Biomedical subjects

H Goos

Publications and source records attributed to H Goos.

At least 19 recordsLinked to original sources

PubMed2001

Testosterone inhibits 11-ketotestosterone-induced spermatogenesis in African catfish (Clarias gariepinus).

Male fish produce 11-ketotestosterone as a potent androgen in addition to testosterone. Previous experiments with juvenile African catfish (Clarias gariepinus) showed that 11-ketotestosterone, but not testosterone, stimulated spermatogenesis, whereas testosterone, but not 11-ketotestosterone, accelerated pituitary gonadotroph development. Here, we investigated the effects of combined treatment with these two types of androgens on pituitary gonadotroph and testis development. Immature fish were implanted for 2 wk with silastic pellets containing 11-ketotestosterone, testosterone, 5alpha-dihydrotestosterone, or estradiol-17beta; cotreatment groups received 11-ketotestosterone in combination with one of the other steroids. Testicular weight and pituitary LH content were higher (two- and fivefold, respectively) in the end control than in the start control group, reflecting the beginning of normal pubertal development. Treatment with testosterone or estradiol-17beta further increased the pituitary LH content four- to sixfold above the end control levels. This stimulatory effect on the pituitary LH content was not modulated by cotreatment with 11-ketotestosterone. However, the stimulatory effect of 11-ketotestosterone on testis growth and spermatogenesis was abolished by cotreatment with testosterone, but not by cotreatment with estradiol-17beta or 5alpha-dihydrotestosterone. Also, normal pubertal testis development was inhibited by prolonged (4 wk) treatment with testosterone. The inhibitory effect of testosterone may involve feedback effects on pituitary FSH and/or on FSH receptors in the testis. It appears that the balanced production of two types of androgens, and the control of their biological activities, are critical to the regulation of pubertal development in male African catfish.

Animals↗

PubMed2000

Vasa protein expression and localization in the zebrafish.

Primordial germ cell (PGC) development in the zebrafish is poorly understood. The expression of vasa RNA, the only molecular marker so far found to be expressed in fish PGCs, suggests its function in the establishment of the germline. The protein product of vasa is present throughout the life cycle in the germline of Drosophila, Caenorhabditis and Xenopus. The expression pattern of the Vasa protein in zebrafish, is still unresolved. We generated an anti-Vasa polyclonal antibody and show that it is maternally expressed initially throughout the embryo. Interestingly, from the two-cell- to the 1000-cell stage the protein is highly concentrated in two 'dots' near the center of the blastomeres and as such remains longest detectable in the animal pole blastomeres. The first distinct cell-specific expression occurs at 60% epiboly on one side of the blastoderm margin. The Vasa protein in the PGCs is organized in a subcellular granular-like conformation which is dynamic throughout development.

Animals↗

PubMed1997

Distinct efficacies for two endogenous ligands on a single cognate gonadoliberin receptor.

A cDNA encoding a putative gonadoliberin receptor was cloned from the pituitary of the African catfish. Conceptual translation predicts a protein of 379 amino acids which shows typical characteristics of GTP-binding-protein-coupled receptors. The isolated cDNA was stable expressed in human embryonic kidney (HEK) 293 cells which were used for studies on gonadoliberin-activated second messenger systems (inositol phosphate production; increase in cAMP and/or intracellular Ca2+). The isolated cDNA encoded a functional receptor, designated catfish gonadoliberin receptor (cfGnRH-R), which had an amino acid sequence similarity of 38% with mammalian gonadoliberin receptors. In contrast to its mammalian counterparts which lack an intracellular carboxy-terminal domain, the cfGnRH-R contains an additional 49 amino acid residues. From the two endogenous gonadoliberins in African catfish, chicken gonadoliberin-II had a several hundredfold higher potency than catfish gonadoliberin to activate cfGnRH-R-associated second messenger systems in transfected HEK 293 cells. This is in line with the previously determined higher gonadotropin-release capacity of chicken gonadoliberin-II in catfish. Stimulation of second messenger systems with chicken gonadoliberin-II, but not with catfish gonadoliberin, resulted in a biphasic effect and chicken gonadoliberin-II led to a higher maximum stimulation than catfish gonadoliberin. Challenging cfGnRH-R simultaneously with chicken gonadoliberin-II and catfish gonadoliberin did not lead to additive effects. In contrast, two types of mutual inhibitory effects were recorded. These data indicate that a single cognate cfGnRH-R couples with distinct efficacies to signal transduction systems upon stimulation by the two endogenous gonadoliberins which, in addition, may interact negatively.

