Birth intervals and perinatal health: an investigation of three hypotheses

This analysis uses data from Hungary, Sweden and the United States to investigate the factors contributing to the high health risks observed among infants born within 12 months of the preceding birth. Three hypotheses for poor perinatal health are explored: confounding by prematurity, selection of high-risk mothers into short birth intervals and maternal depletion. Results show that prematurity accounts for the greatest share of the excess risks associated with closely spaced births, and for virtually all of the excess risk of late fetal death. After the confounding effects of prematurity are controlled for, the study finds that infants conceived within a few months of the preceding birth remain at higher-than-average risk of low birth weight, preterm birth and neonatal death. The results suggest that avoidance of birth intervals of less than two years could be expected to effect a 5-10 percent decreased risk of low birth weight and neonatal death.

Effect of dietary biotin supplementation on sow reproductive performance and soundness and pig growth and mortality

A 3-yr study was conducted to evaluate the effect of dietary biotin supplementation on the reproductive performance of 90 sows and gilts, and on the pre-weaning growth and mortality of 223 litters. Corn-soybean meal-based diets supplemented with either 0 or 440 micrograms/kg d-biotin were fed to sows throughout their reproductive cycle. Biotin supplementation had no beneficial effect (P greater than .10) on 107-d sow weight, sow weight at weaning, weaning to estrus interval, foot lesion score, hair loss score, structural soundness score, number of pigs born, number and percentage of pigs born alive or number and percentage of pigs alive at 21 d of age. Biotin supplementation had no effect (P greater than .10) on pig growth or mortality to 21 d of age. These data do not support the concept that biotin supplementation of sow diets is needed.

The effect of stem stiffness on femoral bone resorption after canine porous-coated total hip arthroplasty

Bilateral noncemented total hip arthroplasty (THA) was produced in dogs to determine the effect of stem stiffness on stress-related bone resorption. Two porous-coated femoral implants of substantially different stiffnesses were designed for direct comparison. One was manufactured from cobalt-chromium (CoCr) alloy, the other from titanium alloy. The titanium stem was hollowed out to a wall thickness of 1 mm to further reduce its stiffness. The cumulative stiffness differences were about 5.4-fold axially and 3.6-fold in bending and torsion. Staged bilateral THA was performed on eight dogs. Each dog received a stiff CoCr stem on one side and a flexible titanium stem on the other. After death, the femora were removed and processed for undecalcified thin-section histology. Bone ingrowth and remodeling were quantified by computer-aided image analysis and compared between stem designs. All femoral specimens showed bone ingrowth fixation of both stiff and flexible stems along the implant length. Tetracycline labeling indicated active bone turnover in the femoral cortex and in regions of ingrowth. However, gross differences in femoral bone remodeling were observed both roentgenographically and histologically. Femora with the flexible stems consistently showed much less bone resorption than those with the stiff stems. Quantitative analysis of paired cross-sections indicated an average of 25%-35% more cortical bone area in the femora with flexible stems. Severe resorption of the cortex in the midstem region occurred in three of the femora with the stiff stems but in none with the flexible stems. Stem stiffness strongly influences bone remodeling. The flexible stem results in more uniform load transfer and less stress shielding.

Modeling the effects of ozone on soybean growth and yield

A simple mechanistic model was developed based on an existing growth model in order to address the mechanisms of the effects of ozone on growth and yield of soybean [Glycine max. (L.) Merr. 'Davis'] and interacting effects of other environmental stresses. The model simulates daily growth of soybean plants using environmental data including shortwave radiation, temperature, precipitation, irrigation and ozone concentration. Leaf growth, dry matter accumulation, water budget, nitrogen input and seed growth linked to senescence and abscission of leaves are described in the model. The effects of ozone are modeled as reduced photosynthate production and accelerated senescence. The model was applied to the open-top chamber experiments in which soybean plants were exposed to ozone under two levels of soil moisture regimes. After calibrating the model to the growth data and seed yield, goodness-of-fit of the model was tested. The model fitted well for top dry weight in the vegetative growth phase and also at maturity. The effect of ozone on seen yield was also described satisfactorily by the model. The simulation showed apparent interaction between the effect of ozone and soil moisture stress on the seed yield. The model revealed that further work is needed concerning the effect of ozone on the senescence process and the consequences of alteration of canopy microclimate by the open-top chambers.

Enhanced survival of full-thickness skin grafts following the application of DC electrical fields

The present study was undertaken to determine if uses of exogenous electrical fields could improve the posttraumatic quality of dermis and epidermis in isolated grafts in the rat. In blinded procedures, a full-thickness area of skin was removed and reattached to the original site. A galvanic device delivering 4.5 microA of direct current was applied using three electrode orientations: (1) anode above graft (AT; N = 8), (2) cathode above graft (CT; N = 7), and (3) no current (NC; N = 7). Current delivery was discontinued 4 days postoperatively. Quantitative assessment at 7 days postoperatively indicated the presence of necrotic skin over 80 to 90 percent of the graft surface area in NC and CT animals. In contrast, only 50 percent of the graft area was necrotic in AT rats. Histologic examinations indicated a significantly thickened dermis in the AT (versus NC and CT) rats, accompanied by patches of multilayered intact epidermis, which was virtually absent from the other experimental groups. Results are consistent with the hypothesis that direct-current stimulation can affect skin graft survival and repair.

