Scanning electron micrographs of sheep erythrocytes showed that attachment of the alpha hemolysin produced by Escherichia coli resulted in the formation of spherocytes, with 10 to 20 small projections spaced relatively evenly over the surface of the erythrocyte membrane. This shape change was induced within 5 min after treatment. If the hemolysin concentration was reduced to a level which would lyse only a fraction of the total erythrocytes, the affected cells were easily identified against a background of normal, unaffected cells. Unlike sodium lauryl sulfate and other amphipathic agents which enter cell membranes and increase their flexibility, low concentrations of hemolysin did not provide protection against hypotonic hemolysis. These findings indicate that the surface projections were not the result of membrane expansion caused by incorporation of hemolysin into the outer portion of the lipid bilayer. The ability of a given amount of hemolysin to release a constant amount of hemoglobin in the presence of increasing concentrations of red cells confirmed that a single hit is sufficient for lysis. These results suggest that a single hemolysin molecule can bind to a sheep erythrocyte and trigger internal reactions which result in the derangement of membrane integrity at multiple sites on the surface. Confirmation of one-hit kinetics indicates that measurement of E. coli hemolysin activity should be carried out at low ratios of hemolysin to erythrocyte to decrease the possibility of multiple hits on a single cell.

A 23-year-old primigravida was referred to our institute at 12 + 4 weeks' gestation with increased nuchal translucency (NT) thickness. Family history and the pregnancy to date were normal. On ultrasound examination using a Voluson E8 (GE Medical Systems, Zipf, Austria) equipped with a 3.5-5-MHz transabdominal probe, the crown-rump length was 71.3 mm and NT measured 2.5 mm. Echocardiography revealed both tricuspid valve and mitral valve insufficiency. A positive A-wave was observed in the ductus venosus on Doppler imaging. Neither pleural effusion nor ascites was found. Suspecting fetal anemia, we arranged for a serological examination of maternal blood which showed acute parvovirus infection (parvovirus B19 immunoglobulin (IgG) positive; IgG, 20 IU/mL; parvovirus B19 IgM positive; IgM index, 9.6).At 12 + 6 weeks' gestation there were signs of significant deterioration in the fetal condition with reversed flow in the ductus venosus during atrial contraction, the development of fetal hydrops and persistent atrioventricular (AV) valve insufficiency. At 13 + 0 weeks' gestation the fetus received an intracardiac transfusion of 1.5 mL irradiated red blood cell concentrate with increased hematocrit (blood group O rhesus negative) plus 0.5 mL of a platelet concentrate given through a 22-G needle.Three days after transfusion, positive flow in the A-wave of the ductus venosus was noted and the AV valve insufficiency showed signs of improvement. Generalized hydrops was no longer evident. The NT had increased to 4.4 mm. A second transfusion of 2 mL red blood cell concentrate and 1 mL platelet concentrate was given through the umbilical vein at the placental insertion. Blood sampling for red blood cell count proved impossible as the vein collapsed on aspiration.At 13 + 5 weeks' gestation, signs of deterioration (reversal of flow in the ductus venosus and an increase in NT to 5.6 mm) suggested a progression of fetal anemia. We therefore gave 2.5 mL red blood cells intravenously. Improvement was evident in both AV valves and in the ductus venosus waveform.There was renewed deterioration of flow in the ductus venosus at 14 + 4 weeks' gestation and fetal middle cerebral artery velocity was high at 35.0 cm/s 1 . Repeat transfusion was performed intravascularly with 2.5 mL red blood cell concentrate. NT thickness remained at 5.6 mm, and only the tricuspid valve still showed signs of insufficiency.At 15 + 6 weeks' gestation fetal middle cerebral artery velocity had increased to 39.5 cm/s. A fifth intravascular transfusion of 2.9 mL red blood cell concentrate was performed and the subsequent hemoglobin level was 12.0 g/dL.Follow-up ultrasound examinations showed normal fetal development. A small echogenic focus in the myocardium of the right ventricle that had been noted at the time of the first intracardiac transfusion persisted until birth. A small pericardial effusion documented after the first blood transfusion resolved completely by 17 weeks' gestation. Fetal magnetic resonance imaging at 28 + 5 weeks' gestation showed no evide...

