The purification and characterization of a phospholipase A in hamster heart cytosol for the hydrolysis of phosphatidylcholine

Phospholipases A1 and A2 catalyze the hydrolysis of acyl groups of phospholipids at C-1 and C-2, respectively. These phospholipases are important in phospholipid catabolism and the remodeling of the acyl groups of phospholipids. Phospholipase A from hamster heart cytosol was purified by a combination of ion-exchange and gel filtration chromatography. The purity of the enzyme was assessed by nondenaturing polyacrylamide gel electrophoresis, two-dimension polyacrylamide gel electrophoresis, and immunological studies. The purified enzyme exhibited both phospholipase A1 and A2 activities toward phosphatidylcholine and had the ability to hydrolyze the acyl groups of phosphatidylethanolamine. However, the enzyme was not active toward lysophosphatidylcholine, diacylglycerol, or triacylglycerol. By Sepharose 6B chromatography, the molecular weight of the purified enzyme was estimated to be 140,000. Analysis of the purified enzyme by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the enzyme was composed of identical Mr 14,000 subunits. At least six subunits in the native enzyme could be cross-linked by dimethyl suberimidate. Both phospholipase A1 and A2 activities showed similar pH profiles, exhibited no absolute requirements for divalent metallic cations, but displayed a high degree of specificity for the acyl groups of phosphatidylcholine at both C-1 and C-2. The Km of phospholipases A1 and A2 for 1-palmitoyl-2-arachidon-ylglycerophosphocholine was found to be identical (0.5 mM).

Amniotic band sequence and its neurocutaneous manifestations

Six new cases of the amniotic band sequence with a wide spectrum of defects were studied with respect to neurocutaneous manifestations, including histopathologic characteristics. Fetuses 1 and 2 were stillborn. Despite severe craniofacial involvement, infants 3 and 4 survived 1 yr and 22 months, respectively. Patients 5 and 6 had only limb defects. Craniofacial and neurologic manifestations of our longer-survival patients with severe craniofacial anomalies were microcephaly, encephalocele, micro- or anophthalmia, mental retardation, hydrocephaly, seizures, EEG abnormalities, impaired body temperature control, impaired vision, hypertonia, and other psychomotor deficits. Characteristic cutaneous manifestations seen in our patients were clefting, schisis, fibrous strings, ring constriction, lymphedema. pseudosyndactyly, and intrauterine amputation. Histologic examination of the amniotic bands attaching to the skin showed autolyzed amnion in patient 2, erosion of the band into upper dermis in patient 1, and fibrosis underlying the constricted areas in patient 5. Prenatal diagnosis by ultrasonography is possible in patients with severe craniofacial defects (patient 2). A brief review of the literature is offered.

Venous bridge used in free flap transfer for the lower leg in the presence of venous hypertension: a case report

Reconstruction with free flaps for the lower leg in the presence of venous thrombosis or venous hypertension has a high risk of failure. We describe the use of the contralateral leg for venous drainage through a pedicled skin bridge containing a tributary of the long saphenous vein. The recipient artery was a main artery of the ipsilateral leg. Two weeks later, once there was a well-established venous communication between flap and recipient site, the venous bridge was divided. Because the arterial inflow to the flap was not interrupted by the division of the skin bridge, the flap has good viability and good resistance to infection or ulceration 3 years later.

Design of a holographic lens for the infrared

Techniques are described for the construction of a holographic lens for focusing a collimated beam to a point. The lens is constructed in the visible for use in the near infrared. A major problem is to eliminate aberrations that result from the shift between the wavelength of construction and of use.

Stab wounds to the abdomen: failure of blunt probing to predict peritoneal penetration

A study was conducted to examine the usefulness of blunt probing for evaluation of penetrating abdominal trauma. Ten anesthetized adult beagles weighing 8 to 17 kg were sacrificed by ventricular fibrillation following a standardized resuscitation protocol. Immediately thereafter, the abdomen was shaved and ten stab wounds were placed in the abdomen of each dog with #11 blade. A separate individual probed the wounds sequentially with a cotton swab and predicted on the basis of this examination whether the wound penetrated the parietal peritoneum (deep) or not (superficial). The abdomen then was opened and reflected, by a midline incision, and peritoneal penetration was verified visually by two observers. Statistical analysis of data was performed using the z test for binomial proportions. Fifty-nine of the 100 wounds were found to penetrate the parietal peritoneum. Examiners predicted 35 correctly, but called 24 of 59 superficial. Thirty-eight of 41 superficial wounds were identified correctly; three were incorrectly called deep. Sensitivity was .59 (z = 1.432, P greater than .5); specificity was .93 (z = 5.466, P less than .001). Blunt probing may be a useful technique if peritoneal penetration is determined, but it is inaccurate in predicting peritoneal nonpenetration. If violation of the peritoneum is not determined with this technique, other methods must be used.