The role of lymphocytes and monocytes in hematopoietic growth factor production by peripheral blood mononuclear cells

Stimulated peripheral blood mononuclear cells (MNC) are one of the richest described physiologic sources of colony-stimulating activity. To understand the molecular basis for, and the cellular sources of, this MNC activity, we cultured purified human lymphocytes and monocytes for 2 hr to 6 days and examined colony-stimulating factor (CSF) gene activity by Northern blot analysis. We show that MNC are capable of expressing messenger RNA for macrophage (M)-CSF, granulocyte (G)-CSF, GM-CSF, and multi-CSF when stimulated with mitogens. The time courses of induction of these genes differ, with G-CSF induction preceding that of the other CSFs. In addition, the spectra of CSFs produced by cell populations enriched for lymphocytes, monocytes, or macrophages differ. The implications of these findings for the selective activation of hematopoiesis are discussed.

Carcinoma of the esophagus: a comparison of the results of transhiatal versus transthoracic resection

The cases of 78 patients with primary esophageal carcinoma treated from 1977 to mid-1987 were retrospectively analyzed. Fifty-two of the patients underwent transthoracic esophagogastrectomy (TTE) and 26, transhiatal esophagectomy (THE). The two groups were statistically similar in preoperative characteristics except that more of the THE group had received chemotherapy; this group had relatively more tumors of the upper esophagus; and 20 (77%) of the THE group, compared with 50 (96%) of the TTE group, had tumors in stages III and IV. The incidence of major postoperative complications did not differ significantly between the two groups. There were five (19%) anastomotic leaks in the THE group, but only one led to a prolongation of hospital stay by more than 14 days, whereas all three (6%) of the leaks in the TTE group caused hospital stay to be prolonged several weeks. Overall morbidity was high: 75% (39/52) for the TTE patients and 85% (22/26) for the THE patients (p greater than 0.10). Hospital mortality was 6% (3/52) in the TTE group and 8% (2/26) in the THE patients (p greater than 0.10). There was no significant difference in actuarial survival either between the two groups as a whole or between those patients in each group who had stage III or IV tumors. We conclude that THE, among the types of patients for whom we used the procedure, provides long-term survival comparable with that provided by TTE without causing a significant increase in hospital mortality or morbidity.(ABSTRACT TRUNCATED AT 250 WORDS)

Determinants of intrauterine growth retardation: evidence against maternal depletion

This analysis examines the relationship between length of preceding birth interval and risk of intrauterine growth retardation using data on Swedish infants from the 1973 World Health Organization study of perinatal mortality. Results of a multivariate logit analysis demonstrate that the lower than average mean birth weight of infants born after short birth intervals cannot be completely attributed to their shorter mean gestation length. Infants born after birth intervals of 12 months or less are 30% more likely to be small for gestational age (SGA) than infants born 18-59 months after the previous birth, even when the effects of maternal age and parity are controlled. The results obtained here do not support maternal depletion as an explanation for the association between short birth intervals and elevated risk of SGA, since there is no evidence of an attenuation of the risk of SGA with increasing length of interval in the under 18 month birth interval range.

Suppression of in vitro granulocytopoiesis by captopril and penicillamine

The mechanisms underlying drug-induced neutropenia are poorly characterized. We have examined the mechanism of suppression of granulocytopoiesis by captopril and penicillamine using human and canine bone marrow cells in an in vitro culture system. Addition of captopril caused no significant change in granulocyte-macrophage colony formation at concentrations up to 30 micrograms/ml. In the presence of CuSO4 (1-3 micrograms/ml), however, captopril caused significant inhibition of colony growth (p less than 0.05). Penicillamine, another agent associated with neutropenia and, like captopril, having a reactive thiol group, also inhibited colony formation in the presence of copper. Chemical congeners of captopril lacking a reactive thiol group and enalaprilic acid, an alternative angiotensin-converting enzyme (ACE) inhibitor, failed to show inhibition, suggesting that the thiol group and not ACE inhibition was responsible. Analysis of day-7 colonies (98% neutrophilic) and day-21 colonies (37% neutrophilic, 30% macrophagic, 27% eosinophilic, and 6% mixed) showed that neutrophil-containing colonies, but not nonneutrophilic colonies were inhibited by the addition of captopril plus copper. Catalase totally reversed the inhibition of colony formation caused by these agents. Direct measurement of oxygen consumption in the presence of captopril showed marked enhancement with the addition of CuSO4 and a 48% reduction in the presence of added catalase. These data indicate that drugs with a reactive thiol group can interact with copper to generate H2O2, which can be toxic to neutrophilic progenitor cells. We postulate that this may be an important mechanism for drug-associated neutropenia and a general mechanism for drug-induced marrow cell injury.

