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Biomedical subjects

M T Walsh

Publications and source records attributed to M T Walsh.

54 records · Page 3Linked to original sources
PubMed1987

Omphalitis and peritonitis in a young West Indian manatee (Trichechus manatus).

Mortality data for the West Indian manatee (Trichechus manatus) indicates that from 1979 to 1984 16% of the recorded deaths involved young juveniles. Necropsy of a young manatee from the west coast of Florida revealed an active infection of the umbilical area (omphalitis) extending down the umbilical artery and veins. A generalized peritonitis was present. Bacterial cultures revealed Streptococcus faecium, Plesiomonas shigelloides, Pseudomonas putrefaciens and Escherichia coli.

Animals↗
PubMed1986

Reassembly of low-density lipoproteins.

The methodologies described here for the selective and sequential reassembly of model LDL particles, although in many instances still in the developmental stages, will undoubtedly provide a basis on which further advances in LDL reassembly will be made. Reassembled LDL complexes of defined lipids and apoB provide well-defined model systems in which to study the molecular interactions and structural organization of LDL, including the lipid-lipid interactions in the particle core, the lipid-lipid and lipid-protein interactions which determine the surface organization and protein conformation, and the interactions between the core and surface components. These reassembled LDL complexes should serve as important models to study the delivery of isotopically labeled lipids with differing physical properties to cells in order to investigate the metabolic complexity of intracellular LDL catabolism and its relationship to positive cholesterol balance and atherogenesis.

Apolipoproteins B↗
PubMed1986

Physical properties of apoprotein B in mixed micelles with sodium deoxycholate and in a vesicle with dimyristoyl phosphatidylcholine.

Apoprotein B, the major apoprotein of normal human low density lipoprotein (LDL) was solubilized with sodium deoxycholate (NaDC). The protein was recombined with the phospholipid dimyristoyl phosphatidylcholine (DMPC) to produce a complex of DMPC-apoB (4:1 w/w). (Biochemistry. 22: 3170-3178. 1983). Carboxyfluorescein and [3H]dextran entrapment studies show the DMPC-apoB 4:1 (w/w) complex to encapsulate an aqueous volume of 0.17 microliter/mumol of DMPC. From the chemistry and morphology of the complex and the evidence that the complex possesses an encapsulated volume, the most appropriate structural model for this assembly is that of a phospholipid single bilayer vesicle into which apoB is incorporated. Differential scanning calorimetry (DSC) and circular dichroic spectroscopy (CD) were used to investigate the physical properties of apoB in the mixed micellar complex with NaDC and in the vesicular DMPC-apoB complex. CD studies of apoB in NaDC mixed micelles show that apoB exhibits a similar secondary structure as apoB of native LDL over the temperature range 5-30 degrees C. Reversible structural changes occur between 30 and 50 degrees C. However, above 50 degrees C, disruption of the micellar particle and endothermic protein unfolding and denaturation occur with a Tmax of 52 degrees C and an enthalpy of 0.22 cal/g apoB, as shown by DSC. The DMPC-apoB complex exhibits a reversible thermal transition centered at 24 degrees C (delta H = 3.34 Kcal/mol DMPC) which is associated with the order-disorder transition of the hydrocarbon chains of DMPC. An endothermic transition occurs over the range 53-70 degrees C (delta H = 2.09 cal/g apoB) which, as shown by CD and turbidity study, corresponds to protein unfolding-denaturation and particle disruption. CD shows that apoB in the vesicular environment undergoes a series of conformational changes. The major alterations occur over the temperature range of the order-disorder transition of the phospholipid. Between 37-60 degrees C, the conformation is similar to that observed in native LDL.

Apolipoproteins B↗
PubMed1985

Effect of exogenous ACTH on serum corticosterone and cortisol concentrations in the Moluccan cockatoo (Cacatua moluccensis).

