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Biomedical subjects

M Hallberg

Publications and source records attributed to M Hallberg.

At least 19 recordsLinked to original sources
PubMed1998

Molecular characterization of the human carbonic anhydrase-related protein (HCA-RP VIII).

The very evolutionarily conserved human carbonic anhydrase-related polypeptide (CA-RP VIII) lacks the carbon-dioxide hydration-activity, characteristic of the enzymatically active carbonic anhydrases. We have expressed HCA-RP VIII as a glutathione-S-transferase fusion protein (GST-HCA-RP VIII). The purified HCA-RP VIII showed a substantially higher apparent molecular weight by gel-filtration compared to the molecular weight calculated from the amino acid sequence, indicating a larger than expected Stoke's radius. Like other studied CA's, the protein unfolds through two transitions at increasing concentrations of guanidine hydrochloride. The far-UV CD spectra of HCA-RP VIII indicates a secondary structure similar to that of the catalytically active HCA II. The very high sequence identity between human and mouse CA-RP VIII (98%), might indicate that the function of the protein involves binding of another protein. However, an attempt to use the GST-HCA-RP VIII fusion protein to affinity purify a ligand was unsuccessful.

Biomarkers, Tumor↗
PubMed1994

Catalytic effects of glutathione peroxidase mimetics on the thiol reduction of cytochrome c.

The reduction of ferric cytochrome c by various thiols was studied. It was found that L-cysteine, L-cysteine methyl ester and D-penicillamine were very efficient reductants for cytochrome c, whereas N-acetylated amino acids (N-acetyl-L-cysteine and N-acetyl-D-cysteine) reacted considerably slower. A series of glutathione peroxidase mimetics and related compounds were studied as catalysts for the N-acetyl-L-cysteine reduction of ferric cytochrome c. Diphenyl diselenide, t-butylthio phenyl selenide, S-(phenylseleno)-glutathione, N-(phenylseleno)-phthalimide and alpha-(phenylselenenyl)-acetophenone were all efficient reduction catalysts. Diphenyl disulfide, Ebselen and several derivatives thereof were less potent catalysts whereas diaryl selenides and diphenyltelluride did not affect the rate of reduction when present in catalytic amounts. The catalysis of diphenyl diselenide, selenosulfides, alpha-(phenylselenenyl)acetophenone, N-(phenylseleno)-phthalimide and Ebselen and derived compounds was suggested to involve the formation of areneselenolate ions as redox-active species capable of transferring one electron to the ferric cytochrome c. The resulting selenium centered arylseleno radicals would then dimerize to regenerate the catalyst in the diselenide form. In the presence of diaryl ditellurides and N-acetyl-L-cysteine, ferric cytochrome c was also rapidly reduced. This reaction was stoichiometric with respect to the ditelluride reagent.

Cytochrome c Group↗
PubMed1992

Flowmetric evaluation of internal mammary artery flap during repair of aortic coarctation.

Resection of the internal shelf through a longitudinal aortotomy and widening with the free end of the left in situ internal mammary artery (IMA) were steps in correction of aortic coarctation with isthmus hypoplasia in nine patients aged 9-14 (mean 10.5) years. Electromagnetic flowmetry was performed on the left IMA before and after the repair. The essential finding was considerably increased mean blood flow in the IMA flap during cross-clamping proximal to the completed repair, from 53 +/- 48 to 430 +/- 74 ml/min (378 +/- 78%). The IMA thus is a powerful conduit with extraordinary flow capacity when runoff is appropriate. Integration of IMA as a viable flap in the repair of aortic coarctation implies that this artery increases its collateral flow contribution to the distal aorta.

Adolescent↗
PubMed1991

Estimation of Doppler gradients at rest and during exercise in patients with recoarctation of the aorta.