Efficacy of oxfendazole against inhibited larvae of Ostertagia ostertagi acquired by calves in the spring

During the spring of 1985, 40 calves grazed pastures known to have high numbers of spring inhibition-prone, infective Ostertagia ostertagi larvae. Calves were removed from pasture and placed in outdoor pens with concrete floors from 10 days prior to treatment until necropsy 14 days after treatment. Ten calves were allocated to each of 4 treatment groups, and oxfendazole was administered to each group by intraruminal injection at dosages of 0, 2.25, 4.5, and 6.75 mg/kg of body weight. Efficacies greater than or equal to 94.6% were achieved at dosages of 4.5 and 6.75 mg/kg against adult Ostertagia spp, Trichostrongylus spp, Haemonchus placei, Cooperia punctata, Bunostomum phlebotomum, Oesophagostomum radiatum, and Dictyocaulus viviparus. Efficacy against inhibited larvae of O ostertagi was variable, with the highest efficacy (90.2%) attained at a dosage of 6.75 mg/kg.

Surgical management of lung cancer with solitary cerebral metastasis

Between 1964 and 1986, 19 patients underwent resection of both a primary lung cancer and the associated brain metastasis. One patient underwent resection of 2 separate primary lung cancers and the associated metastases. The 12 men and 7 women ranged in age from 42 to 67 years (mean, 54.6 years). The cell type was adenocarcinoma in 12 tumors, squamous or adenosquamous cell in 5, large cell undifferentiated or anaplastic in 2, and malignant carcinoid in 1 tumor. The types of resection were as follows: lobectomy for 12 neoplasms, pneumonectomy for 5, bilobectomy for 2, and wedge resection for 1 neoplasm. Radiotherapy to the brain was given in connection with sixteen of the twenty craniotomies. The patient with 2 separate primary neoplasms survived 19 years before dying 5 months after the second craniotomy. The mean survival is 8.0 +/- 2.1 years (+/- the standard error), and the median survival is 1.67 years. Survival at 1 year was 65 +/- 10.7% and at 5 years, 45 +/- 11.1%. On univariate analysis, the following factors were found to correlate significantly with longer survival: a lung tumor in Stage I or II; negative mediastinal nodes; curative rather than palliative resection of the lung tumor; and age younger than 55 years. However, on multivariate analysis, only curative resection was a significant factor (p less than 0.01). We believe these results justify continued application of this combined surgical approach to patients having limited-stage lung cancer with a solitary brain metastasis.

Abnormal GM-CSA generation by lymphocytes in patients with cyclic hematopoiesis

Human cyclic hematopoiesis (CH) is a disease characterized by regular 21-day cyclic fluctuations of blood cell counts due to fluctuations in bone marrow cell production. The regular periodicity of the fluctuations suggests a defect in a regulatory feedback control loop. We examined the production of monocyte-derived recruiting activity (MRA) by monocytes and the response to MRA of lymphocytes from three patients with CH. MRA production was normal or increased in patients' monocytes, but granulocyte-macrophage colony-stimulating activity (GM-CSA) production in response to MRA was decreased in lymphocytes from patients with CH (p = 0.005). These data suggest that the regulatory defect in CH may involve defective lymphocyte generation of GM-CSA, resulting in deficient production of mature neutrophils.

Experimental inhibition of reactive gliotic-like changes in astrocytic cultures

Dibutylcyclic AMP (DiBucAMP) can induce astroblast-containing cultures to form cells which resemble reactive astrocytes observed in vivo. In the present study, myelin- or axolemmal-enriched fractions were assessed for the ability to inhibit (DiBucAMP)-stimulated reactive-like changes in astrocytic cultures. Addition of exogenous myelin- or axolemmal-enriched fractions to DiBcAMP-exposed cultures prevented drug-induced elevation of lactic dehydrogenase (LDH) 2 days after initial addition of the drug and moderated DiBucAMP-induced decreases in the enzyme's activity normally observed 5 days later. The proportion of reactive colonies (i.e., those in which more than 50% of cells are stellate-shape) was significantly lower in cultures exposed to the drug plus myelin or axolemma vs those exposed to DiBucAMP alone. The inhibitory factors in axolemmal fractions were heat sensitive (at 100 degrees C), whereas those in myelin were not. Both fractions were inactivated by trypsin. Whole brain homogenates had no effect on diBucAMP-stimulated changes in culture.

Efficacy of levamisole and netobimin against Haemonchus contortus in lambs in Louisiana

Efficacy of levamisole was evaluated in a suspected levamisole-resistant population of Haemonchus contortus in the Louisiana State University sheep flock. The efficacy of netobimin also was evaluated against this population of Haemonchus. In trial 1, 5 lambs naturally infected with H contortus were given 8 mg of levamisole/kg of body weight as a drench, and 5 lambs were not treated (controls). Nematode recovery after slaughter indicated 0% efficacy against H contortus. In trial 2, 30 nematode-free lambs were each given 8,300 F1 generation infective larvae of H contortus, which were derived from parent H contortus that survived 2 levamisole treatments in lambs being maintained in a nematode-free environment. Ten lambs were treated with 8 mg of levamisole/kg as a drench, 10 were treated with 20 mg of netobimin/kg as a drench, and 10 were not treated (control). Nematode recovery after slaughter revealed 62.3% and 99.8% efficacy for levamisole and netobimin, respectively, against H contortus.

