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Biomedical subjects

G Frank

Publications and source records attributed to G Frank.

At least 181 records · Page 10Linked to original sources
PubMed1987

Late increase in luminal diameter of aortocoronary venous bypass grafts associated with an increase in the vascular region under supply.

In a previous study, a significant inverse relation was found between the luminal size of aortocoronary venous bypass grafts and the vascular resistance of the coronary region that was perfused by the bypass graft in late stages after bypass surgery. This observation suggested that changes in the graft-dependent vascular area could influence the luminal size of the vein graft, even when they occurred several years after operation. Whereas it is well established today that aortocoronary vein grafts often decrease in luminal diameter after implantation, an increase in the bypass lumen has so far not been reported. Therefore, changes in luminal diameter of 27 vein grafts in 21 patients who underwent at least two postoperative angiographic studies (first study 8 +/- 5 months after surgery, second study 58 +/- 32 months after surgery) were compared with the size of the vascular region supplied by the bypass. The graft diameter was found to be unchanged between the two studies (3.3 +/- 0.6 versus 3.4 +/- 0.7 mm, p = NS) when the dependent vascular area was unchanged. A significant increase in graft diameter from 2.8 +/- 0.8 to 3.9 +/- 0.9 mm (p less than 0.001) was observed in nine patients in whom the area of perfusion had increased between the two studies because of the development of occlusion or obstruction of major coronary branches that were now perfused from the grafted vessel by way of collateral vessels. These data support the contention that the luminal size of aortocoronary vein grafts can adapt to the needs of the dependent myocardial vascular region even late after operation rather than being the result of a nonreversible degenerative process as commonly assumed.

Adult↗
PubMed1987

Surgical decision making in acute aortic dissection type A.

In principle there are 3 different approaches to the treatment of acute aortic dissection type A (AADA): replacement of the aortic valve and ascending aorta, reconstruction of these structures, and a combination of both techniques. This study summarizes our experiences with these methods and delineates indication for the different surgical procedures. Since 1979, a total of 51 patients (39 male, 12 female, mean age 45.5 years) underwent surgery for AADA with an overall mortality of 25%. Differences in mortality of the operative variants (reconstruction 12%, composite replacement 18%, combined reconstruction and replacement 47%) predominantly mirror growing experience than applicability of the methods. The follow-up of patients with reconstruction of the aortic valve revealed a reoperation rate of only 9% after 0.3 to 6.3 years. Four patients with constant and minor annuloectasia and/or subclinical aortic insufficiency are observed in short intervals. We conclude, that the operative procedure in AADA must be adapted to the intraoperative pathoanatomical findings. Patients with primary annuloectasia should undergo graft replacement. Reconstruction of the ascending aorta and aortic valve is considered to be the preferable method in patients with primarily normal caliber of the ascending aorta and aortic anulus.

Adult↗
PubMed1987

Hyperthyroidism and high serum levels of TSH associated with pituitary tumour.

We report a 28-year-old male with persistent clinical and laboratory findings of hyperthyroidism associated with marked elevated serum levels of TSH and no response to TRH despite hemithyroidectomy and subsequent antithyroid drug therapy two years previous to admission to our hospital. Subsequent skull X-rays, CT scans and angiographic findings demonstrated the presence of a pituitary tumour. After operation and radiation therapy T3, T4 and TSH levels returned to normal values. Seven years later the patient is still euthyroid. We conclude that hyperthyroidism in our patient was due to excessive secretion of TSH by the pituitary tumour.

Adenoma, Chromophobe↗
PubMed1987

Interleukin 4 is a growth factor for activated thymocytes: possible role in T-cell ontogeny.

We have shown that recombinant or natural interleukin 4 (IL-4) (formerly called B-cell stimulatory factor 1) induces proliferation of activated adult or fetal thymocytes. In the case of adult thymocytes, IL-4 in combination with Con A or phorbol 12-myristate 13-acetate (PMA) stimulated the proliferation of peanut agglutinin (PNA)-negative (-) thymocytes, while PNA-positive (+) thymocytes showed only marginal responses. Further investigation revealed that day 14-17 fetal thymocytes, purified L3T4- LyT2- double-negative adult thymocytes, and single positive L3T4+ LyT2- or L3T4- LyT2+ thymocytes failed to respond to IL-4 or PMA alone but proliferated strongly with both IL-4 and PMA. In contrast, purified double-positive L3T4+ LyT2+ adult thymocytes showed only a marginal proliferative response to these stimuli. Responsiveness of thymic subpopulations to PMA and IL-4 could be inhibited with anti-IL-4 but not with anti-IL-2 monoclonal antibodies, indicating that they were IL-2 independent. Finally, we have observed that supernatants from calcium ionophore and PMA-stimulated adult double-negative L3T4- LyT2- thymocytes induce proliferation of double-negative adult thymocytes. This latter response is inhibited by anti-IL-4 monoclonal antibodies, suggesting that under appropriate stimulation conditions, these immature thymocytes are able to produce IL-4. These observations suggest a role for IL-4 in T-cell ontogeny.

