Repair of full-thickness defects in the femoral trochlea of dogs after trochlear arthroplasty

Trochlear arthroplasty was performed on one stifle in each of 18 Greyhounds; their contralateral pelvic limbs and the pelvic limbs of 2 dogs treated with sham surgery were controls. At 2, 4, 8, and 16 weeks, radiography, glycosaminoglycan histochemical analysis, histologic examination, and scanning electron microscopy of the trochlear surface were done. All dogs used the limb and walked without an observable limp within 2 weeks after surgery. Radiography at euthanasia did not reveal degenerative changes. Well-vascularized, highly cellular, loose fibrous connective tissue was reorganized with time into a dense fibrous connective tissue covering the entire wound. Scanning electron microscopy revealed that the replacement tissue surface was rough, torn, and debris-covered. Differential histologic staining established that change to fibrocartilage had begun deep within the replacement tissue. Histochemical analyses corroborated those observations.

The morphology of the axons and axon collaterals of rat jaw-elevator motoneurones

We have made intracellular injections of horseradish peroxidase into the somata of jaw-elevator motoneurones and subsequently reconstructed the axonal morphology of 4 cells. In each case the axons gave off collaterals which were essentially restricted to the ventral portion of the V motor nucleus. This observation provides the first evidence that these motoneurones may exert recurrent synaptic effects.

Equations for the prediction of resting energy expenditure in chronic obstructive lung disease

Resting energy expenditure can be obtained either by indirect calorimetry or from prediction equations. Several prediction equations were compared to the measured value of REE in a group of COPD patients with moderate to severe disease. Then, using the same group of patients, a new equation was derived by regression analysis and was prospectively tested on patients with similar characteristics. Equations derived from normal populations (Harris-Benedict, Wilmore nomogram) were shown to underestimate REE by 300-400 Kcal. Equations that use body weight as the only variable were found to be easier to use and did not appear to sacrifice accuracy. Quebbeman Ausman body weight, Quebbeman Ausman body surface area and a regression equation derived from COPD patients (males, REE = 11.5 x wt [kg] + 952; females, REE = 14.1 x wt [kg] + 515) performed better than other currently used equations. In both stable COPD and COPD with exacerbation, the mean predicted values fell within a standard deviation (+/- 167 Kcal) of measured values.

1-Ethynyl-4-hydroperoxy-1,2,3,4-tetrahydro-1-naphthol

C12H12O3, Mr = 204.2, monoclinic, P2(1)/c, a = 11.815 (2), b = 7.673 (2), c = 12.580 (3) A, beta = 115.06 (2) degree, V = 1033.1 (9) A3, Z = 4, Dx = 1.313 g cm-3, lambda (Cu K alpha) = 1.54184 A, mu = 7.34 cm-1, F(000) = 432, T = 299 K, R = 0.065 for 1420 observations (of 2131 unique data). The stereochemistry of the hydroxyl and hydroperoxyl groups is cis. The hydroperoxyl O-O bond distance is 1.476 (2) A. The hydrogen-bonding pattern consists of two intermolecular interactions: a hydroperoxyl donor to the hydroxyl group, with an O...O distance of 2.818 (2) A and an O-H...O angle of 168 (2) degree, and a hydroxyl donor to O(3) of the hydroperoxyl group, with a distance and angle of 2.670 (2) A and 170 (2) degree, respectively.

Carcinogen testing. Fact and fallacy

In the absence of human information on the carcinogenicity of chemical substances, one must rely primarily on information from long-term animal testing. Although far from perfect, animal studies seem to be reasonable predictors of the human experience, both qualitatively and quantitatively. Short-term tests for genotoxicity may be helpful for establishing priorities for chemical testing, but they are not as strong indicators of potential carcinogenicity as had been previously thought. New directions in toxicologic research hold the promise for scientists being able to perform more reasoned assessments of carcinogenic risk.

