Ethylene oxide sensitivity in hemodialysis patients

Sera from 138 patients who had experienced hypersensitivity-type reactions while on hemodialysis (reactors) were examined retrospectively by the radioallergosorbent test (RAST) for specific IgE antibody to ethylene oxide (ETO). Seventy-eight hemodialysis patients without a history of reaction were also evaluated as controls. Elevated serum RAST values (greater than 2.0) were more common in reactors (63%) than in controls (11%, p less than 0.001). In a second study, RAST assays were performed using human serum albumin conjugated to ETO (HSA-ETO) as antigen and also using a concentrate of fluid used to rinse ETO-sterilized dialyzers ("dialyzer extract") as antigen. The RAST ratios obtained with HSA-ETO were similar to those obtained using the dialyzer extract (rank order correlation coefficient = 0.829, p less than 0.001). In a third study, RAST inhibition was demonstrated both by HSA-ETO and dialyzer extract. Our results, extending previously published reports, suggest that hypersensitivity to ETO might play an important role in hemodialysis-associated hypersensitivity-type reactions.

Activation of transcription by two factors that bind promoter and enhancer sequences of the human metallothionein gene and SV40

Genetic analysis of eukaryotic transcriptional promoters has revealed that protein-coding genes often contain a complex array of cis-control elements consisting of upstream activator sequences and enhancer elements. The metallothionein genes provide a useful example for dissecting the action of multiple interspersed control elements that govern both basal level and regulated expression in animal cells. The human metallothionein (hMTIIA) promoter has been analysed in detail and found to contain no less than five distinct control elements in the 5' flanking regions of the gene that mediate specificity and regulation of transcription. These different control elements can be functionally subdivided into two categories: basal and induced elements. There are several distinct basal recognition sequences, which include a TATA-box, a GC-box, and at least two basal level enhancer (BLE) sequences, that function like classical enhancer elements. The hMTIIA gene also responds to induction by heavy metals and by steroid hormones through the action of metal regulatory elements (MRE) and glucocorticoid responsive elements (GRE). Here we report the identification of two cellular DNA-binding proteins that interact selectively with sequences governing the basal level expression of hMTIIA. One of these factors is a novel activator protein (AP1) that interacts with sequences in the BLE of hMTIIA and also binds to a site within the 72-base pair (bp) repeats of the simian virus 40 (SV40) enhancer region. The second protein has been purified to homogeneity and shown to be transcription factor Sp1 which recognizes and binds to a single GC-box element within the hMTIIA promoter.

Urinary diagnostic indices in preeclampsia-associated oliguria: correlation with invasive hemodynamic monitoring

Seven oliguric women with preeclampsia were identified among patients admitted for obstetric care at Jefferson Davis or Hermann Hospitals in Houston, Texas. Urinary diagnostic indices (including urine-to-plasma ratios of creatinine, urea nitrogen, and osmolality) were generally consistent with a prerenal etiology for the observed oliguria. Conversely, invasive hemodynamic monitoring revealed a volume replete state in five of seven preeclamptic women studied. All patients were observed to have markedly elevated urinary sodium concentrations. The transient oliguria observed in these patients spontaneously resolved without diuretic or hyperosmolar agents. We conclude that oliguria is a poor index of volume status in preeclamptic women. Urinary diagnostic indices may also be misleading if used to guide fluid management in these patients. Finally, the clinical significance and therapeutic alternatives relating to preeclampsia-associated oliguria are discussed.

Quantitative analysis of cellular glutathione by flow cytometry utilizing monochlorobimane: some applications to radiation and drug resistance in vitro and in vivo

