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Biomedical subjects

D M Mulvihill

Publications and source records attributed to D M Mulvihill.

16 recordsLinked to original sources
PubMed2001

Development and application of confocal scanning laser microscopy methods for studying the distribution of fat and protein in selected dairy products.

Confocal scanning laser microscopy (CSLM) methods were developed to identify fat and protein in cheeses milk chocolate and milk powders. Various fluorescent probes were assessed for their ability to label fat or protein in selected food products in situ. Dual labelling of fat and protein was made possible by using mixtures of probes. Selected probes and probe mixtures were then used to study (a) structure development of Mozzarella cheese during manufacture and ripening, and (b)) the distribution of fat and protein in milk chocolate made with milk powders containing varying levels of free fat. Microstructural changes in the protein and fat phases of Mozzarella cheese were observed at each major step in processing. Aggregation of renneted micelles occurred during curd formation; this was followed by amalgamation of the para-casein into linear fibres during plasticization. Following storage, the protein phase of the Mozzarella became more continuous; entrapping and isolating fat globules. Chocolate made with a high free-fat spray-dried powder blend showed a homogeneous fat distribution, similar to that of chocolate made with roller-dried milk. Chocolate made with whole milk powder containing 10 g free fat/100 fat showed a non-homogeneous fat distribution with some fat occluded within milk protein particles. These differences in fat distribution were related to Casson yield value and Casson viscosity of the chocolates.

Animals↗
PubMed2001

Direct in situ viability assessment of bacteria in probiotic dairy products using viability staining in conjunction with confocal scanning laser microscopy.

The viability of the human probiotic strains Lactobacillus paracasei NFBC 338 and Bifidobacterium sp. strain UCC 35612 in reconstituted skim milk was assessed by confocal scanning laser microscopy using the LIVE/DEAD BacLight viability stain. The technique was rapid (<30 min) and clearly differentiated live from heat-killed bacteria. The microscopic enumeration of various proportions of viable to heat-killed bacteria was then compared with conventional plating on nutrient agar. Direct microscopic enumeration of bacteria indicated that plate counting led to an underestimation of bacterial numbers, which was most likely related to clumping. Similarly, LIVE/DEAD BacLight staining yielded bacterial counts that were higher than cell numbers obtained by plate counting (CFU) in milk and fermented milk. These results indicate the value of the microscopic approach for rapid viability testing of such probiotic products. In contrast, the numbers obtained by direct microscopic counting for Cheddar cheese and spray-dried probiotic milk powder were lower than those obtained by plate counting. These results highlight the limitations of LIVE/DEAD BacLight staining and the need to optimize the technique for different strain-product combinations. The minimum detection limit for in situ viability staining in conjunction with confocal scanning laser microscopy enumeration was approximately 10(8) bacteria/ml (equivalent to approximately 10(7) CFU/ml), based on Bifidobacterium sp. strain UCC 35612 counts in maximum-recovery diluent.

Animals↗
PubMed1999

Persistent pulmonary hypertension in a neonate with cystic adenomatoid malformation of the lung following lobectomy: survival with prolonged extracorporeal membrane oxygenation therapy.

A full-term neonate is reported with congenital cystic adenomatoid malformation of the lung treated by lobectomy with development of pulmonary hypertension. The infant was successfully treated with extracorporeal membrane oxygenation (ECMO) for persistent pulmonary hypertension, which developed postoperatively. An 18-day course of venovenous ECMO was necessary to effectively reverse the severe pulmonary hypertension. This was probably a result of significant pulmonary hypoplasia of the compressed lung. Although not all congenital cystic adenomatoid malformations of the lung are associated with pulmonary hypoplasia and persistent pulmonary hypertension, this is one case where severe pulmonary hypertension developed secondary to a mass effect by a large lesion in the chest.

Cystic Adenomatoid Malformation of Lung, Congenita↗
PubMed1998

Hyperventilation impairs oxygenation after bidirectional superior cavopulmonary connection.