Transhiatal esophagectomy for carcinoma of the esophagus: experience with 26 patients

Transhiatal esophagectomy was performed in 26 patients with esophageal carcinoma. The patients were selected for this procedure by means of transhiatal palpation of the tumor at laparotomy. Twenty had squamous cell carcinoma and 6, adenocarcinoma. The tumor locations were the upper third in 8, middle third in 12, and lower third in 6. On postoperative staging, 15 patients had Stage III and 6, Stage IV neoplasms. Among 25 elective resections there was 1 hospital death, which was due to severe coronary artery disease. One patient who had an urgent resection for a perforated carcinoma died of multisystem failure 32 days postoperatively. Complications included splenic injury requiring splenectomy in 5 patients; tracheal laceration in 2 patients (only 1 requiring a thoracotomy); azygos vein laceration requiring sternotomy for repair in 1 patient; chylothorax in 1; recurrent laryngeal nerve paralysis in 3 (temporary in 2); and transient anastomotic leaks in 3. Five patients had pneumonia with transient respiratory failure. Twelve of the operative survivors died of cancer 3.2 to 32 months postoperatively, and 12 are alive 3 to 28 months after operation. The actuarial survival is 53 +/- 11% (+/- standard error) at one year and 46 +/- 12% at two years. Transhiatal esophagectomy is a reasonable, safe operation that should be considered for tumors at all levels of the esophagus.

Microscopic metastasis of a human lung carcinoma cell line in athymic nude mice: isolation of a metastatic variant

A human lung carcinoma cell line, UCP3, was carried as subcutaneous xenotransplants in athymic mice. Autopsies of these animals showed rare foci of microscopically visible metastases to any of the other organs. A metastatic variant, 522, was established serendipitously in vitro as a continuous cell line by blind isolation of the pulmonary metastatic foci, at the time of autopsy, from the lungs of the animals that carried subcutaneous xenotransplants of the parental cell line. The parental UCP3 and the metastatic variant 522 were examined by karyotypic and isoenzyme analysis and shown to be human and related. The metastatic variant, 522, metastasizes spontaneously from subcutaneous sites (like the parental UCP3). However, it forms larger subcutaneous xenotransplants and forms more metastatic foci in the lungs of the animals than does the parental cell line. Comparisons of the cell surface glycolipids show many similarities and a few differences. This model system may now be used for further investigations into the processes of metastasis of this human neoplasm.

Cross-union complicating fracture of the forearm. Part II: Children

Cross-union is a rare complication of fractures of the forearm in children. Of the ten cross-unions reported in this series, four were Type 2 (middle third or non-articular part of the distal third of the radius and ulna) and six were Type 3 (proximal third of the forearm). There were no Type-1 (intra-articular part of the distal third of the radius and ulna) cross-unions. As in adults, the Type-2 cross-unions followed a high-energy injury. Three of the four Type-2 cross-unions were excised; one of them recurred. Type-3 cross-unions occurred equally after closed or open reduction of a fracture. Three patients with a Type-3 cross-union had excision of the radial head. The only patient who did not have a recurrence of the cross-union also underwent insertion of a prosthesis for the radial head. The results after resection of a cross-union appear to be better in the adult than in the child, although the number of patients in this and other studies is too small to allow firm conclusions.

Cross-union complicating fracture of the forearm. Part I: Adults

The cases of twenty-eight adults who had cross-union as a complication of fractures of the forearm were analyzed according to a new classification system. Four cross-unions were Type 1 (distal intra-articular part of the radius and ulna); fourteen, Type 2 (middle third or non-articular part of the distal third of the radius and ulna); and ten, Type 3 (proximal third of the radius and ulna). Type-1 cross-union occurred rarely, but it developed most commonly after closed reduction of a fracture. Types 2 and 3 typically followed severe local trauma and delayed open reduction. Bone fragments left in the interosseous space and bone screws that broached the opposite part of the cortex were common findings. Seventeen cross-unions were excised. Three of the four Type-1, none of the ten Type-2, and two of three Type-3 cross-unions recurred. The results after excision of Type-2 cross-unions in our series were far better than other results that have been previously reported.

Effects of a low-fat, low-cholesterol diet on serum lipids, platelet aggregation and thromboxane formation

The purpose of this study was to test the effects of a low-fat, low-cholesterol diet on serum lipids, platelet aggregation, thromboxane formation and blood pressure. Fifteen hyperlipidemic males with normal blood pressure were treated for 2 weeks. Resting supine blood pressure, total serum cholesterol, HDL-cholesterol, the ratio of total cholesterol/HDL-cholesterol and triglycerides all were significantly reduced. The maximum aggregation and velocity of aggregation for isolated platelets stimulated with either ADP or collagen was significantly reduced. Thromboxane formation during 5 min of platelet aggregation with collagen or ADP was also significantly reduced. These results have important implications for hypertension and atherosclerotic cardiovascular disease.

Pulmonary function in dogs with mitral valve regurgitation

Mitral valve regurgitation was created in 2 groups of dogs. Groups were selected on absence (group 1) or presence (group 2) of clinical signs of congestive left ventricular failure. Group-2 dogs, in which mean left atrial pressures were greater than 30 mm of Hg, had increases in heart rate, pulmonary arterial mean pressure, left atrial diameter, and left ventricular diastolic diameter. These changes were associated with decreased arterial O2 tension, decreased static and dynamic compliance, reduced lung volumes, and increased pulmonary resistance. Group-1 dogs, in which mean left atrial pressure was less than 30 mm of Hg, had moderate changes in hemodynamics, but no changes in pulmonary function, except during exercise when arterial O2 tension decreased.