Animals↗
PubMed1987

Expression of the nuclear gene encoding oxygen-evolving enhancer protein 2 is required for high levels of photosynthetic oxygen evolution in Chlamydomonas reinhardtii.

We have cloned a cDNA encoding a 20-kDa polypeptide, oxygen-evolving enhancer protein 2 (OEE2), in Chlamydomonas reinhardtii. This polypeptide has been implicated in photosynthetic oxygen evolution, and it is associated with the photosystem II complex, the site of oxygen evolution in all higher plants and algae. The sequence of OEE2 cDNA, the deduced amino acid sequence of the preprotein, the N-terminal protein sequence of mature OEE2 protein, and the coding regions of the single OEE2 gene are presented. The protein is synthesized with a 57-amino acid N-terminal transit peptide that directs the transport of this polypeptide across three cellular membranes. A nuclear mutant of C. reinhardtii, deficient in oxygen-evolving activity, is shown to be specifically missing OEE2 polypeptides. This mutation, which results in the complete absence of all OEE2 mRNA and protein, does not affect the accumulation of other photosystem II polypeptides or their mRNAs.

Algal Proteins↗
PubMed1987

Pituitary apoplexy, bilateral carotid vasospasm, and cerebral infarction in a 15-year-old boy.

The authors report a case of pituitary apoplexy associated with oculomotor defects and focal cerebral signs; the visual pathways were intact. Computed tomography documented a mass of heterogeneous density within an enlarged sella turcica and a right parietal infarct. Angiograms revealed bilateral carotid spasm and occlusion of the right angular artery. Treatment was conservative. Control angiograms showed spontaneous resolution of the vasospasm and recanalization of the cortical artery. The patient made a complete neurological recovery; he needed only treatment with vasopressin due to transient diabetes insipidus. The risk of vasospasm and brain ischemia should be kept in mind when treating pituitary apoplexy. The early occurrence of vasospasm in our case suggests the participation of powerful vasoactive agents liberated from the tumor.

Adenoma↗
PubMed1987

Interpretation and classification of bone scintigraphic findings in stress fractures.

A new system for classification of stress fractures identified by bone scintigraphy was developed and divided into four grades according to lesion dimension, bone extension, and tracer accumulation. The scintigraphic findings were evaluated for severity of lesions by extent of the visualized bone response, ranging from ill-defined cortical lesions with slightly increased activity (I) to well-defined intramedullary transcortical lesions with intensely increased activity (IV). Bone scintigraphies using [99mTc]MDP were obtained in 310 military recruits suspected of having stress fractures. In 235 patients, 391 stress fractures were diagnosed. Forty percent of the lesions were asymptomatic. Most of the lesions were in the tibiae (72%), and 87% of the patients had one or two lesions, while 13% had three to five lesions. Eighty-five percent of the lesions were classified as mild and showed early and more complete resolution on follow-up studies after treatment as compared to the severe grades. Furthermore, specific scintigraphic patterns have been introduced for distinguishing inflammatory shin-splints from stress fractures, allowing for their appropriate early treatment. Thus, early recognition of mild stress fracture scintigraphic patterns representing the beginning of pathologic bone response to stress enabled a prompt and effective treatment to prevent progression of lesions, protracted disability, and complications.

Adult↗
PubMed1987

[Ectopic atrial tachycardia: surgical therapy (case report and review of the literature)].

Focal atrial tachycardia with frequencies up to 200/min in an 11-year-old girl had been resistant to drugs over a period of 5 years. An electrophysiological study demonstrated a left atrial ectopic tachycardia. Intraoperative epicardial mapping localized the automatic focus at the base of the left atrial appendage. Excision of the appendage and cryoablation of the adjacent area were performed using cardiopulmonary bypass. Histological examination of the excised tissue showed no specific alterations aside from islets of fatty tissue. The girl has been in sinus rhythm and has shown no tachycardias during the 6 months following the operation. Review of the literature covering 17 cases of right and 12 cases of left atrial focal tachycardia indicates excision of the atrial tissue in combination with cryoablation to be the treatment of choice to ensure success.