BACKGROUND: Bidirectional superior cavopulmonary connection (BSCC) may be complicated by systemic hypoxemia. Hyperventilation, which is standard therapy for postoperative hypoxemia, has opposing effects on the pulmonary and cerebral vascular beds, which are connected after BSCC. It is unknown which of these effects predominates and, therefore, whether hyperventilation improves or impairs systemic oxygenation after BSCC. METHODS AND RESULTS: Twelve consecutive patients (median age, 6.4 months; age range, 6.0 to 32.0, months) undergoing BSCC were studied prospectively. Patients were studied in the intensive care unit within 6 hours of surgery and while sedated, paralyzed, and mechanically ventilated. Inotropes were not altered, and no transfusions were given. FIO2 was set at 100%, and peak end-expiratory pressure was set at 0. Each patient was studied first during normal ventilation, then during hyperventilation, and finally again during normal ventilation. Hyperventilation resulted in significant decreases in arterial PO2, systemic oxygen saturation, and transpulmonary gradient. Cerebral blood flow velocity was measured in 6 patients through transcranial Doppler sonography of the middle cerebral artery. Mean cerebral flow velocity decreased significantly during hyperventilation. CONCLUSIONS: Hyperventilation significantly impairs systemic oxygenation after BSCC. This fall in oxygenation occurs despite a decrease in transpulmonary gradient. A possible mechanism for this effect is that hyperventilation lowers arterial PCO2, raising cerebral vascular resistance, and lowering cerebral, superior vena caval, and pulmonary blood flows. Supportive evidence for this mechanism is the decrease in cerebral flow velocity that occurs during hyperventilation. After BSCC, normal ventilation rather than hyperventilation should be used to improve systemic oxygen levels.

Adolescent↗
PubMed1995

MR of cystic aberrant cervical thymus.

The clinical, MR imaging, surgical, and histologic findings in two cases of cystic aberrant cervical thymus were reviewed. Aberrant cervical thymic tissue was sharply circumscribed and extended deep to the posterior pharyngeal wall at the level of the piriform sinus in both cases. Both lesions had cyst contents that were of increased signal intensity on T1-weighted images. Solid components displayed MR signal characteristics identical to normal thymus.

Child↗
PubMed1993

A common presentation of an uncommon cause of neonatal respiratory distress: pneumonia alba.

While lung involvement is an uncommon presentation of congenital syphilis, respiratory distress is a common leading symptom in sick newborns. We describe an infant who presented with respiratory distress thought to be secondary to congenital syphilis and discuss the findings suggestive of an etiology other than respiratory distress syndrome (RDS).

Diagnosis, Differential↗
PubMed1990

A model of Staphylococcus aureus bacteremia, septic arthritis, and osteomyelitis in chickens.

We studied the occurrence, magnitude, and kinetics of bacteremia and the resultant osteomyelitis and septic arthritis in an avian model of Staphylococcus aureus infection. Thirty-day-old male broiler chicks were inoculated i.v. with 10(5), 10(6), or 10(7) cfu of strain Duntravis, a beta-hemolytic, coagulase-producing, capsular type 8 isolate from the synovial fluid of a 2-year-old black boy. Bacteremia occurred in 80%, 90%, and 100% of animals inoculated with 10(5), 10(6), or 10(7) cfu, respectively. The magnitude of bacteremia in surviving, bacteremic animals increased for 96 hours after inoculation and then decreased after a plateau phase. Osteomyelitis and septic arthritis occurred only in chicks that were continuously bacteremic. The occurrence of osteomyelitis was uniform among continuously bacteremic animals and developed 1 to 23 hours after inoculation. Chickens are susceptible to systemic infections with S. aureus. Bacteremia, osteomyelitis, and septic arthritis may be induced in healthy chickens without prior manipulations that depress their resistance.

Animals↗
PubMed1990

MR imaging of pancreas in cystic fibrosis.