Equivalent potency and pharmacokinetics of recombinant human growth hormones with or without an N-terminal methionine

Two forms of human GH (hGH) have been produced by recombinant DNA technology. One form has an amino acid sequence identical to that of the natural pituitary hormone (rhGH) and the other form has an additional N-terminal methionine (Met-hGH). The biological potencies of these 2 polypeptides have been compared in hypophysectomized rats in a multidose study measuring body weights and several long bone growth parameters. The pharmacokinetic profiles after iv and sc injection were determined in cynomolgus monkeys in a 4-period cross-over study. All of the measured parameters in all the studies indicated that there was no difference in the two forms of hGH. Measurements taken after 27 daily injections of rhGH or Met-hGH (30-500 micrograms/kg.day) indicated that femur length and width of the proliferative zone in the tibial epiphysis showed dose-related effects for both forms of hGH but no difference between them. The relative potency, based on body weight gain, was calculated using a parallel line bioassay. Weight gain after 8 daily injections in the 5-dose long bone growth study indicated a rhGH potency of 0.80 (95% confidence interval, 0.5-1.23) relative to Met-hGH. It was concluded that the presence of an N-terminal methionine on hGH has no effect on potency in this model. The pharmacokinetic parameters after iv administration were estimated by fitting serum concentration-time data to a 2-compartment model. Parameters after sc injection were computed by compartment-independent methods. Met-hGH and rhGH had very similar pharmacokinetic profiles after both routes of administration. Comparison of the pharmacokinetic parameters indicated that the clearance after iv administration (rhGH, 15 ml/min; Met-hGH, 13 ml/min) and the sc bioavailability (rhGH, 0.72 +/- 0.21; Met-hGH, 0.59 +/- 0.21) were not significantly different for the 2 forms of hGH. It was concluded that rhGH and Met-hGH have equivalent bioavailability and pharmacokinetics in cynomolgus monkeys.

Pharmacokinetics and tissue distribution of recombinant human tumor necrosis factor-alpha in mice

The serum pharmacokinetics and the major organs of accumulation of recombinant human tumor necrosis factor-alpha (rHuTNF) were determined in BDF1 mice after intravenous and intramuscular administration. Serum concentrations of immunoreactive protein were determined by enzyme-linked immunosorbent assay, and radioactivity was quantitated by beta and gamma scintigraphy. The serum pharmacokinetics of labeled and unlabeled rHuTNF were identical when administered by the intravenous route. After intravenous doses of 165 to 320 micrograms/kg, the clearance was 2.9-3.6 ml/hr, the initial volume of distribution was 1.4-1.6 ml (70-80 ml/kg), and the half-life was 18.5-19.2 min. Intramuscular administration of 320 micrograms/kg resulted in a peak serum concentration of 112 ng/ml. The time of the peak concentration was 1 hr, and the bioavailability of the intramuscular dose was 12%. The data suggest that the disposition of this protein may be biexponential. If this is the case, the terminal phase would appear to account for less than 1% of the total AUC. Since serum concentrations in the terminal phase are at the sensitivity limit of the assay, a single half-life is reported. 125I-Labeled and metabolically labeled 3H-rHuTNF were used to examine tissue distribution. After intravenous 125I-rHuTNF administration, the rank order of accumulation of the 125I-radiolabel in the major organs (per cent dose per organ over 1440 min) was: liver greater than kidney greater than lung greater than heart greater than spleen. This rank order of accumulation was confirmed by intravenous 3H-rHuTNF administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary pulmonary adenocarcinoma with brain stem metastasis in a dog

Primary pulmonary adenocarcinoma with metastatic spread to the brain stem was diagnosed at necropsy in an aged Bulldog. Initial clinical signs included coughing, decreased exercise tolerance, and personality changes. Primary differential diagnoses after thoracic radiography were multicentric metastatic neoplasia or fungal disease. Later clinical signs (inappetence, unilateral facial paralysis and decreased sensation, and hemiparesis) were referable to the effect of the tumor on cranial nerves V and VII and other brain stem structures. Primary lung tumors are uncommon, as are metastatic tumors within the CNS. Radiographic appearance alone of lung lesions is insufficient for accurate diagnosis.

Resistance of capuchin monkeys to reinfection with Schistosoma haematobium

Capuchin monkeys were resistant to reinfection with Schistosoma haematobium one year after exposure to 500 cercariae, but worms in these monkeys continued to produce normal numbers of eggs. Monkeys were apparently completely refractory to reinfection when challenged 2-5 years after an initial exposure of 1000 to 2000 cercariae.

