific inflammatory changes to two more distinctive patterns; electron microscopy showed C burnetii in two patients. Therapy with tetracycline and trimethoprim-sulfamethoxazole was beneficial, although three patients required valve replacement for hemodynamic deterioration. Q fever endocarditis may be more common than is recognized, and serological investigations should be performed in all cases of culture-negative endocarditis.

Localized dystrophic amyloidosis of heart valves.

A survey of 152 surgically resected heart valves (90 aortic, 60 mitral, two pulmonic) from a consecutive series of 142 adult patients revealed congophilic, green birefringent, amyloid deposits in 81 valves (59 aortic, 22 mitral) from 77 patients from 41 to 79 years of age. Amyloid was found in 50 (82 per cent) of 61 valves showing degenerative calcific sclerosis and in 31 (53 per cent) of 58 valves showing post-rheumatic sclerosis but in none of 33 valves showing more acute disease processes (myxoid transformation, "stretch lesions," healed bacterial endocarditis). All the amyloidotic valves showed some calcification, and amyloid deposits frequently occurred around the calcified foci. Histochemically, the valvular amyloid was distinguishable from other major forms of amyloid by its largely negative alcian blue and periodic acid-Schiff staining and by its pepsin-resistant iodine staining. The localized, dystrophic nature and unusual histochemical properties of this valvular amyloidosis clearly distinguish it from other forms of cardiac amyloidosis.

Contribution of dialysate acetate to energy metabolism: metabolic implications.

During hemodialysis large amounts of acetate enter the bloodstream. Generally, it is assumed that this exogenous acetate load is oxidized immediately to carbon dioxide and water; however, the rate of plasma acetate oxidation and the effect of acetate oxidation on energy metabolism during hemodialysis has not been determined previously. The rates of plasma acetate turnover and oxidation were determined during hemodialysis in seven chronic renal failure patients by the primed continuous infusion of [1-14C] acetate. The plasma acetate turnover rate (57.2 +/- 2.9 mumoles/min X kg) agreed closely with the mass transfer rate of dialysate acetate into the bloodstream (55.3 +/- 3.2 mumoles/min X kg). Of the acetate entering the bloodstream, 54.5 +/- 5.2% or 31.6 +/- 3.77 mumoles/min X kg was oxidized immediately accounting for 40.3 +/- 4.8% of the patient's caloric expenditure. Although the oxidation of acetate during dialysis supplied a major portion of the patient's caloric need, a significant quantity of acetate was eliminated by pathways other than direct oxidation. An average overall respiratory quotient (RQ) of 1.0 +/- 0.02 indicated that fat oxidation was spared to maintain energy homeostasis during hemodialysis. The calculated non-protein RQ exceeded unity suggesting that net fat synthesis actually occurred.

An improved histochemical method for distinguishing colonic acetylsialomucin from other epithelial mucins.

A technical modification of the original histochemical methods for distinguishing human colonic acetylsialomucin from other epithelial mucins is described. The modification uses a naphthoic acid hydrazide-diazonium salt sequence in place of the original borohydride or blue Schiff treatments in the first stage of the staining procedure and a more dilute solution of periodic acid in the second stage. By these means, strongly contrasting staining of colonic acetylsialomucins in magenta red and all other mucins in dark blue may be consistently produced.