An assay using a bimane derivative has been developed to detect free glutathione (GSH) in individual viable cells by flow cytometry. Monochlorobimane [syn-(ClCH2CH3)-1,5-diazabicycla[3.30]acta-3,6-diene-2,8-dio ne], itself nonfluorescent, reacts with GSH to form a highly fluorescent derivative. High pressure liquid chromatography analysis showed that, using specific staining conditions, the only low molecular weight fluorescent derivative formed in Chinese hamster ovary cells was that formed with GSH. Very little reaction with protein sulfhydryls was observed. Rates of GSH depletion in Chinese hamster ovary cells exposed to diethylmaleate were essentially the same, whether measured by relative fluorescence intensity, by flow cytometry or by enzymatic assay on cellular extracts. This method was shown to be useful for measurement of GSH resynthesis, uptake, and depletion by prolonged hypoxia and misonidazole treatment. Since measurements are made on individual cells, cell-to-cell variation and populational heterogeneity in GSH content are revealed by flow cytometry. Although under most conditions in vitro GSH content is relatively homogeneous, under certain circumstances, such as release from hypoxia, heterogeneity in populational GSH levels was observed. The significance of this heterogeneity is discussed in regard to the induction of gene amplification and drug resistance by transient hypoxia. Numerous subclones of Chinese hamster ovary cells selected by growth in Adriamycin or methotrexate-containing medium express elevated levels of GSH per cell. The method was extended to quantitate the GSH content of cells excised from EMT-6/SF mouse tumors that had been treated in vivo with L-buthionine-S-R-sulfoximine, an inhibitor of GSH synthesis. The bivariate analysis (forward angle light scatter versus monochlorobimane fluorescence) of cells derived from these tumors gave excellent resolution of normal and tumor cells and demonstrated extensive heterogeneity in the tumor cell population with respect to GSH content per cell.

Fingerprinting Candida albicans

A new method of typing Candida albicans based on immunoblotting is described. Isolates were disrupted by a mixture of enzymic pretreatment with alpha-mannosidase followed by sonication. They were then stained using a modified ELISA system by a rabbit hyperimmune serum raised against a single isolate, C. albicans NCTC 3153. The 190 isolates examined from the London Hospital produced 16 different types. Type 1 accounted for 43% of the isolates and was the commonest type outside the intensive care unit. Type 2 caused an outbreak of systemic candidosis on the intensive care unit. The technique was much more sensitive than the serotyping and morphotyping methods and lacked the phenotypic variability of the biotyping procedure previously used to define the outbreak. The gel-to-gel variation precludes its use in large scale epidemiological work. Its value lies in identification of outbreaks so that they can be controlled by the introduction of measures to prevent cross-infection.

Squamous and trophoblastic cells in the maternal pulmonary circulation identified by invasive hemodynamic monitoring during the peripartum period

The antemortem diagnosis of amniotic fluid embolism has traditionally relied on the identification of amniotic fluid debris in the maternal circulation by central venous or pulmonary arterial catheterization. Pulmonary artery blood specimens from 14 term pregnant women with severe pregnancy-induced hypertension suggest that squamous or trophoblastic cells may be normally present in the maternal pulmonary circulation during the peripartum period and that their presence is not pathognomonic of clinically significant amniotic fluid embolism.

Evaluation by computerized axial tomography of eclamptic women with seizures refractory to magnesium sulfate therapy

Over a 1-year period, seven eclamptic patients with repetitive seizures while receiving therapeutic levels of intravenous magnesium sulfate were evaluated by computerized axial tomography. In five patients brain abnormalities were identified, which included diffuse cerebral edema (one), cerebral venous thrombosis (two), and low density white matter (two). Clinical management of eclamptic women on the basis of structural central nervous system abnormalities documented by computerized tomography appears to warrant further investigation.

Comparison of low- and high-volume irrigation-aspiration systems for extracapsular cataract extraction

A low-volume irrigation-aspiration system with a 1-mm tip (0.3-mm aspiration port) has been developed for extracapsular cataract extraction. This autoclavable system uses approximately 36% less irrigating fluid during the irrigation and aspiration of cortical material when compared to currently available models. The time required for cortical aspiration is also shortened by 33%. After three years of clinical experience with the low-volume system at the Miami Veterans Administration Medical Center, where almost all extracapsular cataract surgery is now performed with the new system, there have been no adverse effects and subsequent capsulotomy has rarely been necessary.

The role of nasointestinal intubation in elective colonic surgery

One hundred thirty-eight consecutive patients undergoing elective colonic resections were treated prospectively and randomly with either a long intestinal (Cantor) tube preoperatively, a nasogastric tube placed intraoperatively, or no gastrointestinal tube at all. Patients were evaluated for length of hospital stay, duration of postoperative ileus, adequacy of intraoperative intestinal decompression, gastric dilatation, and operative complications. No significant difference could be seen in the tubed or no-tube group.