Child↗
PubMed1986

On embodiment: a case study of congenital limb deficiency in American culture.

The relationship of mind and body is an issue of importance for Western medicine and psychiatry. An area to which this problem particularly applies is that of physical disability. In evaluating treatment of persons with physical disabilities, the concept of "adjustment" in social psychology may not deal sufficiently with ambiguities arising in varied cultural settings. The related concept of "stigma" in sociology is also limited, covering the cosmetic aspect of the mind-body relationship only. This paper applies the more abstract and inclusive concept of "embodiment" from the phenomenological movement in philosophy to the life history of a 35-year-old American woman born with quadrilateral limb deficiencies. The resulting description of her functioning and self-image over time calls into question the cultural assumptions of rehabilitation medicine and highlights the more general cultural demands upon persons with severe physical disabilities in the United States since the 1950s.

Adult↗
PubMed1986

Successful surgical treatment of focal atrial tachycardia--a case report and review of the literature.

Focal atrial tachycardia with frequencies up to 200/min in an 11-year-old girl had been resistant to drugs over a period of 5 years. An electrophysiological study demonstrated a left atrial ectopic tachycardia. Intraoperative epicardial mapping localized the automatic focus at the base of the left atrial appendage. Excision of the appendage and cryoablation of the adjacent area were performed using cardiopulmonary bypass. Histologic examination of the excised tissue showed no specific alterations aside from islets of fatty tissue. The girl has been in sinus rhythm and has shown no tachycardias during the 6 months following the operation. A review of the literature, covering 17 cases of right and 12 cases of left atrial focal tachycardia, indicates excision of the atrial tissue in combination with cryoablation to be the treatment of choice to ensure success.

Child, Preschool↗
PubMed1986

Structure and function of L-lactate dehydrogenases from thermophilic and mesophilic bacteria, IV. The primary structure of the mesophilic lactate dehydrogenase from Bacillus subtilis.

The complete amino-acid sequence of lactate dehydrogenase from the mesophilic Bacillus subtilis (B. X1) was determined. Approximately 70% of the sequence was obtained by sequence analysis of intact protein (N-terminal sequence) and of four CNBr fragments (CNBr3, CNBr4, CNBr5 and CNBr6). Sequences overlapping the CNBr fragments were determined from polypeptide fragments obtained by cleavage using o-iodosobenzoic acid (cleavage at Trp) or clostripain (cleavage at Arg). The C-terminal amino-acid residue (Asn) was detected by carboxypeptidase Y-degradation. Lactate dehydrogenase from B. subtilis shows a 69% sequence homology to that from the thermophilic strain B. stearothermophilus, and a 34% sequence homology to those from higher organism. The homology of these enzymes is particularly high at the active site regions (the coenzyme and substrate binding sites). The relatively high sequence conservation of the lactate dehydrogenases from B. subtilis and B. stearothermophilus (and from other bacilli) allows a structural comparison of this temperature variants.

Amino Acid Sequence↗
PubMed1986

Metabolism of 3-nitrophenol by the frog Rana temporaria.

Frogs injected with 3-nitrophenol excreted 85-93% of the administered dose within 17 h; 70-90% dose was metabolized. Metabolites identified comprise 3-nitrophenyl glucuronide (57% dose), 3-nitrophenyl sulphate (24% dose), and 3-acetamidophenyl sulphate (2% dose). Traces of the following metabolites were found: 3-acetamidophenyl glucuronide, 3-acetamidophenol, 4-nitrocatechol, nitroquinol, 4-nitrocatechol sulphate and nitroquinol sulphate.

Animals↗
PubMed1986

[Mycotic intracranial aneurysm in infective endocarditis of the mitral valve].

A 20-year-old woman suffering from mitral valve endocarditis due to streptococcus faecalis infection after blunt trauma and splenectomy complained of severe headache 18 days later. Cerebral angiography showed a left posterior artery aneurysm. A craniotomy was performed and the aneurysm could be successfully removed. The postoperative neurological status showed a mild transient right hemiparesis. The patient underwent mitral valve replacement with a St. Jude-Medical prosthesis 14 days after brain surgery. The patient was in stable neurologic and hemodynamic conditions at the time of discharge 3 weeks after valve replacement.

Adult↗