In patients with suspected recoarctation of the aorta the estimation of the pressure difference between the arms and legs is an important part of the examination. Because this difference is often augmented when the circulation is stressed by exercise, exercise tests are a useful part of the evaluation. Doppler echocardiography was used to estimate this pressure difference in 16 adult patients in whom simultaneous pressure and Doppler recordings were made both at rest and during exercise. There was a close correlation between the invasive peak instantaneous gradient and the Doppler gradient both at rest and during exercise. There was only a moderate correlation between the invasive peak to peak gradient and the Doppler gradient at rest and during exercise. Doppler echocardiography is recommended as an easy and accurate method of estimating the peak instantaneous gradient both at rest and during exercise in patients with suspected recoarctation.

Adult↗
PubMed1989

The internal mammary artery free and flap aortoplasty in coarctation of the aorta.

A technique for correction of aortic coarctation is described in which the left internal mammary artery (IMA) is distally divided for integration in the repair. After resection of the internal coarctation ridge, the distal end of the freed IMA is obliquely severed, opened to required length and thus fashioned as a widening flap suitable fro aortoplasty. IMA free end flap aortoplasty gave promising early results in seven patients aged 10-15 years with aortic coarctation and IMA of good quality and calibre.

Adolescent↗
PubMed1989

The internal mammary artery origin flap aortoplasty in coarctation of the aorta.

The left internal mammary artery (IMA) was divided proximally to form an integral part of the repair in coarctation. After resection of the internal coarctation ridge, the origin of the IMA was obliquely divided, opened to required length and thus fashioned as a widening flap for aortoplasty. This procedure preserves distal continuity of the IMA with direct blood supply to the breast. The 'origin flap' aortoplasty gave promising early results in six patients and 10-17 years with aortic coarctation and IMA of suitable calibre and good quality.

Adolescent↗
PubMed1989

Neonatal endocarditis requiring surgery.

A case of infective endocarditis in a neonate is reported. Echocardiography demonstrated a large (1 X 1.5 cm) vegetation on the anterior mitral leaflet protruding into the ventricle during diastole. The left atrium was enlarged and Doppler showed mitral regurgitation. Excision of the vegetation during effective antibiotic treatment involved no complications. Although histologically the endocarditis was in the early stage of healing, surgical removal of large, floppy vegetations is advocated because of the unpredictable risk of catastrophic embolization.

Anti-Bacterial Agents↗
PubMed1987

The internal mammary artery as subclavian artery substitute in repair of coarctation of the aorta with subclavian flap technique.

In three children, aged 11, 11 and 13 years, long isthmic tubular hypoplasia of the aorta technically precluded resection and end-to-end anastomosis. The coarctation was instead corrected by means of a subclavian flap. Anastomosis between the distal end of the left internal mammary artery and the descending aorta permitted perfusion of the remaining portion of the subclavian artery. At invasive reexamination 6 months after surgery, there was adequate functional and anatomic relief of coarctation in all three children. The three mammary artery-aorta anastomoses were patent, which probably prevented the potential ischemia of the left arm after ligation of the subclavian artery.

Adolescent↗
PubMed1986

Cuff pressures and Doppler gradients after coarctectomy. A long-term follow-up.

Fourty-six adult patients operated on as children with resection and end to end anastomosis because of coarctation of the aorta were studied. The age at operation was 7 to 13 years (mean age 10 years) and at follow-up 18 to 28 years (mean age 21 years). Arm and thigh cuff pressure was measured at rest, during and immediately after submaximal exercise. The systolic gradients were also estimated using continuous wave Doppler. Systolic blood pressure at rest was 150 mmHg or more in 12 patients (26%). The cuff pressure at rest correlated well with arm-leg gradients at rest and at work, and also with the Doppler gradients at rest. Doppler gradients slightly underestimated invasively measured gradients. The results imply that postoperative hypertension was explained by residual mechanical obstruction.

Adolescent↗
PubMed1984

Amphetamine secretion in breast milk.

The excretion of amphetamine in human breast milk was studied in a nursing mother with narcolepsy, who was treated with 20 mg daily of a racemic preparation of amphetamine. The concentration of amphetamine was 3 and 7 times higher in breast milk than in maternal plasma on the 10th and 42nd days after delivery. Small amounts of amphetamine were found in urine samples from the infant.

Adult↗