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Biomedical subjects

L Gould

Publications and source records attributed to L Gould.

At least 37 records · Page 2Linked to original sources

Depot drug delivery system for 5-fluorouracil after filtration surgery in the rabbit.

We investigated the potential value of 50:50 poly (DL glycolic acid-lactic acid) (PGLA) copolymer as a degradable depot delivery system for 5-fluorouracil (5-FU) after filtration surgery. Analysis of retrieved discs after implantation in 22 eyes of 22 pigmented rabbits showed a dual drug release profile and polymer mass loss characteristics. In a second group of pigmented rabbits implantation of PGLA discs impregnated with 5-FU (22 eyes) significantly lengthened the survival time of filtration fistulae compared with discs without 5-FU (18 eyes) or no disc (10 eyes) (p < 0.0001). Use of PGLA copolymer impregnated with 5-FU could prove valuable for patients undergoing glaucoma filtering surgery.

Animals↗

Fifty:fifty poly (DL glycolic acid-lactic acid) copolymer as a drug delivery system for 5-fluorouracil: a histopathological evaluation.

Fifty:fifty poly (DL glycolic acid-lactic acid) copolymer (PGLA) is a potentially useful depot drug delivery system for 5-fluorouracil (5-FU). The purpose of this study was to evaluate the fibroinflammatory reaction induced by this polymer. Polymer discs without 5-FU were inserted subconjunctivally in one eye of each of two guinea pigs and four pigmented rabbits (control group), and discs containing 20% 5-FU were inserted subconjunctivally in both eyes of nine pigmented rabbits (study group). The tissue reaction to the copolymer did not differ between rabbits and guinea pigs, with a mild mixed inflammatory reaction 1 week after implantation. At 2 weeks a thin fibrous capsule surrounded the discs, with no change in the amount of inflammation. At 4 weeks the disc had disintegrated, but residual polymer was seen within multinucleated giant cells in the episcleral tissue. Granulation tissue and inflammatory responses were mild. Less inflammation and fibrosis occurred in the study eyes, although the pattern of response was similar in the two groups. The inflammatory response to PGLA was markedly less than that to implanted collagen shields, and our findings suggest that PGLA implant is a promising ocular drug delivery system for 5-FU after filtration surgery.

Animals↗

Radionuclide simultaneous dual-isotope stress myocardial perfusion study using the "three window technique".

Several methods are available for performing radionuclide stress myocardial perfusion studies. All of these methods require two separate acquisition and processing iterations, which is time-consuming and inconvenient for the patient. The authors introduce a new method using the "three window technique" that they developed to perform simultaneous dual-isotope imaging for stress myocardial perfusion studies. In addition to Tl-201 and Tc-99m windows centered at 70 KeV and 140 KeV, respectively, a third window centered at 105 KeV, representing scattered radioactivity from Tc-99m, is established. By subtracting the radioactivity in the third window from the radioactivity in the Tl-201 window, "crosstalk" interference is significantly reduced. The simultaneous dual-isotope imaging method acquires and processes resting and stress myocardial perfusion images simultaneously. It halves imaging time and doubles patient throughput, improves scheduling flexibility, and reduces patient waiting time and discomfort.

Heart↗

Introduction of human genomic sequences renders CHO-K1 cells susceptible to infection by amphotropic retroviruses.

To learn more about the nature of the block to infection by amphotropic retroviruses exhibited by Chinese hamster cells (CHO-K1), CHO-K1 cells were made susceptible to amphotropic retrovirus infection by introducing genomic DNA from infectable human cells. A clone, designated CHO18, was obtained and shown to be infected as efficiently as NIH 3T3 fibroblasts. Susceptibility of CHO18 cells to infection was specific to retroviruses and vectors bearing an amphotropic envelope. By comparison to CHO-K1 cells, CHO18 cells may provide a useful model for analysis of the molecular events involved in the retrovirus-receptor interaction.

3T3 Cells↗

Use of i.v. radionuclide total body arteriography to evaluate arterial bypass shunts--a new method--a review of several cases.

Currently, Doppler ultrasound and contrast angiography are the main imaging procedures being used to evaluate arterial bypass shunts. IV radionuclide total body arteriography (TBA) is another useful imaging procedure for evaluation of bypass shunts. The authors reviewed 33 patients, 19 women and 14 men, ranging in age from forty-three to eighty-five, who had TBA done after arterial bypass surgery. Ten patients had multiple shunts and 5 had multiple follow-up studies. In total there were 80 shunts, including 43 femoropopliteal, 16 axillofemoral, 1 axillopopliteal, 13 crossover femorofemoral, and 7 aortofemoral shunts. Sixty-two of the 80 shunts were patent, 14 were occluded, and 4 had partial occlusion. The results were confirmed by Doppler studies, contrast angiograms, and/or surgical exploration without false positives or false negatives. Since the radiotracer used was 99mTc-labeled red blood cells, a MUGA study can also be performed immediately following TBA in the same injection. Twenty-eight patients had gated cardiac blood pool studies (MUGA) done; 16 had abnormal wall motion and diminished ventricular function. TBA requires only a single IV injection of radiotracer (less than 1 cc) in the upper limb. The imaging times for total body arterial and perfusion images are seventy seconds and five minutes respectively. Both total body arterial and perfusion images clearly demonstrated the entire course of shunts (single or multiple); underlying and coexisting arterial abnormalities, e g, occlusive disease (27 patients), or aneurysm (3 patients); and related perfusion changes in the extremities. TBA has unique features. It permits a complete, excellent visualization of the bypass graft without the hazard of contrast media injection. It is a simple and a virtually noninvasive procedure, particularly useful for preoperative workups and postoperative follow-ups.