Anthelmintic treatment of pastured dairy cattle in California

The relationship of anthelmintic treatment for subclinical gastrointestinal nematode parasitism with resultant milk production was studied on 3 California dairies where animals were maintained on a pasture-based nutritional program. All of the animals that started lactating (freshened) during a 12-month period participated in trials in which coumaphos was given as a feed top dressing to animals averaging 30 days into lactation. All of the animals that freshened during the subsequent 12-month period from 2 of the same 3 dairies participated in trials in which thiabendazole was administered at or within 2 weeks before freshening. Anthelmintic administration during 2 consecutive lactation cycles under the conditions of the present study resulted in no consistent reproducible significant changes in milk production.

Efficacy of repeated doses of levamisole, morantel, fenbendazole, and ivermectin against gastrointestinal nematodes in ewes

Levamisole, morantel, fenbendazole, or ivermectin was administered at 2-week intervals from May 1 through Sept 14, 1985, to breeding ewes (20 ewes/drug) infected with various gastrointestinal nematodes. All ewes had fewer gastrointestinal nematode eggs per gram of feces (epg) after 2 treatments, compared with pretreatment epg counts. Ewes administered ivermectin continued to have a low mean epg (0 to 3) throughout the study. The mean epg counts of ewes treated with levamisole increased from 3 to 483 during the study. This increase was similar to that of ewes treated with morantel (7 to 485 epg). The mean epg count of fenbendazole-treated ewes increased from 4 to 192 during the study. By the end of the study, the mean epg counts when expressed as a percentage of the pretreatment epg counts were 4% (ivermectin), 249% (fenbendazole), 627% (levamisole), and 630% (morantel). With the exception of the ivermectin-treated ewes, the epg count increased almost linearly in the ewes after the 2nd anthelmintic treatment. These data indicate that the gastrointestinal nematodes (including Haemonchus contortus) may have developed more resistance to levamisole and morantel than to fenbendazole. On the basis of the epg counts, resistance to ivermectin did not develop during the 4.5-month treatment period. The percentage of ewes shedding eggs after 2, 4, and 6 anthelmintic treatments was lowest for ewes treated with ivermectin (20%) and was similar (40%) for ewes treated with 1 of the other 3 anthelmintics. At the conclusion of the study, most of the ewes (90%) were shedding at least a small number of eggs, regardless of the anthelmintic treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma in situ of the glans penis and distal urethra

A case is presented of erythroplasia of Queyrat involving the distal glans penis surrounding the urethral meatus. Therapy with topical 5-fluorouracil was followed by recurrence within 14 months. Treatment by excision utilizing the Mohs technique demonstrated carcinoma in situ of over 5 cm of the distal urethra. Plastic surgical reconstruction produced a cosmetically and functionally normal penis.

A case of Dipylidium caninum in Baton Rouge, Louisiana

The relevant literature concerning human dipylidiasis has been reviewed with specific reference to the association of children and their pet dog and cats. A specific case is recounted which is considered to be typical of the condition as encountered by pediatricians and general practitioners.

Spontaneous osteogenic sarcoma in the rat

A spontaneous osteogenic sarcoma of the spinal column (tail, sacrum and lumbar regions) with metastases to the lungs, kidneys and right ovary were found in a 15-month-old BHE rat. The literature on spontaneous osteogenic sarcoma in rats indicates that this tumour is rare (0.22 per cent), occurs in several strains and has no sex, age or site predilections; non-metastatic cases are more common than metastatic ones.

Post-traumatic alterations in glutamine synthetase activity in peripheral and central nerves

Glutamine synthetase (GS) was assessed distal to the site of axonal injury in traumatized rat central (optic) or peripheral (tibial) nerve prior to and during periods of reactive PNS and CNS glial cell hypertrophy. GS activity in crushed optic nerve remained equivalent to that in unoperated control tissue at 2 days postoperatively, but rose by 30% at 7 and 12 days after surgery. In contrast, GS activity in traumatized peripheral nerve was significantly lower than in unoperated controls at 7 and 12 days postoperatively. Administration of mitotic inhibitor (AraC, cytosine arabinofuranoside) prevented significant trauma-induced alterations in GS activity in optic nerves at 7, and in peripheral nerves at 7 and 12 days postoperatively. Results suggest significant alterations in glial/Schwann GS activity after nerve fiber injury and that these alterations can be delayed/prevented by administration of mitotic inhibitors.