Effect of diclofenac sodium on the arachidonic acid cascade

The anti-inflammatory activity of nonsteroidal anti-inflammatory drugs is primarily attributed to inhibition of distinct steps in the arachidonic acid cascade, particularly, the cyclo-oxygenase pathway. Diclofenac sodium, a compound of this class of drugs, appears to have a dual effect since it also regulates the lipoxygenase pathway. Study of appropriate cell systems (leukocytes and whole blood in rats) demonstrates that diclofenac's potent inhibition of cyclo-oxygenase activity causes a sharp reduction in the formation of prostaglandin, prostacyclin, and thromboxane products, all key mediators of inflammation. Recent work discloses that at higher concentrations, diclofenac sodium also reduces the formation of products of the lipoxygenase pathway (5-hydroxyeicosatetraenoic acid, leukotrienes). The mechanism by which this evolves, however, appears to be unrelated to direct inhibition of lipoxygenase. Instead, by enhancing its reincorporation into triglycerides, diclofenac sodium reduces the intracellular level of free arachidonic acid.

Arrhythmia susceptibility and myocardial composition in diabetes. Influence of physical conditioning

Abnormal myocardial composition in diabetes mellitus has been described, but the effects on ventricular vulnerability have not been defined. We have assessed the susceptibility to arrhythmias in a canine model after 1 yr of mild diabetes induced by alloxan. Since physical conditioning can affect metabolic abnormalities in diabetes, this intervention has also been evaluated. Group 1 served as controls and groups 3 and 4 were diabetic. Animals in the latter group as well as nondiabetic controls of group 2 were exercised on a treadmill for the last 8 mo of the experiment. After 1 yr, anesthesia was induced with chloralose for vulnerability studies. The ventricular fibrillation threshold of 24.4 +/- 1.9 mA in group 3 was significantly less than in normals (45.1 +/- 2.2). Spontaneous arrhythmias were also more prevalent in diabetics during acute ischemia (group 3-A). Increased ventricular vulnerability after epinephrine infusion was present in the sedentary diabetes despite normal ventricular function responsiveness. In a superfused preparation of myocardium, resting membrane potential and action potential amplitude were normal in diabetics, and beta-adrenergic stimulation shortened repolarization more than in controls. Myocardial collagen concentrations, which included an interfibrillar distribution on morphologic examination, were increased in group 3. In the trained diabetics of group 4 the basal vulnerability thresholds and responses to epinephrine were normal. While myocardial collagen levels were normal, cholesterol and triglyceride increments persisted. Thus, in mild experimental diabetes, enhanced susceptibility to arrhythmias exists; this susceptibility may be based on a combination of nonhomogenous collagen accumulation affecting local conduction and increased electrophysiologic sensitivity to catecholamines.

Arterial intimal embrittlement. A possible factor in atherogenesis

Sections of aorta, coronary artery, basilar artery and vena cava were collected at autopsy. Macroscopically normal intimal specimens were removed by stripping. Intimal collagen was measured as hydroxyproline. Intimal film embrittlement was measured in vitro by a bursting volume distensibility test developed in our laboratory. There was an average increase of over 100% in the collagen content of apparently lesion-free human arterial intima on aging over a fifty-year period. This includes an increase of 113% for aortic intima, 49% increase for coronary artery intima, and an increase of 158% in collagen in basilar artery intima. In contrast the collagen level in the vena caval intima decreases on aging, by 42% in fifty years. The large increase in collagen in arterial intima is accompanied by a large increase in intimal embrittlement. The decreasing collagen content of the venous intima on aging results in increased distensibility. Increased aortic intimal film embrittlement (lower distensibility) correlates with age (R = 0.699), but even better with intimal collagen (R = 0.911), suggesting that aortic intimal collagen level is a more important determinant of intimal embrittlement than age. Men, older than 55, have significantly higher aortic intimal collagen levels than women. Embrittlement of arterial intima should make it more susceptible to injury under the pulsatile pressure of the blood. Decreased venous intimal collagen and greater distensibility on aging could be factors in the development of venous valvular insufficiency and varicose veins. However, our study of veins was performed primarily as a control in this instance. Fundamental elements in the atherogenic process are increased intimal collagen, increased intimal brittleness, endothelial injury, followed by intimal cell proliferation. In the vena caval intima on aging there is decreased collagen, increased intimal distensibility, no injury due to increased pulse or blood pressure, and, therefore, no cell proliferation and no intimal lesion.