Amino Acid Sequence↗

PubMed1994

Isolation, characterization and expression of cDNAs encoding the catfish-type and chicken-II-type gonadotropin-releasing-hormone precursors in the African catfish.

The cDNAs encoding the catfish prepro-gonadotropin-releasing hormone and the chicken prepro-gonadotropin-releasing hormone II of the African catfish (Clarias gariepinus) have been isolated and sequenced. The catfish gonadotropin-releasing-hormone precursor and the chicken gonadotropin-releasing-hormone-II precursor have the same overall architecture as other gonadotropin-releasing-hormone precursors identified so far; each is composed of a signal peptide, gonadotropin-releasing hormone and a gonadotropin-releasing-hormone-associated peptide which is connected to gonadotropin-releasing hormone and chicken gonadotropin-releasing hormone II, in combination with the Gly-Lys-Arg sequence, are highly conserved during evolution when compared with the corresponding regions of mammalian, avian (chicken gonadotropin-releasing hormone I) and other fish gonadotropin-releasing-hormone precursors. However, the gonadotropin-releasing-hormone-associated peptide regions are markedly divergent. Northern-blot analysis revealed the presence of a single catfish gonadotropin-releasing-hormone mRNA species of about 470 bases, and the presence of a single chicken gonadotropin-releasing-hormone-II mRNA species of about 650 bases in the African catfish brain. In situ hybridization revealed catfish gonadotropin-releasing-hormone cell bodies rostro-caudally scattered in the olfactory nerve, along both sides of the midline of the telencephalon, in the preoptic area of the ventral hypothalamus, and in the infundibular stalk close to the pituitary. Chicken gonadotropin-releasing-hormone-II cell bodies, however, were exclusively found in the midbrain tegmentum.

Amino Acid Sequence↗

PubMed1993

[The effect of timing of surgical intervention on fatality of acute endocarditis].

Between 1/1986 and 5/1992 a total of 5283 surgical procedures involving extracorporal circulation were performed at our clinic, including 44 patients who underwent a total of 54 operations for acute endocarditis. On the basis of a retrospective study, this paper presents the pre-operative findings and the results of surgery in relation to the duration of the case history. Pathogenic microorganisms were successfully grown from the blood cultures of 63.6% (n = 31) of the patients. Among these microorganisms were viridans streptococci (n = 12), coagulase-negative staphylococci (n = 5), staph. aureus (n = 5), beta-haemolytic streptococci (n = 2) as well as combined infections (n = 2) and miscellanea. Preoperatively, 38 patients were in NYHA stage III or IV. Surgery resulted in an average improvement of 1.6 NYHA classes from NYHA 3.3 to NYHA 1.7. The total-mortality rate was n = 13; early mortality was n = 3. The mean follow-up period was 3.9 years (minimum 5 weeks, maximum 6.4 years). The time elapsed between initial clinical manifestation of the disease and operation had a significant influence on mortality and on the prevalence of complications. Patients who died of endocarditis had a significantly longer case history (p < 0.05). The prognosis was poorer, according to our data, if the case history extended over more than 80 days. Our results demonstrate clearly the necessity for such patients to be referred to a heart surgeon without delay.

Adolescent↗

PubMed1993

[Isolated florid pulmonary valve endocarditis].

We report on a case of isolated pulmonary valve endocarditis caused by coagulase-negative staphylococci 22 years after total correction of a pentalogy of Fallot. The M-mode and two-dimensional echocardiographic findings are presented, and the patient's clinical progress is described. An overview of the literature shows isolated endocarditis of the pulmonary valve to be an exceptionally rare occurrence. 6 months postoperatively, the patient has not been experiencing a relapse and is now in NYHA stage I.

Adult↗

PubMed1992

Two gonadotropin-releasing hormones from African catfish (Clarias gariepinus).

Two forms of gonadotropin-releasing hormone (GnRH) have been purified from brain extracts of the African catfish, Clarias gariepinus, using reverse-phase high performance liquid chromatography (HPLC) and radioimmunoassay (RIA). The amino acid sequences of both forms of African catfish GnRH were determined using Edman degradation after digestion with pyroglutamyl aminopeptidase. In addition, both GnRHs were studied by mass spectrometry. The primary structure of African catfish GnRH I is identical to Thai catfish GnRH I, pGlu-His-Trp-Ser-His-Gly-Leu-Asn-Pro-Gly-NH2, and the primary structure of African catfish GnRH II is identical to the widely distributed and highly conserved chicken GnRH II, pGlu-His-Trp-Ser-His-Gly-Trp-Tyr-Pro-Gly-NH2.