Urinary bladders from mature cats, fixed in various degrees of distension, were studied with silver staining techniques under the light microscope, and with the electron microscope. Ganglia were located primarily in the adventitia, although small collections of perikaryons were located in nerves within the muscle coat. Large nerve trunks enclosed in perineural epithelium penetrated from the adventitia into the muscle coat, giving rise to smaller nerves which ran in the space between muscle fascicles. Small nerves entered each muscle fascicle, giving rise to final branches characterized by extreme tortuosity. There was less kinking and coiling of nerve fibers in bladders h e d in a more distended state. Encapsulated endings and myelinated fibers were scarce.Within a muscle fascicle, nerves were scant. Terminal branches intertwined among the individual smooth muscle cells as free nerve endings. Terminal axons continued to be ensheathed by Schwann cells. Neuromuscular synapses were characterizd by retraction of the Schwann cell from one side of the axon, presence of synaptic vesicles, and synaptic gaps of 400-600 A. Areas of close contact between flattened and interdigitating parts of adjacent smooth muscle cells were common. Membrane complexes of pinocytotic vesicles and endoplasmic reticulum were distributed around the periphery of individual smooth muscle cells. Smooth muscles cells appeared to vary in the density of their myofilament content.

We describe morphological sex differences in urinary bladders of the urodele amphibian Necturus maculosus. The mucosal epithelial cells of bladders from males were tall and contained considerable PAS-positive material. In scanning electron micrographs of the mucosal surface, epithelial cells from male bladders were well demarcated and were capped with microplicae or with long cilia. The mucosal epithelial cells of bladders from females were low and contained only a small amount of PAS-positive material; in scanning electron micrographs cell boundaries could not be distinguished and no cilia or microplicae were present. Bladders from males had higher transepithelial potential difference and lower water content than bladders from females. Urine analyses were not significantly different in the two sexes. It is suggested that response to androgens in the male accounts for the observed differences.

The ultrastructure of macrophages located in the dome of murine Peyer’s patches was examined by transmission electron microscopy. Aggregates of carbon particles as well as numerous other phagocytic and lysosomal inclusions were consistently observed in dome macrophages of carbon-fed mice. Macrophages of both particle-fed and control mice exhibited morphological features of activation. Degenerating macrophages were observed, and evidence is presented that their disintegration involves invasion by other cells. The morphological findings are in accordance with other evidence that the Peyer’s patches receive an influx of material from the intestinal lumen. The potential importance of macrophages in the initiation of intestinal inflammations is emphasized.

Thts repor t waa propn red as an acco unt of Give rome nt spon sored work . Nelth er the Unite d A. Make s any warra nty or repre senta llon, expre ssed or I mpli ed, wilh respe ct to the accu -/,cy, comp leten ess, or u//fu lnies of the infor matio n conta ined M this repo rt, or thal the use of any Worm alon. appa ratus , meth od, or proc ess diRc losed in Ws repo rt may not infrin ge priva tely own ed right a: or ' B. Assu mes any liabil lies /th resp ect to the use of, or for dima ge8 resu lUng from the I m of any infor etati on, Ippa ratw , meth od, or proc en discl osed in thls repo rt.As used in the abov e, "peri on actin g w beha lf of the Com misa ion" Ineu dee any em-1 ploy ee or con, racto r of the Com miss ion, or emp loye e of such cont ricto r, to the exte nt that Such emplo yee or Mtra ctor of the Com mies ion, or emp loyer of Buch cont racto r prep arM. disse mina tes, or prold es acce s, to, any Enfo rmalc n pursu ant to his empl oyme nt or contr act with the Com miHi on, or hti emp Zoym ent with auch cont racto r.

White Wrolstad turkeys were each inoculated with 100,000 Eimeria adenoides oocysts and killed on days 4-14 postinoculation. Tissue samples, obtained from 4 areas of the ceca comparable to areas examined in chickens infected with E. tenella in previous studies, were processed by a modification of the osmium-thiocarbo-hydrazide-osmium technique and examined with a scanning electron microscope. The pathologic situation found in turkeys was slightly different from that in the ceca of chickens infected with E. tenella. The mucosal lesions are most severe at the proximal end of an infected cecum. Surface disruption was far less severe than with cecal coccidiosis in chickens of the same age exposed to an equal number of infective oocysts. Rupture of the epithelial cell often caused the mucosal surface to present a honeycomb appearance. Some specific stages of the life cycle were identified, including schizonts and oocysts.

A group of chickens were inoculated with 100,000 Eimeria tenella oocysts each. The birds were sacrificed on days 4-14 postinoculation. Tissue samples from 4 different areas of each cecum examined were obtained and processed by the osmium-thiocarbohydrazide-osmium technique. Examination of the prepared tissues with the scanning electron microscope revealed lesions ranging from localized tissue swelling to complete disruption of the mucosal epithelium due to the rupture of large numbers of epithelial cells. The amount of damage to the tissue varied greatly, tending to be most obvious in the 2 more distal regions of the ceca examined. Observed in addition to the pathological changes demonstrated were some specific stages of the parasite, including schizonts, merozoites, and oocysts.