Impact of ozone on field-corn yield

Field corn (Zea mays L.) is the most important agricultural crop in the United States, and the major production areas are subjected to potentially damaging concentrations of ozone (O3). Since no information was available regarding the sensitivity of field-corn hybrids grown in the Midwest, plants of two hybrids ('Pioneer 3780' and 'PAG 397') were field grown in open-top chambers and exposed to O3 (7 h/day seasonal means of 0.015, 0.044, 0.073, 0.100, 0.129, and 0.156 ppm) for 83 days to determine the impact of O3 on grain yield. The air in the chambers was either charcoal filtered or nonfiltered with various constant amounts of O3 added to the ambient air (mean of 0.044 ppm) from 0900 to 1600 Central Standard Time. Also included was a nonchambered plot. A randomized complete block design incorporated three replicates of seven treatments. Foliar injury was noted on some plants at the elevated O3 concentrations but was never more than 5% on an individual leaf. Analysis of variance of the data indicated significant ozone effects on overall grain yield, 100-seed weight, seeds per cob, cob weight, and cob length, for both hybrids. Small reductions in overall yield were due to reduced individual seed weight. Larger overall yield reductions were due to reductions in seed weight and number. Three nonlinear models were tested to describe the responses of the hybrids to O3 and the models were not statistically different from each other. The Weibull survival function was used to test for heterogeneity of hybrid responses, and the responses were found homogeneous. The Weibull model predicted yield losses of 2.6% at 0.06 ppm and 16.3% at 0.10 ppm relative to 0.025 ppm O3. A comparison of the open plots with the nonfiltered air-chamber plots provided with the same O3 concentration revealed no significant chamber effects for any of the seed yield parameters.

The roles of reactive gliosis and mitosis on tropic factor production in traumatized nervous system tissue

Proximal stumps of rat sciatic nerves were attached to inlet ends of Y-shaped silastic implants and offered a 'choice' of growing toward an Elvax pellet containing homogenate from previously crushed optic nerve which had been exposed to saline or cytosine arabinofuranoside (AraC). Previous studies indicate that AraC administration inhibits reactive gliosis in crushed optic nerve. Preferential or exclusive growth of axons occurred in implant forks attached to pellets containing saline- (vs drug-) exposed optic nerve homogenates. In contrast, inhibition of Schwann cell mitosis had no discernible effect on tropic factor production in distal stumps of transected sciatic nerves. Tropic activity of homogenates from cultures containing reactive-like astrocytes was nearly 4 times higher than homogenates not containing these cells. Results suggest a possible link between formation of hypertrophic reactive astrocytes and production of neurotropic factor.

Efficacy of the tris-salt of 2 [(methoxycarbonylamino)-[2-nitro-5-(n-propylthio) phenylimimo] methylamino] ethane sulfonic acid against inhibited larvae of Ostertagia ostertagi

The tris-salt of 2-[(methoxy-carbonylamino) - [2-nitro-5-(n-propylthio) phenylimimo] methylamino] ethane sulfonic acid (MCA) was evaluated against naturally acquired gastrointestinal parasitism in cattle during spring in Louisiana to determine efficacy of the compound against inhibited early 4th-stage larvae (EL4) of Ostertagia ostertagi. Forty-three crossbred yearling beef heifers were grazed together on contaminated pastures between Mar 1 and Apr 18, 1984. On April 17, 3 of the 43 heifers were slaughtered. Analysis of worm population characteristics in the 3 cattle indicated sufficient numbers of O ostertagi EL4 and other worm genera and species in these cattle to pursue a valid evaluation of the anthelmintic efficacy of MCA. The remaining 40 heifers were removed from pasture on April 18. On April 24, they were allotted into 4 treatment groups (10/group) based on an equal distribution of body weights and on whether they were spring- or autumn-born cattle. On April 25, the cattle were treated as follows: group 1, nontreated controls; group 2, treated with MCA at 7.5 mg/kg of body weight by oral drench; group 3, treated with MCA at 15.0 mg/kg by oral drench; and group 4, treated with MCA at 20.0 mg/kg by oral drench. The cattle were then confined in drylot pens until May 7. Similar numbers of cattle from each group were killed over a 3-day period from May 8 to May 10 (13 to 15 days after treatment). Mean numbers of O ostertagi recovered from nontreated controls were: adults, 8,279; developing 4th-stage larvae, 2,806; and inhibited EL4, 12,070.(ABSTRACT TRUNCATED AT 250 WORDS)

Early diagnosis of experimental necrotizing enterocolitis using proton nuclear magnetic resonance

The purpose of this study was (1) to confirm an experimental model of aminophylline-induced necrotizing enterocolitis (NEC); and (2) to determine whether nuclear magnetic resonance (NMR) imaging, based upon proton relaxation values (T1, T2), could detect NEC during its early pathogenesis. Sixty male weanling Lewis rats (avg wt = 75 g) were randomly assigned to one of three experimental groups: (A) superior mesenteric artery (SMA) occlusion (1 min) + aminophylline treatment (40 mg/kg); (B) SMA occlusion; and (C) sham midline laparotomy (control). All surviving animals were sacrificed at 48 hr postoperation and a specimen of ileum was removed for light microscopy (LM), electron microscopy (EM), and NMR analysis. Percentage water content was determined for representative specimens. Mortality occurred only in experimental group A animals (18.2%; P less than 0.05), who had received aminophylline. Microscopy of ileum from sacrificed animals of this group showed changes ranging from mild cellular disruption to severe hemorrhagic necrosis. Early ultrastructural changes consistent with NEC were detectable with EM before LM. Proton relaxation results obtained with NMR showed significant prolongation of T1 (252.5 +/- 4.4 msecs; P less than 0.001) and T2 (69.3 +/- 1.4 msecs; P less than 0.025) during the first stages of NEC. NMR may indeed enable early, safe diagnostic imaging of NEC in infants receiving aminophylline, or those who are otherwise at increased risk for development of this disease.