Nitrogen fixation ability of exopolysaccharide synthesis mutants of Rhizobium sp. strain NGR234 and Rhizobium trifolii is restored by the addition of homologous exopolysaccharides

Several transposon Tn5-induced mutants of the broad-host-range Rhizobium sp. strain NGR234 produce little or no detectable acidic exopolysaccharide (EPS) and are unable to induce nitrogen-fixing nodules on Leucaena leucocephala var. Peru or siratro plants. The ability of these Exo- mutants to induce functioning nodules on Leucaena plants was restored by coinoculation with a Sym plasmid-cured (Nod- Exo+) derivative of parent strain NGR234, purified EPS from the parent strain, or the oligosaccharide from the EPS. Coinoculation with EPS or related oligosaccharide also resulted in formation of nitrogen-fixing nodules on siratro plants. In addition, an Exo- mutant (ANU437) of Rhizobium trifolii ANU794 was able to form nitrogen-fixing nodules on white clover in the presence of added EPS or related oligosaccharide from R. trifolii ANU843. These results demonstrate that the absence of Rhizobium EPSs can result in failure of effective symbiosis with both temperate and subtropical legumes.

Three conditions in neonatal asphyxiating thoracic dysplasia (Jeune) and short rib-polydactyly syndrome spectrum: a clinicopathologic study

Clinicopathologic examination of eight patients with asphyxiating thoracic dysplasia (Jeune; ATD) disclosed two different types, which were designated as type 1 and type 2. Type 1 ATD was characterized by the presence of radiologically irregular metaphyseal ends and histopathologically irregular cartilage bone junction with patchy distribution of physeal zone of hypertrophy. Type 2 ATD showed radiologically smooth metaphyseal ends and histopathologically diffusely retarded and disorganized physes with smooth cartilage bone junctions. Examination of four patients with the "Verma-Naumoff" short rib-polydactyly syndrome showed many radiologic and pathologic features similar to those of type 1 ATD. Differential diagnosis of these three osteochondrodysplasias is discussed along with chondroectodermal dysplasia (Ellis-van Creveld), short rib-polydactyly syndrome type 1 (Saldino-Noonan), short rib-polydactyly syndrome type 2 (Majewski), and the new short rib syndrome reported by Beemer et al [1983].

The inhibitory effects of some adenosine analogues on transmitter release at the mammalian neuromuscular junction

An electrophysiological study was made of the effects of four adenosine analogues, 2-chloroadenosine (2-CIA), 5'-N-ethylcarboxamidoadenosine (NECA), L-N6-phenylisopropyladenosine (L-PIA), and 2-(p-methoxyphenyl)-adenosine (CV-1674) on neurotransmitter release in the mouse phrenic nerve - hemidiaphragm preparation. All four drugs decreased miniature end-plate potential frequency in a dose-dependent manner. Evoked transmitter release in the cut diaphragm preparation was depressed by 2-CIA and CV-1674 to a similar extent. The ability of theophylline to antagonize the inhibitory effect of CV-1674 on spontaneous transmitter release was also established. On the basis of these results, the rank order of potencies was: L-PIA greater than NECA greater than 2-CIA greater than CV-1674. A clear classification of receptor type could not be made, since the ratio of potencies of L-PIA and NECA was narrow. Different slopes of the concentration-effect curves for 2-CIA and CV-1674 compared with L-PIA and NECA suggest an additional component to simple agonist action in their overall effects.

Coverage of the degloved thumb with twin neurovascular island flaps: a case report

A simple and useful method is described for resurfacing a distal phalanx of the degloved thumb with twin neurovascular island flaps from the ulnar and radial aspects of the middle and ring fingers respectively. It provides protective sensation and an acceptable cosmetic result.