Pathology of Schistosoma haematobium infection in the capuchin monkey (Cebus apella)

Capuchin monkeys exposed to 500-2000 Schistosoma haematobium cercariae were followed for up to 6 1/2 years after infection. Worm burdens decreased as infections became more chronic and decreasing numbers of eggs and active circumoval lesions were found in the bladder and elsewhere. Nodular and hyperplastic epithelial lesions of the urinary bladder were not seen during the first year of infection but occurred in 30% of monkeys examined 1-2 years after infection and in 23% of those examined between the second and third years; they were present in only 3% of monkeys studied 3-6 1/2 years after infection. These epithelial proliferative lesions were located near foci of egg deposition and occurred in the monkeys with the most intense active lesions in the bladder. The lesions regressed in animals followed sequentially. The lesions thus appear not to be neoplastic. Obstructive lesions of the ureter accompanied by hydronephrosis were present in a few animals. The obstructive uropathy did not appear to cause significant morbidity. Mortality was substantial among infected monkeys at most intervals after infection but was rare among uninfected controls.

Regional changes in myocyte size and number in propranolol-treated hyperthyroid rats

The effects of beta-adrenergic blockade and hyperthyroidism on cardiac myocyte structure was examined. Isolated myocytes were prepared from controls and rats treated for 10 weeks with desiccated thyroid hormone (T), propranolol, and desiccated thyroid hormone plus propranolol (TP). Cells were collected from the right and left ventricle. Cell volume was measured with a Coulter Channelyzer system. Cell length was measured directly using a phase microscope. Myocyte cross-sectional area was calculated from cell volume/length. In addition, hearts from animals in each group were perfusion-fixed and myocyte volume percent was determined morphometrically from tissue sections. The number of right and left ventricular myocytes was calculated using data from isolated cells and whole-sectioned tissue. Propranolol normalized heart rate in hyperthyroid rats. Heart weight to body weight ratios were elevated to a similar extent in both T and TP groups. Compared with controls, myocyte volume was increased (p less than 0.01) in each region of T and TP. Right ventricles had a greater degree of myocyte hypertrophy than left ventricles in both rat groups treated with thyroid hormones. Cell length was increased (p less than 0.01) in T and TP. Most of the myocyte hypertrophy, however, was due to an increase in cross-sectional area. Although volume was unchanged with propranolol treatment alone, myocytes from each region had an increase in length (p less than 0.01) and a reduction in cross-sectional area (N.S.). Myocyte number was slightly reduced in each treatment group, but changes were not statistically significant. In conclusion, thyroid hormones stimulate myocyte hypertrophy by increasing both length and cross-sectional area. Propranolol modifies myocyte dimensions in both euthyroid and hyperthyroid rats, but does not prevent thyroid hormone induced cardiac hypertrophy.

Jarisch-Herxheimer reaction in Lyme disease

The Jarisch-Herxheimer reaction includes the accentuation of symptoms during antibiotic therapy. More commonly associated with the treatment of syphilis, it can also occur in patients treated for Lyme disease caused by the spirochete Borrelia burgdorferi.

The effect on healing of the application of citric acid during replaced flap surgery

The aim of this double-blind controlled clinical trial was to assess the effect on healing following conditioning the root surface with citric acid during replaced flap surgery. Healing was assessed in 18 pairs of sites in 12 patients before surgery and after 3 months; healing was also assessed in 13 pairs of these sites in 10 of the patients after 9 months. During surgery, the root surface at 1 site from each pair was treated with citric acid pH 0.6 for 3 min and the contralateral site was exposed to sterile saline. Healing was assessed by measuring attachment levels, probing depths and recession; in addition, gingival crevicular fluid flow was measured, as was the degree of bleeding on probing. The mean gain of attachment (mm) in the acid and control groups were 1.0 and 1.2, respectively, at 3 months and 1.1 and 0.9 respectively, at 9 months. The results of this study indicate, both clinically and statistically, that the difference in healing between the acid and the non-acid sites is not significant. Thus no additional benefit is shown by using citric acid in conjunction with replaced flap surgery on anterior teeth.