A scanning electron-microscopic study of the muscle layer of the canine gallbladder

A connective tissue digestion and removal technique utilizing collagenase and hyaluronidase incubation followed by treatment with 8 N hydrochloric acid successfully revealed the muscular components within the gallbladder wall of the dog, allowing three-dimensional visualization with the scanning electron microscope. The muscle adjacent to the serosa appeared as a homogeneous layer with few discontinuities. In contrast to this were the more superficial muscle layers which were arranged as a meshwork of interlacing smooth muscle bundles of various size, the interstices of which were filled with cellular connective tissue. These gaps in the muscle layer varied in size, becoming larger as the muscle bundles tapered out just below the mucosal aspect of the gallbladder wall.

The effects of diclofenac sodium on arachidonic acid metabolism

Evidence has been presented that inhibition by diclofenac sodium of the production of leukotrienes by cells participating in the inflammatory process is due to a decreased availability of intracellular arachidonic acid which results from enhanced uptake of the substrate into triglyceride pools. The diminished leukotriene production does not result from direct inhibition of 5-lipoxygenase or phospholipase A2. Reduced availability of arachidonic acid would also limit production of prostaglandins, although in this case manifestation is obscured by the potent inhibitory effect of diclofenac sodium on cyclooxygenase. This recently discovered action of diclofenac sodium, which has been characterized by studies on isolated leukocytes, appears to be operative in vivo. Consistent with this mechanism, and not explainable by classical cyclooxygenase inhibition, diclofenac sodium inhibited leukotriene production in whole blood from drug-treated animals and also suppressed leukocyte infiltration of subcutaneously implanted sponges. The latter effect contrasts with increased infiltration frequently obtained with other NSAIDs and thought to reflect enhanced production of leukotrienes. In conclusion, the findings suggest that patient acceptance or preference for diclofenac sodium is not merely subjective but has a logical scientific basis.

Combined intrauterine and ovarian pregnancy. A case report

A case of combined ovarian and intrauterine pregnancy occurred. The ovarian pregnancy was an incidental finding during cesarean section. A literature survey revealed only 17 cases of combined ovarian and intrauterine gestation.

Reactions during hemodialysis caused by allergy to ethylene oxide gas sterilization

In patients receiving long-term hemodialysis (HD), we have examined the presence of IgE-dependent sensitization to ethylene oxide (EO) gas, which is used for sterilization of disposable medical products including dialyzers. Serum was obtained from 25 patients who experienced acute allergic reactions during HD, five patients receiving HD with isolated eosinophilia, and 37 unselected patients receiving HD. Sera from 22 of 25 of the allergic reaction group and from five of 35 of the unselected group were demonstrated to contain IgE antibodies with specificity for EO. Corresponding IgG antibodies were also present. No such antibodies were detected in serum from normal controls or ragweed-allergic patients. The serum from one patient with isolated eosinophilia had a borderline elevated IgE antibody level. These results demonstrate a close relationship between the presence of IgE antibodies to EO and HD-related allergic reactions in this patient population.

Outbreak of systemic Candida albicans in intensive care unit caused by cross infection

The first documented outbreak of systemic candidosis shown to be due to cross infection with a particular strain of Candida albicans is reported. Over nine months in an intensive care unit 13 patients developed definite and one probable systemic candidosis. Twenty five further patients had superficial candidal infections. The strain that caused the outbreak (serotype A, morphotype A1, biotype 0/(1)5 5/7) was responsible for all the cases of systemic candidosis acquired in the intensive care unit, 11 (44%) of the superficial candidal infections in the unit, and 17% of candidal infections outside the unit but in the same hospital. The strain was also isolated from oral swabs taken from four nurses working in the unit and the hands of one of these nurses. Two out of 17 nurses were shown to have acquired the strain on their hands when examined immediately after nursing systemically infected patients. No environmental source could be identified. The strain also showed enhanced survival in handwashing experiments and was relatively resistant to Hibiscrub. Management of patients with systemic candidosis might include measures to prevent cross infection and handwashing with disinfectants that are active against candida.