Adult↗

Effects of two cocktails on left ventricular diastolic function in normal men.

The effects of alcohol on diastolic function in normal males are unknown. Therefore, 12 male physicians had a Doppler echocardiogram performed in order to assess left ventricular diastolic performance. They then drank 4 ounces of whiskey, and forty-five minutes later a repeat Doppler echocardiogram was obtained. All the Doppler indexes of diastolic performance differed significantly after the ingestion of alcohol. The mean control D-F interval was 203 +/- 26 ms and after alcohol it was 237 +/- 51 (p less than 0.01). The mean control EF slope was 4.4 +/- 0.35 m/s2 and after alcohol it was 3.2 +/- 0.73 (p less than 0.01). The control E-F interval was 114 +/- 30 ms and it increased after alcohol to 150 +/- 37 (p less than 0.001). The mean control E wave was 0.54 +/- 0.10 m/s and after alcohol it was 0.43 +/- 0.07 (p less than 0.01). The mean control A wave was 0.30 +/- 0.04 m/s and after alcohol it was 0.35 +/- 0.04 (p less than 0.01). The mean control E/A ratio was 1.80 +/- 0.20 and it fell to 1.25 +/- 0.23 after alcohol ingestion (p less than 0.001). Thus, the results suggest that 4 ounces of whiskey can produce, in normal males, a significant impairment in diastolic function.

Adult↗

Pulse generator failure due to blunt trauma.

This case describes a 69-year-old male who had a permanent pacemaker implanted for sick sinus syndrome. He was struck by a car with a resultant failure of the pulse generator. Trauma-related failure of a pulse generator is a rare event. Its recognition is imperative in the overall management of the trauma patient.

Accidents, Traffic↗

Effects of acute alcohol intoxication on cerebral blood flow measured with PET.

Regional distribution of cerebral blood flow was assessed in a group of 13 normal social drinkers under baseline conditions and after acute alcohol intoxication. Blood flow measurements were done using 15O-labeled water and positron emission tomography (PET). Each subject underwent two control sessions under baseline conditions and two sessions after alcohol. Seven of the subjects were given 0.5 g/kg of alcohol and six were given 1 g/kg of alcohol p.o. The first and second post-alcohol scans were done 40 and 60 min after alcohol ingestion. The studies revealed that both the high and the low doses of alcohol reduced blood flow to the cerebellum. This effect was significant only for the high doses of alcohol, which also increased blood flow to the right temporal and the prefrontal cortex. The decrease in blood flow of the cerebellum could account for the muscular incoordination induced by alcohol.

Adult↗

Intravenous radionuclide total body arteriography: a new technique.

We have developed a technique using a blood pool agent Tc-99m labeled red blood cells and a detector head set moving at a high speed to obtain total body arterial and blood pool images with only a single intravenous injection. Previously with an intravenous radiotracer injection, only regional arterial images could be obtained. Now, with this simple, non-invasive technique, we can evaluate the major arterial system, organs, and soft tissues in the whole body, as well as cardiac function. On reviewing 500 cases, more than 90% of the first-pass arterial phase images clearly demonstrated the aorta, ilio-femoral arteries, and, to a lesser extent, the more distal arteries in the lower extremities. The second-pass blood pool images revealed the anatomical and morphological status of the solid organs, as well as perfusion changes in various organs and soft tissues.

Adult↗

IV radionuclide total-body arteriography: a new noninvasive whole-body screening procedure--a case report.

Recently the authors introduced a new technique of intravenous (IV) radionuclide total-body arteriography. The major arterial system, multiple organs of the whole body, and cardiac function can be evaluated with one small IV injection in the arm. After analyzing more than 1000 cases, they have found that many pathologies can be detected and/or confirmed in this procedure. This new technique may be used as a general whole-body screening test for those patients at high risk for disease.

Aged↗

Routine reduction of pulse generator voltage.

The porous-tip electrode has led to a significant advancement in pacing system technology. Experience with 38 patients with unipolar tined CPI porous endocardial electrodes, is reported. All patients had programmable pulse generators, CPI model number 531. The voltage in this pulse generator can be reduced from 5 to 2.5 volts. The pulse width threshold (PWT) at implantation was 0.06 ms at 5 volts in all 38 patients, and the PWT at implantation varied between 0.06 and 0.16 ms at 2.5 volts, with a mean PWT of 0.092 +/- 0.026 ms. The 38 patients were restudied six months later. The mean PWT measured at 5 volts was 0.076 +/- 0.018 ms. The PWT measured at 2.5 volts varied between 0.08 and 0.30 ms with a mean PWT of 0.178 +/- 0.067 ms. Twenty-three patients were restudied one year after lead implantation. The PWT measured at 2.5 volts varied between 0.08 and 0.30 ms with a mean PWT of 0.156 +/- 0.061 ms. All of the pulse generators were reprogrammed to 2.5 volts. This permitted a substantial prolongation of the pulse generator life (three to five years) with an improvement in the cost effectiveness of the pulse generator.

Electrodes↗

Cerebral involvement in systemic lupus erythematosus.

Four patients with central nervous system lupus erythematosus (SLE), were studied with nuclear magnetic resonance imaging (NMRI) and positron emission tomography (PET) to assess cerebral blood flow and glucose metabolism. The NMRI showed brain atrophy and demyelinating defects. The PET scan showed cerebral blood flow and metabolic abnormalities that improved in one patient after neuropsychiatric recovery. These preliminary findings demonstrate cerebral derangements in patients with SLE cerebritis.

Adult↗