Search

It is possible to ion implant patterns in diamond crystals at fluences below that which would impart visible damage and then to reveal those patterns by electrostatic charging and dusting. The charge distribution — and therefore the dust attachement — is related to the difference in electrical conductivity between the implanted region and the rest of the crystal. The technique may have applicability for “fingerprinting” or personalizing diamond gemstones.

Using a simple technique based on electrostatic charging (essentially xerography of crystals), it has been found possible to reveal internal structure which appears to be directly related to that seen by other methods. It is necessary to expose the interior of the crystal in order to see the internal growth structure — i.e. to intersect the external growth surfaces since the latter are essentially homogeneous with respect to the electrostatic technique. If there are heterogeneities or discontinuities in the growth history of a crystal, we have found that the table, crown and pavilion facets of a cut stone are adequate intersecting planes for revealing patterns by the electrostatic technique. This technique might be the basis for a simple fingerprinting method for some gemstones.

A new series of heteroaromatic GBR 12935 [1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)piperazine] (1) and GBR 12909 [1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazine] (2) analogs was synthesized and evaluated as dopamine transporter (DAT) ligands. Analogs 5−16, in which the benzene ring in the phenylpropyl side chain of the GBR molecule had been replaced with a thiophene, furan, or pyridine ring, exhibited high affinity and selectivity for the DAT vs serotonin transporter (SERT) and stimulated locomotor activity in rats in a manner similar to the parent compound 2. In cocaine and food self-administration studies in rhesus monkeys, both thiophene-containing (6 and 8) and pyridine-containing (14 and 16) derivatives displayed potency comparable to 2 in decreasing the cocaine-maintained responding at the doses tested (0.3, 1.7, and 3 mg/kg). However, these compounds did not produce the degree of separation between food- and cocaine-maintained responding that was seen with 2. Among the bicyclic fused-ring congeners 17−38, the indole-containing analog of 2, 22, showed the greatest affinity for binding to the DAT, with IC50 = 0.7 nM, whereas the corresponding indole-containing derivative of 1, 21, displayed the highest selectivity (over 600-fold) at this site vs the SERT site.

The standard therapy for a pneumothorax of greater than 25 per cent is an intercostal tube thoracostomy. If this fails, a thoracotomy with stapling or suturing of any apical blebs and pleurodesis is indicated. The operation on patients with severe bullous disease consists of resection of bullae without removal of any other functional tissue. All efforts must be made to identify those patients with sufficiently good remaining lung tissue to make the operation most successful.

THE EVOLUTION of the total artificial heart (TAH) from animal experimentation to clinical research has necessitated major changes in the control of the drive equipment responsible for prosthesis function. Our experience with patients who have been permanent recipients of the heart has contributed to a refinement of the operating protocol and furthered understanding of the hemodynamic response to artificial circulation devices.PROSTHESIS DESIGNThe basic design of the pneumatic TAH has changed little since early animal experimentation and still incorporates a flexible diaphragm inside a semirigid housing.1-3 In the Jarvik-7-100 (Symbion, Inc, Salt Lake City) ventricles, which constitute the device under discussion herein, polyurethane polymer (Biomer, Ethicon Inc, Somerville, NJ) is molded with Dacron polyester mesh to form the semirigid housing. Four layers of Biomer each 0.18 mm in thickness constitute the inflatable diaphragm. Graphite powder between the diaphragm layers deters creation of a flexion crease, which could lead

A permanent total artificial heart, the Jarvik-7, was implanted into a 61-year-old male with a severe cardiomyopathy. Gated radionuclide studies were performed in the patient both prior to surgery and following implantation. Preoperative gated radionuclide cardiac studies revealed marked left ventricular enlargement, severe hypokinesis and a left ventricular ejection fraction of 10%. The right ventricle was moderately enlarged with a 27% ejection fraction. Following implantation of the Jarvik-7 artificial heart, gated cardiac studies were performed with a computer gated by a signal from the heart controller. The left ventricular ejection fraction was 69% and the right ventricular ejection fraction was 62%. This compared to a theoretical ejection fraction of 74% for each ventricle based on chamber anatomy. There was excellent ventricular emptying. Phase analysis showed uniform diaphragm motion. The use of gated cardiac studies in humans may prove helpful in evaluating mechanical problems with the artificial heart, such as malfunction of the diaphragm, before they become clinically apparent.

Bacterial infections are a significant complication of long-term total artificial heart implantation. We evaluated the functional capabilities of host defense mechanisms in two patients sustained long-term by a total artificial heart. Although serum complement and polymorphonuclear leukocyte function remained intact, both patients became B and T lymphopenic and there was an initial decrease in the ratio of helper/inducer to suppressor/cytotoxic cells. Histologic examination of their lymphoidal tissue at autopsy further revealed reduced numbers of germinal centers and atrophy of the T lymphocyte-dependent areas. In addition, the reticuloendothelial system was engorged with degenerate erythrocytes. We hypothesize that blockade of the reticuloendothelial system was induced by multiple blood transfusions necessitated by device-associated hemolysis and coagulopathy. This blockade may have led to a progressive loss of content of the antigen-specific lymphoidal elements and, perhaps, to a reduced ability to ingest microbe-antibody complexes.