Characterization of Limulus amoebocyte lysate-reactive material from hollow-fiber dialyzers

Hollow-fiber hemodialyzers containing cellulose-based membranes have been shown to produce positive results with the Limulus amoebocyte lysate test. This study was undertaken to determine whether endotoxin was causing the reaction. Rinses from 45 parallel-plate and hollow-fiber dialyzers from eight different manufacturers were tested before and after treatment with cellulase, using three lysates and four Limulus amoebocyte lysate methods. In addition, four in vitro cellular methods--human leukocytic pyrogen, lymphocytic activating factor, peritoneal macrophage, and arginase release--were used to evaluate endotoxin activity. The substance causing the reaction was identified by chromatographic methods. Results indicate that the Limulus amoebocyte lysate reactive material is cellulose derived and not pyrogenic.

Comparison of chemical analyses of hollow-fiber dialyzer extracts

Hollow-fiber hemodialyzers containing cellulose-based membranes have been shown to produce positive results with the Limulus amebocyte lysate (LAL) test. This study was undertaken to determine whether endotoxin was causing the reaction. Rinses from 45 parallel-plate and hollow-fiber dialyzers from eight different manufacturers were tested using three lysates and four LAL methods. In addition, four in vitro cellular methods--human leukocytic pyrogen, lymphocytic activating factor, peritoneal macrophage, and arginase release--were used to evaluate endotoxin activity. The substance causing the reaction was identified using chromatographic methods. Results indicate that the LAL-reactive material is cellulose derived and is not pyrogenic.

Allergy to ethylene oxide in chronic hemodialysis patients

Almost a decade ago, a single chronic hemodialysis patient in Hamilton, Ontario, Canada, who was experiencing recurrent acute reactions during hemodialysis was found to have become allergic to ethylene oxide gas (EO). This observation recently provided a stimulus to examine the possibility that others exhibiting acute allergic-type reactions during hemodialysis might be similarly sensitized. Serum was obtained from 27 reacting patients and tested in a radioallergosorbent test (RAST) for antibodies to EO. The test was positive for 22 of these sera. EO-related specificity of the antibodies was confirmed. However, EO sensitization was not found in other hemodialysis patients with isolated eosinophilia. In a survey of the current Hamilton chronic hemodialysis population for EO-related antibodies, 9% had a positive allergy skin test and 12% had a positive RAST. The sensitized individuals had no distinctive symptoms. The lesser sensitivity of the skin test contrasts with usual findings in allergic individuals; however, the use of histamine and codeine in chronic hemodialysis and peritoneal dialysis patients might well explain a reduced sensitivity of the EO-related allergy skin test. Chronic peritoneal dialysis could not be invoked as a source of sensitization. None of these patients had a positive skin test or RAST for EO-related antibodies that could be attributed to peritoneal dialysis.

Electric infusion pole adjuster

A newly developed electric motorized infusion pole stand permits the surgeon to rapidly and accurately alter the rate and pressure of infusion during intraocular surgery.

Comparison of somatostatin distribution in pancreatic duct ligated rats and streptozotocin diabetic rats

The somatostatin content in the pancreas and gastrointestinal tract was examined in normal, streptozotocin (STZ)-diabetic and pancreatic duct ligation (PDL) rats. The somatostatin content in the pancreas and gastric antrum in the STZ-diabetic group showed a higher concentration compared with those in the normal control group (p less than 0.001). The somatostatin content in the duodenum in the PDL group showed a higher concentration compared with those in the sham-operated group (p less than 0.02). There was no significant increase in the lower gastrointestinal tract in the normal, STZ and PDL groups. These facts suggest that the concentration of somatostatin varies according to tissues and organs and that the distribution of somatostatin in chronic pancreatic injury caused by PDL is different from that in diabetes mellitus cases or controls.

Ascorbic acid in lymphocytes: cell preparation and liquid-chromatographic assay

Measurements of ascorbic acid concentration in leukocytes by "high-performance" liquid chromatography (HPLC) provides better nutritional assessment, leading to better management, particularly of presymptomatic and critically ill patients. This procedure includes a simple, reproducible cell-separation technique that requires no more than 2 mL of whole blood. Cell populations are separable with greater than 95% purity and greater than 99% viability. Ascorbic acid is assayed by HPLC. The vitamin can be reproducibly quantified in concentrations as low as 0.1 microgram/mL of cell extract. The chromatographic procedure is very rapid, analysis being completed within 15 min after specimen preparation. The assay is suitable also for urine and protein-free filtrates of plasma and of other biological materials. Reference intervals for plasma, mononuclear leukocytes, and polymorphonuclear leukocytes were established. A preliminary clinical evaluation revealed that hospital patients were at a greater risk of ascorbic acid deficiency than expected.