The pancreatic regions of 18 patients with cystic fibrosis were analyzed with a 1.5 Tesla MR unit. Signal intensity of the pancreas was correlated with clinical data and ultrasound. A hyperintense pancreas on T1-weighted image was consistent with fatty replacement of pancreatic insufficiency. A pancreas of normal soft tissue intensity was found in two asymptomatic and one symptomatic patient. A very hypointense pancreas on any pulse sequence was considered to be an intermediate stage of pancreatic degeneration.

Adolescent↗
PubMed1989

Beckwith-Wiedemann syndrome and its association with type III polycystic kidney disease.

Two cases from our institution and another from the literature in which Beckwith-Wiedemann syndrome (BWS) and type III polycystic kidney disease (PKD) occurring simultaneously are discussed. The importance of recognizing the subtle signs of BWS is stressed, because of the increased risk of malignancies, as well as the need for continued evaluation of patients with BWS for the development and complications of PKD.

Beckwith-Wiedemann Syndrome↗
PubMed1989

Calcification of the ductus venosus: a cause of right upper quadrant calcification in the newborn.

The authors report three cases of ductus venosus calcification as an additional cause of vascular liver calcification in the newborn. All three infants had umbilical venous catheters. The calcification may be caused by extravasated fluids given through the catheter or by local trauma due to catheter insertion. An obliquely oriented, paravertebral "tram-track" calcification in the right upper quadrant, particularly in a premature infant with a history of umbilical venous catheterization, should suggest the diagnosis of calcified ductus venosus.

Calcinosis↗
PubMed1980

Antifreeze glycoproteins from Polar fish. Effects of freezing conditions on cooperative function.

Antifreeze glycoproteins and glycopeptides that function noncolligatively contribute one-third of the freezing temperature depression in the blood serum of some polar fishes and enable them to survive at low temperature (-1.9 degree C). There are at least eight closely related glycoproteins and glycopeptides ranging in molecular weight from 32,000 to 2,600 and numbered 1 to 8 in order of decreasing size. Under conditions of negligible supercooling, the glycopeptides have weaker antifreeze activity than the glycoproteins (20% on a weight basis, or 5% on a molar basis); in mixtures of both, their activities are additive. When nucleation is initiated in supercooled solutions (-4 to -5 degrees C), the glycopeptides are inactive, while the glycoproteins still show activity; when mixtures of both are nucleated in supercooled solutions, cooperative potentiation occurs, and the full activities of the glycopeptides are found. On nucleation of supercooled solutions of the glycoprotein alone or of the mixtures, the temperature rises above the freezing temperature ("overshoots") to an extent dependent upon the extent of supercooling; the temperature of the sample then decreases to form a plateau at the true freezing temperature.

Animals↗
PubMed1979

Isolation and characterization of porcine beta-casein.

Porcine beta-casein was isolated by chromatography on DEAE-cellulose. The protein had a molecular weight of 24 900 as determined by gel filtration on Sephadex G-100 in guanidine-HCl. Its amino acid composition differed from bovine beta-casein especia-ly in respect to serine, alanine and leucine. In common with bovine beta-casein the N-terminal amino acid was arginine; the C-terminal was either alanine or valine, while the C-terminal of bovine beta-casein is valine. At any temperature porcine beta-casein was more sensitive to Ca2+ than bovine beta-casein, while at a fixed Ca2+ concentration porcine beta-casein aggregated at a lower temperature than bovine beta-casein. Porcine beta-casein was susceptible to hydrolysis by calf chymosin but the proteolytic specificity differed from that of calf chymosin on bovine beta-casein.

Amino Acids↗
PubMedDate not supplied

Lymphoproliferative disorder involving the liver following transplantation: CT appearance.

OBJECTIVE: Our goal is to report the CT findings of liver involvement in lymphoproliferative disease in immunosuppressed patients. MATERIALS AND METHODS: We report CT findings in two cases of lymphoproliferative disease involving the liver. RESULTS: The findings of this disorder are nonspecific both clinically and radiographically. CONCLUSION: Nonspecific nodular pattern in the liver on CT may represent unrestricted lymphocytic infiltration in the immunosuppressed patient.

Bone Marrow Transplantation↗