The effects of exogenous adrenocorticortrophic hormone (ACTH) on the serum corticosterone and cortisol concentrations were determined in 28 mature Moluccan cockatoos (Cacatua moluccensis), a representative of the psittacine species. Birds were randomly assigned to 4 groups (2 ACTH-treated groups and 2 saline-treated controls). Group I (10 cockatoos [5 males and 5 females] ) was given 15 IU of ACTH after blood samples (base line) were taken at 10:00 AM. Blood samples were taken again at 30 minutes and 2.5 hours after ACTH administration. Group II (10 cockatoos) was given similar treatment, but blood samples were taken at 1 and 4 hours after ACTH was administered. Groups III and IV (each of 4 birds) were given saline solution injections as controls. Blood samples were taken at 30 minutes and 2.5 hours after injection (group III) and at 1 and 4 hours after injection (group IV). All serum samples were analyzed for cortisol and corticosterone. Serum corticosterone concentration increased significantly (P less than 0.01) from base-line levels (26 ng/ml) to 108 ng/ml within 30 minutes after ACTH was administered. The high values were maintained for 3 hours and then decreased to 40 ng/ml at the end of 4 hours. Male birds seemed to respond to the ACTH treatment quickly and maintained increased concentration for a shorter period when compared with the responses seen in female birds. Serum cortisol values remained low throughout the experimental period. These results indicate that serum corticosterone was responsive to ACTH administration, but cortisol was not. In addition, there may be a difference in the responses between male and female members of the species.

Adrenal Glands↗
PubMed1984

Reassembled plasma low density lipoproteins. Phospholipid-cholesterol ester-apoprotein B complexes.

Reassembled low density lipoprotein (LDL) complexes have been prepared by the interaction of lipid-free sodium deoxycholate-solubilized apoprotein B (apoB) of native human LDL with preformed, 200 A in diameter, microemulsions of cholesteryl oleate (CO), surface-stabilized by either egg yolk phosphatidylcholine ( EYPC ) or dimyristoyl phosphatidylcholine (DMPC). Gel chromatography of PC/CO/apoB complexes shows co-elution of the complex at 43% PC, 43% CO, and 14% apoB. Negative stain electron microscopy shows the particles to be circular, homogeneous, and approximately 200 A in diameter. PC/CO/apoB complexes exhibit beta-migration on agarose gels and show one high molecular weight protein band on 3.0% sodium dodecyl sulfate-polyacrylamide gels. Differential scanning calorimetry and x-ray scattering show the lipids in the complexes to undergo at least two specific thermal transitions depending on lipid composition, one associated with the core-located cholesterol esters similar to LDL and the protein-free microemulsions and the other from the phospholipid forming the surface monolayer. In addition, particle disruption-protein unfolding/denaturation occur irreversibly at 80-85 degrees C. At 4 degrees C, the secondary structure of apoB on complexes of EYPC /CO/apoB is similar to that of native LDL. For complexes of DMPC/CO/apoB, the secondary structure shows less alpha-helix which correlates with the difference in surface lipid environment. The reassembled complexes of PC/CO/apoB provide a defined system in which the components may be varied systematically in order to study the molecular organization, molecular interactions, and metabolism of LDL.

Apolipoproteins↗
PubMed1984

New horizons: the changing world of television.

These are just some of the new opportunities that television is opening up for nonprofits. I should mention that, there are also certain other implications, such as the fracturing of the mass TV audience into more fragmented markets. This means that nonprofit organizations will have to produce more PSA's to reach its audience. There'll also be more competition for available public service time. Finally, as pay TV grows, nonprofit organizations may have to produce special programming for this medium. There's several things we can comfortably predict for the future. One, television will continue to change. And two, the successful nonprofit organizations will be those who seriously explore the new opportunities today.

Organizations, Nonprofit↗
PubMed1983

Solubilization of low-density lipoprotein with sodium deoxycholate and recombination of apoprotein B with dimyristoylphosphatidylcholine.