Bronchial adenoma: a review of 51 patients

The cases of 51 patients with bronchial adenomas were reviewed. There were 43 bronchial carcinoids, 5 adenoid cystic carcinomas, 2 mixed tumors, and 1 mucoepidermoid carcinoma. The carcinoid group was divided into typical (31, 72%) and atypical (12, 28%) subgroups. Nine carcinoids (20%) were categorized as metastasizing adenomas; in this group, 7 lesions were atypical and 2 were typical. Thirty-two lobectomies, 7 bilobectomies, 8 pneumonectomies, 2 sleeve resections, and 2 tracheal resections were performed. Ten-year survival was 88% for patients with typical carcinoids and 59% for those with atypical carcinoids. In the group with adenoid cystic carcinoma, 1 patient died postoperatively, 1 had recurrence of the tumor, 2 were alive and free from disease 16 and 23 years later, and 1 died of heart disease at 11 years. The patient with mucoepidermoid carcinoma was alive without recurrence 15 years after operation. In conclusion, bronchial adenomas of the carcinoid type are potentially malignant. Their prognosis depends on the histology of the tumor, and on the presence of metastasis to the regional lymph nodes and distant organs.

3-Alkyl-3-hydroxyglutaric acids: a new class of hypocholesterolemic HMG CoA reductase inhibitors. 1

Derivatives of 3-hydroxy-3-methylglutaric acid (HMG), a portion of the substrate for HMG CoA reductase, were prepared and tested for their inhibitory action against rat liver HMG CoA reductase and for their hypocholesterolemic activity. Structure-dependent competitive inhibition was observed. Optimal structures had a free dicarboxylic acid with an alkyl group of 13-16 carbons at position 3. 3-n-Pentadecyl-3-hydroxyglutaric acid (3j) (IC50 = 50 microM) reduced serum cholesterol in the Triton-treated rat and HMG CoA reductase activity in the 20,25-diazacholesterol-treated rat.

Cut income taxes with reorganization planning

It is necessary to plan when reorganizing a corporate structure, to minimize taxes at the tax-exempt parent organization level and avoid unexpected tax consequences at year-end. With an awareness of the income tax rules, proper debt structuring during the reorganization phase is possible and should enable the financial manager to minimize total income tax.

Cellular origin of human lymphotoxin and its purification

The ability of various subsets of human mononuclear cells to produce human lymphotoxin (LT) was examined. Peripheral blood mononuclear cells were separated into OKT4+, OKT8+, and Leu-11a+ subpopulations by flow cytometry. Both OKT4+ and OKT8+ cells produced LT upon phytohemagglutinin (PHA) stimulation, but the OKT4+ T cells were the major source of LT. In contrast, Leu-11a+ cells failed to produce LT. The LT production and the proliferative response to PHA, of OKT4+ and OKT8+ cells, were inhibited by prostaglandin E2 and histamine. The LT, derived from PHA-stimulated peripheral blood lymphocytes, was purified by a procedure involving Blue-agarose, Con A-Sepharose chromatography, preparative gradient polyacrylamide gel electrophoresis and preparative sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The LT activity was recovered from SDS gel with major activity peak in the Mr 76,000 region and the minor activity peak in the Mr 24,000 region. The LT derived from 1788 lymphoblastoid cell line also showed heterogeneity on SDS gel. The activity was recovered from two peaks in the region of Mr 70,000 and 20,000.

22-Hydroxycholesterol derivatives as HMG CoA reductase suppressors and serum cholesterol lowering agents

A series of 22-hydroxycholesterol derivatives with a modified side chain terminus was prepared. These agents were evaluated in vitro and in vivo for their ability to suppress HMG CoA reductase, the rate-limiting enzyme of cholesterol biosynthesis. In tissue culture assays, 22-hydroxycholesterol as well as the side chain modified analogues were potent inhibitors of HMG CoA reductase. However, only those sterols with a modified side chain terminus were effective suppressors of liver reductase when administered ig to rats. 22-Hydroxy-25-methylcholesterol (4a) and 25-fluoro-22-hydroxycholesterol (15a) significantly lowered serum cholesterol levels when administered ig to primates; 25-chloro-22-hydroxycholesterol (15b) and the analogue with a cyclopropyl terminus, 20b, were ineffective. The cholesterol-lowering sterols did not significantly alter lipoprotein levels; however, the two compounds have been shown to inhibit acyl-coenzyme A:cholesterol acyl-transferase (ACAT) in tissue culture studies.