Recurrent cavitary nodules secondary to Hodgkin's disease

A patient with nodular sclerosing Hodgkin's disease had at least three episodes of lung involvement consisting of an infiltrate on one occasion and multiple cavitating nodules on the other two. The cytologic and histologic studies of the lung specimens disclosed the presence of Reed-Sternberg cells on each occasion without any evidence for infection. This represents the first time in which recurrent cavitating nodules have been reported with Hodgkin's disease.

The properties of recombinant chicken growth hormone and its effects on growth, body composition, feed efficiency, and other factors in broiler chickens

Recombinant chicken GH (rcGH) was produced and characterized. Comparison of protein sequence, amino acid composition, mol wt, purity, and immunocross-reactivity showed that except for the N-terminal methionyl group arising from the bacterial expression system, the recombinant and pituitary-derived cGHs were identical. When tested in a hypophysectomized rat growth assay, the recombinant and pituitary materials had the same specific bioactivity. Within 60 min after sc injection of rcGH (480-960 micrograms/kg) in chickens, plasma GH levels increased 4- to 6-fold and remained significantly elevated for at least 5 h. Thrice-daily injections from age 2-24 days had little effect on growth or feed consumption in either male or female broiler chicks. Plasma levels of insulin and triglycerides were significantly elevated by rcGH in 24-day-old females, but not in males. Injection of rcGH counteracted a reduction of tibia length observed in saline-injected controls. The rcGH had no effect on carcass protein, ash content, or nitrogen retention. It is important to note that exogenous GH can be a productivity-enhancing factor in other commercially important species. Administration of bovine GH to cows has been shown to induce a significant increase in milk production (28). This study shows that administration of rcGH to chickens can lead to some significant metabolic effects. However, it is the conclusion of this report that the level of circulating GH is not the limiting factor in the growth of this highly selected species.

Problems facing the decision-maker in the risk assessment process

This paper presents an overview of the U.S. Environmental Protection Agency's risk assessment process, describes problems that the Agency faces in conducting risk assessment, in general, and identifies some specific problems that the Agency confronts when conducting risk assessments on suspected developmental toxicants. As noted by the NAS (National Research Council: "Risk Assessment in the Federal Government: Managing the Process." Washington, DC: National Academy Press, 1983, pp 17-83), improving the quality and comprehensiveness of knowledge is the most effective way to improve risk assessment, but some limitations are inherent and may remain unresolvable. Therefore, inferences will always be required. The Agency's challenge is to ensure that these inferences are as soundly based as possible.

Effects of whole cottonseed, cottonseed oil or animal fat on digestibility of wheat straw diets by steers

Two completely random digestion trials were conducted, each with 12 beef steers (325 kg initial weight), to measure changes in digestibilities of fat and of forage components when fat was added to diets containing 62 to 76% wheat straw. Trial 1 diets contained either no added fat or 6.3% added fat from whole cottonseed (30% of the diet), cottonseed oil or animal fat; diets were formulated to contain equal levels of cottonseed hulls and cottonseed meal. Trial 2 diets contained 0, 2, 4 or 8% added animal fat. In all forms and at all levels, added fat increased apparent digestibility of dietary lipid (P less than .05). However, estimated true digestibility of lipid decreased (from 94 to 71%) as added fat was increased from 0 to 8% (P less than .05). Up to 6.3% added fat increased digestible energy (DE) content of the diet. Fat additions of 2 and 4% increased daily DE intake (P less than .05) and did not depress digestibility of diet components (P greater than .05). Fat additions of 6.3% or greater, either as free fats or as whole cottonseed, reduced (P less than .05) mean acid detergent fiber digestibility from 40 to 28%. In addition to depressing fiber digestibility, 8% added fat reduced (P less than .05) digestibilities of dry matter (from 54 to 47%), organic matter (60 to 52%) and gross energy (60 to 51%). Oil fed as whole cottonseed caused digestibility depressions similar to free fat addition at the same level.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional differences in myocyte size in normal rat heart