Amino Acid Sequence↗

PubMed1992

Comparison of myectomy alone or in combination with mitral valve repair for hypertrophic obstructive cardiomyopathy.

UNLABELLED: Between 1/84 and 6/91 56 patients were treated for hypertrophic obstructive cardiomyopathy (HOCM): the Morrow technique alone was performed on 40 patients (group 1), in 16 patients (group 2) an additional replacement (n = 13) or reconstruction (n = 3) of the mitral valve was indicated. In a total of 14 cases coronary artery bypass grafting and aortic valve replacement was performed in addition. Postoperatively (mean follow-up 4.2 yrs, 141 patient-years) left-ventricular diastolic and systolic function parameters, heart muscle mass, ECG findings, and symptomatology were recorded and the ratios of beta-adrenoreceptor density to density of the calcium channel were measured. RESULTS: Pressure gradient decreased from 69.2 +/- 5.2 (group 1) and 75.1 +/- 4.8 (group 2) to 23.3 +/- 2.7 and 11.7 +/- 2.2 mmHg postoperatively. Likewise Sokolow-Lyon index decreased from 3.5 +/- 0.2/3.7 +/- 0.2 to 2.9 +/- 0.2/2.8 +/- 0.3. The quotient time-to-peak-velocity/left-ventricular-ejection-time decreased significantly in group 2 from 58.6 +/- 6.3 to 41.9 +/- 5.8 (p less than 0.05). The heart muscle mass, determined echocardiographically, decreased from 680g to 430g (p less than 0.05). Isovolumetric tension time, isovolumetric relaxation time, and E/A ratio at rest and after stress showed typical characteristics. Ca(++)-channel density was clearly raised in all patients, with no differences between the two groups being observable. We conclude from our results: The most marked improvements in clinical and left-ventricular functional parameters were experienced by patients in group 2 (myectomy+MVR).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

[Clinical and hemodynamic results of surgical correction of hypertrophic obstructive cardiomyopathy].

The value of transaortal subvalvular myectomy after Morrow remains unclarified. We therefore analysed our results with HOCM with particular attention to the operation risk and the longterm results. 56 patients were treated at the Leipzig Heart Centre between January 1984 and August 1990 using the transaortic myectomy. In 16 patients an additional mitral valve replacement or -reconstruction was required. In 14 patients, other combined operations (aortic valve replacement, aortocoronary bypass) were indicated. In the postoperative observation period (up to 7 years; 141 patient-years; mean follow-up 4.2 yrs) detailed information was obtained at regular intervals about subjective complaints, ECG changes, left ventricular functional parameters and the weight of the heart muscle mass were recorded. The myectomy resulted in an alteration of the NYHA-class from 3.1 to 1.3 postoperatively (p < 0.05). The ventriculo-aortal pressure gradient reduced in the group myectomy (group I) from 69.2 +/- 5.2 to 23.3 +/- 2.7 mmHg postoperatively. In the myectomy+mitral valve repair group (group II) the intracavitary pressure gradient was even reduced to 11.7 +/- 2.2 Torr (p < 0.05). The Sokolov-Lyon-Index was 3.7 +/- 0.19 mV preoperatively and went down to 2.9 +/- 0.16 mV. The heart muscle mass decreased from 680 g to a postoperative value of 430 g (p < 0.05). The relation of BAR and calcium channel density of 0.5 +/- 0.1 in HOCM versus 0.9 +/- 0.08 in a control group (n = 6) proves the increased number of calcium channels in HOCM.

Adolescent↗

PubMed1992

[Immunologic studies in patients with dilated cardiomyopathy].

In 10 cases of dilated cardiomyopathy the HLA-loci (A, B, C, DR) and marker expression on lymphocytes were studied. In this group the T4/T8-ratio was decreased and interleukin-2-expression was increased in relation to normals or patients with chronic coronary heart disease, respectively. 9 patients had the HLA-A1 or HLA-A2-locus in their siblings. In correlation analysis between immunological and hemodynamic parameters a good correlation of the number of NK-cells to the ejection fraction (r = 0.79) and negative correlation of helpercells (CD4) to the cardiac output were found (r = -0.80). The results of this attempt suggest an immunological pathogenesis of the dilated cardiomyopathy.

Adult↗

PubMed1990

[Hypertrophic obstructive cardiomyopathy].