Ascorbic acid in lymphocytes: cell preparation and liquid-chromatographic assay

Measurements of ascorbic acid concentration in leukocytes by "high-performance" liquid chromatography (HPLC) provides better nutritional assessment, leading to better management, particularly of presymptomatic and critically ill patients. This procedure includes a simple, reproducible cell-separation technique that requires no more than 2 mL of whole blood. Cell populations are separable with greater than 95% purity and greater than 99% viability. Ascorbic acid is assayed by HPLC. The vitamin can be reproducibly quantified in concentrations as low as 0.1 microgram/mL of cell extract. The chromatographic procedure is very rapid, analysis being completed within 15 min after specimen preparation. The assay is suitable also for urine and protein-free filtrates of plasma and of other biological materials. Reference intervals for plasma, mononuclear leukocytes, and polymorphonuclear leukocytes were established. A preliminary clinical evaluation revealed that hospital patients were at a greater risk of ascorbic acid deficiency than expected.

Caring for Indochinese refugees

A refugee camp in Hong Kong and a health center in Los Angeles provide data on patterns of health care among Indochinese refugees. American physicians need to be aware that incoming refugees use both Western and traditional Chinese models of medical care. In addition, they are subject to special psychologic problems resulting from their past ordeals and their resettlement in a different country. Increased emergency aid should be provided to geographic areas with large concentrations of refugees.

Ankle-knee synchronous knee lock mechanism: a revision

An ankle-knee synchronous mechanism in a new endoskeletal above-knee (A-K) prosthesis has been designed and a preliminary clinical study has been conducted. A revision of the knee mechanism which is mainly focused on the basis of reducing the energy cost of the prosthetic wearer has been developed. It provides multiple position of the knee lock. It also provides anterior placement of the knee joint and a synchronous motion with the ankle joint. It enables the prosthetic wearer to minimize the effect of hip extensor contraction, to stabilize the knee, and maximize the sense of security and to balance the body over the artificial limb through the stance phase of gait. It permits the amputees to assume various body postures which enable them to perform daily activities. A new concept for alignment of A-K prosthesis is accomplished by using a weight bearing line instead of a trochanter and ankle (TKA) line, especially for the short A-K amputees. Deletion of the inertia control mechanism becomes possible by simply inserting a bumper in the knee to prevent terminal impact at swing phase and a built in coil spring acts as a knee extension aid.

Surgical and medical experience with 734 premature infants with patient ductus arteriosus

During the past 5 years, patent ductus arteriosus (PDA) presented in 734 preterm infants (less than 2.5 kg and 37 weeks gestation) of 2,532 admissions (29%). The ductus presented with murmur, bounding pulses, and often congestive heart failure. Medical treatment consisted of the following: fluid restriction, furosemide, respiratory support, and rarely digoxin. The patients who were unresponsive to medical treatment had surgical ligation (306 of 734 or 42%). The patients who had ductal ligation were smaller, i .e., 82% of the surgical patients weighed less than 1.5 kg as compared to 38% of the medical patients. Of those patients weighing less than 1.5 kg, the surgical and medical groups were compared and the following observations made: The incidence of respiratory distress syndrome was greater in the surgical group (86% or 216 of 252 patients versus 69% or 111 of 161 medical patients, p less than 0.001) and the long-term survival was better (89% or 224 of 252 surgical patients versus 77% or 124 of 161 medical patients, p less than 0.005). In addition, the average duration of intubation was shorter in this surgical subgroup (8.9 versus 13.6 days). Significant left atrial enlargement and echocardiographic left atrial/aortic (LA/Ao) ratios of greater than 1.5:1 occurred in 58% or 171 of 290 surgical patients versus 32% or 59 of 190 medical patients (p less than 0.001). During the first 3 years of this study (medical treatment averaged 5 days), the duration of intubation in the surgical patients averaged 15.2 days; by comparison, in the last 2 years of this study (medical treatment averaged 1 to 2 days), the duration of intubation was 6.5 days (p less than 0.001). Necrotizing enterocolitis (NEC) occurred in 11% or 46 of 428 medical patients versus 0.3% (one of 305 patients) in the ligated group postoperatively (p less than 0.001). Late deaths were related to lung disease, central nervous system problems, NEC, and so on. From this study, it was determined that ligation of a significant PDA is associated with (1) zero surgical risk, (2) a reduced incidence of NEC, (3) reduced duration of intubation, especially with early ligation, and (4) improvement in late survival. Thus the surgical approach is our treatment of choice for a refractory PDA.