Enhanced proliferation of WI38 cells in the presence of glucocorticoid-conditioned medium

The addition of hydrocortisone (HC) or dexamethasone (DEX) to WI38 cells at subcultivation is known to result in increased saturation densities (20-40%). We report that maximal increases in saturation density are, however, only observed if HC is added to the culture shortly after subcultivation. We have found that the proliferative response of WI38 cells to glucocorticoids is mediated by a secondary stimulatory factor(s) present in medium-conditioned by cells in the presence of the hormone. Control cultures refed with medium conditioned in the presence of HC for the first 24 h after seeding (24 h HC-CM) achieve saturation densities 20-40% higher than cultures refed with either medium conditioned in the absence of the hormone (24 h CM) or 24 h CM supplemented with fresh HC. Furthermore, WI38 cultures remain responsive to the stimulatory activity present in 24 h HC-CM throughout the growth cycle. The stimulatory effects of 24 h HC-CM are enhanced by repeatedly refeeding cultures; WI38 cells refed every 2 days with 24 h HC-CM demonstrate an extended period of logarithmic growth and achieve densities 2-3 times higher than controls. A preliminary characterization of this activity shows it to be of low molecular weight (MW) (dialyzable using 12 000 MW cut-off tubing) and heat-stable (75 degrees C).

Holoprosencephaly in a bovine calf

Holoprosencephaly, a rare brain malformation previously unreported in the bovine species, was observed in a female Hereford calf. The malformation was characterized by lack of the longitudinal cerebral fissure and the falx cerebri with fusion of the cerebral hemispheres and a single hydrocephalically dilated lateral ventricle, absence of olfactory bulbs and nerves, corpus callosum and septum pellucidum, and heterotopia. The face was flat. There were mild ocular hypotelorism and severe microphthalmia. The morphological features of this bovine case were compared to those of human infants, and various possible etiologic factors and pathogenesis were discussed.

Metal/cement interface strength in cemented stem fixation

To characterize the strength of the interface between stem-type metal implants and bone cements, a fracture mechanics parameter was used. This parameter, the critical strain energy release rate (Gc), was determined from "push-out" tests of cylindrical specimens. The specimens, formed using molds of bone, were maintained and tested at body temperature. The strength of interfaces formed with cancellous bone surrounding the cement mantle was significantly less than the strength of those formed in apposition to cortical bone. A marked degradation of strength was found with saline immersion for SS316LVM/cement interfaces formed with Zimmer regular, Simplex-P, and Zimmer LVC cements. After 60 days of immersion the interface Gc was only 10-20% of the value for bulk cement. Interfaces formed with thin-film polymethylmethacrylate-precoated metals (SS316LVM, Co-Cr-Mo, and Ti-6A1-4V) yielded "dry" Gc values one order of magnitude greater than those measured with interfaces formed with uncoated metals. Moreover, the strength of precoated SS316LVM/cement interfaces formed with all three brands of cement did not change after saline immersion for 60 days.

Prevention of the hyperlipidemic serum or LDL-induced cellular cholesterol ester accumulation by 22-hydroxycholesterol and its analogue

Incubation of monkey arterial smooth muscle cells with hyperlipidemic serum or low-density lipoproteins (LDL) produces intracellular cholesterol ester accumulation. Increased esterification of free cholesterol within the cell may account for this effect. To examine such a possibility, oxygenated sterols were used to block cholesterol esterification. The increased esterification of free cholesterol by smooth muscle cells and human skin fibroblasts, through their exposure to hyperlipidemic lipoproteins, was inhibited by 22-hydroxycholesterol and its analogue, SC-32561 (22-hydroxy-25-fluorocholesterol). The hyperlipidemic LDL-stimulated elevation in the cholesterol ester content of the smooth muscle cells was also prevented by these sterols. This reduction in cellular cholesterol ester did not coincide with an increase in free cholesterol. 22-Hydroxycholesterol also blocked the stimulation of the esterification of cholesterol due to 25-hydroxycholesterol. In the absence of lipoproteins, 22-hydroxycholesterol and SC-32561 had a minor effect on the incorporation of [14C]oleate into cholesterol esters, and efficiently reduced sterol synthesis in fibroblasts and smooth muscle cells. 22-Hydroxycholesterol and SC-32561 had the additional effect of lowering the number of cell-surface LDL receptors to a greater extent than did hyperlipidemic LDL. The presence of 22-hydroxycholesterol did not alter the interaction of normal LDL with the receptor. Oxygenated sterols recovered in the cell represented 4-21% of the total sterol content. The level of intracellular oxygenated sterols was significantly reduced by the presence of lipoproteins in the culture media. Due to the multiple effects of the oxysterols, they were not effective as tools in determining the contribution of acyl-coenzyme A:cholesterol acyltransferase enzyme activity to the intracellular pool of cholesterol esters. These results indicated that 22-hydroxycholesterol and SC-32561 effectively blocked the hyperlipidemic LDL-stimulated increase in smooth muscle cell cholesterol ester content by lowering cholesterol esterification, reducing cholesterol synthesis and down-regulating LDL cell-surface receptors.

Esophageal impaction in BHE rats

Spontaneous esophageal impaction was observed in 33 BHE rats, aged 6 to 26 months, from 157 rats which died or were killed when moribund due to spontaneous conditions. The clinical course lasted less than 48 hours and included weakness, excessive salivation, forward head motions, matting of chin and perioral hair with bedding material, followed by recovery or death. In some animals, the clinical episodes reoccurred. The esophagus was dilated (up to 7.0 mm) and impacted with bedding or food. The caudal half of the esophagus was affected more than the cranial half. The esophageal muscle was thin and pale at the site of impaction. Histologically, there was esophageal myodegeneration.