Three independent methods were evaluated in an effort to obtain reliable values for myocyte size in adult Sprague-Dawley rats. Cell volume was determined from isolated myocytes by a Coulter Channelyzer system. Cell volume was also determined from the product of length and cross-sectional area of isolated myocytes. Additionally, myocyte cross-sectional area was measured morphometrically from electron micrographs of whole perfusion-fixed tissue. A major goal was to determine if anatomical methods used to measure cell volume produce values comparable to the more expeditious and objective Coulter Channelyzer method. The results of these experiments showed that myocyte dimensions obtained from all three techniques were similar. The second major objective was to use the above-mentioned techniques to evaluate regional differences in myocyte size. Myocyte cross-sectional area and volume were significantly larger in the endomyocardium than in the epimyocardium of the left ventricle. Right ventricle myocytes had significantly smaller volumes and cross-sectional areas than did left ventricle myocytes. There were no regional differences in cell lengths. We conclude that the Coulter Channelyzer system gives values for isolated myocyte volume that are similar to values obtained with histometric techniques; values for isolated myocyte cross-sectional area were representative of values obtained from myocytes in whole-sectioned tissue; significant regional differences in myocyte size are present in adult rat hearts; and regional variations in myocyte size are due to differences in myocyte cross-sectional area rather than cell length.

Simulation: an evolving methodology for health administration education

Simulation provides a valuable addition to a university's teaching methods. Computer-assisted gaming is especially effective in teaching advanced business strategy and corporate policy when the nature and complexity of the simulation permit. The potential for using simulation techniques in postgraduate professional education and in managerial self-assessment appears to be significant over the next several years.

Becker's melanosis and hypoplasia of the breast and pectoralis major muscle

Becker's melanosis can be associated with hypoplastic abnormalities. In our patient (the first case report), it occurred in association with an absent pectoralis major muscle. Although more common in males, this patient demonstrates that Becker's melanosis can occur in females and may be congenital.

Marginal distortion of cast restorations induced by cementation

Eleven full veneer crowns were directly constructed on brass stylized dies. Crown marginal openings and vertical heights were measured before and after cementation with zinc phosphate cement. The following results were established. The marginal opening of complete veneer gold crowns increased during cementation. The vertical heights of well fitting crowns also increased significantly after cementation.

Failure of propranolol to prevent chronic hyperthyroid induced cardiac hypertrophy and multifocal cellular necrosis in the rat

The effect of excess thyroid and thyroid plus propranolol on right and left ventricular structure was examined. Perfusion fixed hearts from untreated adults and those treated for 10 weeks with thyroid, propranolol, and thyroid plus propranolol were embedded in plastic and sectioned for light and electron microscopy. Hyperthyroidism stimulated a significant increase in heart rate, oxygen consumption, and systolic blood pressure. Propranolol was effective in normalizing the heart rate of hyperthyroid rats, but did not affect oxygen consumption or blood pressure. Both left and right ventricular weight increased similarly in thyroid and thyroid-propranolol treated animals, but right ventricular mass increased more than left ventricular mass in both groups. The majority (21 of 24) of right ventricles from thyroid and thyroid-propranolol treated animals had multifocal areas of histologically detected fibrosis. Left ventricular fibrosis was absent or minimal in both hyperthyroid groups. Neither left nor right ventricular fibrosis was observed in control or propranolol only treated animals. We conclude that beta adrenergic stimulation is unnecessary for thyroid induced cardiomegaly, and excess thyroid hormones induce right ventricular fibrosis which is not prevented by propranolol.

Interferon reduces hepatic drug metabolism in vivo in mice

The effects of two highly purified human leukocyte interferons (IFN-A and IFN-AD) on drug-metabolizing capacity in mice have been investigated. IFN-AD was found to produce significant changes in antipyrine half-life, assessed by analysis of 14CO2 exhalation rates following 14C-antipyrine administration. By contrast, IFN-A, which has considerably less antiviral potency than IFN-AD, was found to have no effect on antipyrine half-life. The administration regimen was found to markedly alter the effects seen with IFN-AD. When IFN-AD was given as single daily doses (5 X 10(7) units/kg/day X 3 days), the half-life of antipyrine increased by a mean of 40% (from 21.0 to 28.9 min). However, when a smaller daily dose (3 X 10(7) units/kg/day) was given as a continuous infusion, the antipyrine half-life increased by more than 3-fold (from 20.8 to 68.5 min) after 3 days of administration. Continued infusion for a further 3 days produced no additional change in antipyrine half-life. These results demonstrate that human leukocyte interferons can significantly inhibit hepatic metabolic activity in vivo.