Specificity of power improvements through slow and fast isokinetic training

College age males performed maximal two-legged isokinetic knee extensions three times per week for 6 wk at either 60 degrees/s (slow) or 300 degrees/s (fast) or both 60 and 300 degrees/s (mixed). The velocity specific and action specific (two-leg vs. one leg) improvements in peak torque (PT) were compared to a placebo group receiving low-level muscle stimulation. The slow group improved PT significantly (P less than 0.05) more than the placebo group only at its training velocity (60 degrees/s) and more so when the specific two-legged training action was mimicked (+32% with two legs vs. +19% with one leg). The mixed group enhanced PT by 24 and 16% at their respective training velocities of 60 and 300 degrees/s. These improvements were significantly larger than placebo and also significantly larger than the 9% improvement observed at the midvelocity of 180 degrees/s. The training specificity demonstrated by the slow and mixed groups suggest that neural mechanisms contributed to their improvements in power. This is supported by their unchanging muscle morphology. Training solely at 300 degrees/s (fast) however improved PT significantly more than placebo not only at the training velocity (+18%), but also at a slower velocity of 180 degrees/s (+17%). The fast group demonstrated a significant enlargement (+11%) of type II muscle fibers. These data suggest type II fiber hypertrophy to be a plausible mechanism for the nonspecific improvement of the fast group; however, a neurological adaptation that enhances power at and below the training velocity cannot be excluded.

Central serous choroidopathy in the Hallermann-Streiff Syndrome

Central serous choroidopathy was observed in a young patient with the Hallermann-Streiff syndrome. Typical features of this syndrome include microphthalmos, proportionate dwarfism, dyscephaly with birdlike facies, dental abnormalities, and hypotrichosis. Exceptional aspects of this case include age of onset (11 years), high hyperopic refractive error (+ 13.00 sphere), and multiple recurrences caused by six separate documented leaks from the choroid. Fundus changes previously reported in the Hallermann-Streiff syndrome, interpreted as chorioretinal pigmentary changes, may have been secondary to previous undiagnosed central serous choroidopathy. Periodic ophthalmoscopy should be performed and may detect unrecognized episodes of central serous choroidopathy for which photocoagulation would be beneficial.

The effect of diabetes on leucine and fucose incorporation into PNS myelin proteins

Peripheral neuropathy is a common complication associated with diabetes mellitus. Segmental demyelination and other pathological changes frequently accompany loss of sensory amd motor nerve function. Morphological changes seen in diabetic nerve myelin may be a result of altered Schwann cell metabolism under hyperglycemic conditions. Using both alloxan and streptozotocin - induced diabetic rats of 2, 4 and 8 months duration of diabetes, metabolic changes in isolated sciatic nerve myelin were assessed using a double-label in vitro incubation system. Incorporation of 3H-fucose and 1-14C-leucine into myelin was determined per microgram protein. Specific activities of incorporated protein precursors were compared as a ratio of fucose to leucine. Using the Newman-Kuels test for multiple comparisons, statistically significant increases were found in the incorporation ratios of diabetic rats at 2 and 4 months of diabetes when tested against age-matched controls.

Angiosarcoma of the heart: ultrastructural study

Two angiosarcomas of the heart, both arising from the right atrium, were studied with the electron microscope. Ultrastructural characteristics of angiomatous development were demonstrated both at the better differentiated vascular areas and at the less differentiated, spindle-cell foci. Both tumors were dominated by immature endothelial cells. These cells were associated with primitive mesenchymal cells and transitional forms of pericytes. Intracytoplasmic lumen formation and junctional specialization with neovascular development are unique features of angiogenesis in these tumors. Ultrastructural studies may provide useful diagnostic features separating a true malignant vascular neoplasm of endothelial cell origin from other forms of mesenchymal neoplasia that may have a prominent stromal vascular component.