Apoprotein B (apoB) of human plasma low-density lipoprotein (LDL) (d 1.025-1.050 g/mL) has been solubilized with solid sodium deoxycholate (NaDC) above its critical micellar concentration. ApoB is isolated by gel-filtration chromatography as a mixed micellar complex of protein and detergent in high yield in a lipid-free form. A soluble apoB-dimyristoylphosphatidylcholine (DMPC) complex has been prepared by incubation of aqueous solutions of apoB-NaDC and DMPC-NaDC (2/1 w/w) at room temperature with detergent removal by extensive dialysis. A combination of gel chromatographic and density gradient fractionation of DMPC-apoB incubation mixtures demonstrates that a reasonably well-defined complex of DMPC and apoB is formed with a 4:1 w/w lipid:protein ratio. Negative-stain electron microscopy shows these particles to be single-bilayer phospholipid vesicles with a diameter of 210 +/- 20 A into which the apoB is incorporated. Circular dichroic spectra of NaDC-solubilized apoB show apoB to have similar conformation to that seen in the native LDL particle. However, apoB that has been complexed with DMPC exhibits more alpha-helix. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis shows a single band (apparent Mr 366000) for apoB after solubilization, purification, and interaction with phospholipid. The behavior of apoB during its reassociation with phospholipid and the structural features of the DMPC-apoB particle are similar to those observed in the interaction of solubilized membrane proteins with lipid rather than that of other apo-lipoproteins.

Apolipoproteins↗
PubMedDate not supplied

Anesthesia for pediatric laparoscopic cholecystectomy.

We report the general anesthetic events and clinical concerns encountered with a laparoscopic cholecystectomy in a 19-month-old toddler. Carbon dioxide was insufflated to create a pneumoperitoneum, with resulting intra-abdominal pressures ranging from 5 to 11 mmHg. The end-tidal partial pressure of carbon dioxide (PETCO2) rose as high as 48 mmHg (a 10 mmHg increase from baseline), requiring a 68% increase in minute ventilation to achieve preinsufflation values. Careful monitoring of ventilation, PETCO2, and intra-abdominal pressure are recommended for optimal anesthetic management of the pediatric laparoscopic cholecystectomy patient.

Anesthesia, Inhalation↗
PubMedDate not supplied

Therapist management of thoracic outlet syndrome.

Treatment of the thoracic outlet patient can be a complex and challenging problem for the occupational or physical therapist. The literature supports conservative care as the preferred approach for these patients; therefore, therapy plays an important role in caring for these patients. I question whether TOS is becoming the RDS of the 1990s. Often these "TOS" patients are suffering from additional secondary system complaints including active myofascial trigger points, primary or secondary glenohumeral joint pathologies, cervical pathology, or more distal peripheral neuropathies. A thorough evaluation by the therapist is extremely important in determining TOS and separating compressive TOS from entrapment TOS. It is only after a thorough assessment that a proper treatment approach can be formulated. Treatment should initially address comfort, control, and relief and then progress to the neurovascular component. Finally, strengthening and conditioning, if tolerated, are implemented. Properly educating the patient to achieve behavior modification, exercise compliance, symptom control, and postural correction is requisite to optimal results.

Adult↗
PubMedDate not supplied

Early controlled motion with dynamic splinting versus static splinting for zones III and IV extensor tendon lacerations: a preliminary report.

Recent developments in the understanding of tendon healing and the effects of early motion have led to early controlled motion programs (ECM) for lacerated extensor tendons. The purpose of this study was to determine whether there were differences in length of treatment and final results when patients who had been treated with ECM with dynamic splinting were compared with patients who had been treated with traditional static extension splinting (SES) for zone III and zone IV extensor tendon lacerations. A retrospective study of patient charts from June 1984 through January 1990 was conducted. A total of 36 charts were reviewed. Twenty-seven patients met the study criteria: treatment with ECM with dynamic splinting (n = 10) and treatment with traditional SES using a finger-hand splint (n = 17). Data were analyzed for total number of therapy visits (V), total number of weeks of therapy before discharge (W), total active motion achieved (TAM), total passive motion achieved (TPM), and incidence of complications. Significance was established at the p = 0.05 level for all statistical analyses. There were no significant differences between the groups for V (t = 1.76, p = 0.09), W (t = 0.58, p = 0.57), TPM (t = 0.12, p = 0.90), TAM (t = 0.44, p = 0.66), or the incidence of extensor lag (chi 2 = 2.264). The Cohen stat power analysis value was 0.40, revealing that the number of patients was too small for significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