Today, with the help of modern echocardiographic techniques we are able not only to describe the characteristic changes when a HOCM is present and to determine the intracavitary pressure gradient, but also recognize the functional irregularities typical for the HOCM. Thus, the methodical progress of the echocardiography has essentially enlarged our knowledge about the pathophysiology of this clinical picture. Today, the echocardiography is the method of choice for the diagnostics of the HOCM and for the judgment of the functional consequences of therapeutic interventions.

Cardiomyopathy, Hypertrophic↗

PubMed1990

[Echocardiography evaluation of the surgical result in hypertrophic obstructive cardiomyopathy].

Despite the small cohort of patients with HOCM could be shown that the routine application of the conventional and colour Doppler echocardiography after myectomy is indicated and reasonable. The modern echocardiography is able to assess with high individual reliability the therapeutic aim of myectomy--drastic reduction of the intracavitary pressure gradient. Significant changes were also the results in the systolic acceleration time (TPVS/LVET standardized on the LVET and the diastolic measuring parameters VmaxE, ATE and TVIE/TVIA), the importance of which is partly still fully open.

Adult↗

PubMed1990

[Emergency coronary surgery in patients with unstable angina pectoris. Results and place in the total concept of the treatment of this group of patients].

The urgent coronary surgery performed in patients with high risk unstable angina (rest pain greater than 48 h) shows still different results. We found in 57 urgent operated patients the same functional and clinical results as after elective bypass grafting. A higher in hospital mortality after urgent coronary surgery based on a higher number of grafts are occluded in the early postoperative period. The better prognosis concluded that the use of urgent coronary surgery is the therapy of choice in patients with refractory unstable angina pectoris.

Adult↗

PubMed1989

[The relation of anthropometric parameters and echocardiography findings in the evaluation of left ventricular form and function in extreme obesity].

For the characterization of the left-ventricular thickness of the wall, of the diameter and of the functional parameters in obesity in a short-term investigation on 18 extremely adipose female normotonics and 17 normotonics with normal weight the echocardiographic investigation in the M-mode in the short parasternal axis was performed. The women with overweight had a by 28% (p less than 0.001) greater fractional shortening, a by 8% (p less than 0.01) greater ejection fraction, a by 23% (p less than 0.05) greater stroke volume and a by 34% (p less than 0.001) greater cardiac output as well as a by 13% smaller left-ventricular end-systolic volume than normotonic women with normal weight. Index of stroke volume and cardiac output did not differ. The women with overweight had a significantly larger left-ventricular end-diastolic diameter and a thicker interventricular septum as well as a larger thickness of the left-ventricular posterior wall in the systole. The results allowed the conclusion that changed left-ventricular parameters both with regard to the form and to the function in obesity per se might be the expression of the physiological adaptation to an increased requirement and the borderlines to the transition into a disturbed left-ventricular function and development of a left-ventricular hypertrophy were not fixed. Long-term studies should bring further explanation concerning these problems.

Adult↗

PubMed1989

A new member of the gonadotropin-releasing hormone family in teleosts: catfish gonadotropin-releasing hormone.

Two forms of immunoreactive gonadotropin-releasing hormone (GnRH) were detected in extracts of brain-pituitary tissue from the African catfish, Clarias gariepinus. Catfish I GnRH eluted first from reverse-phase HPLC and was present in larger amounts compared with catfish II GnRH. Chromatographic and immunological studies with four antisera provide evidence that catfish I GnRH is unique compared with identified GnRHs from mammal, chicken, salmon, and lamprey. Catfish II GnRH elutes in the same position as chicken II GnRH and the forms cannot yet be distinguished. GnRHs extracted from female and male catfish tissue appear to be similar in terms of the number of peaks eluted, elution position, quantity, and cross-reactivity with the antisera. The results of the HPLC and radioimmunoassay studies suggest that catfish I GnRH is likely to be 10 amino acids in length, and have an amide at the C terminus similar to the other family members. In addition, catfish I GnRH is probably different in the 5 to 10 amino acid region compared with mammalian GnRH. Finally, catfish I GnRH is likely to have a lysine or arginine residue as it is the most hydrophilic family member. The lack of the salmon form of GnRH and the presence of a unique GnRH form constitute another example of the considerable evolutionary variation that has occurred in the catfish family compared with other teleosts.

Animals↗

PubMed1989

Influence of iloprost on eicosanoid generation and lipid levels in experimental myocardial ischemia in dogs.

Anaesthetized mongrel dogs were subjected to occlusion of a coronary artery. The resulting myocardial infarction was observed for three hours. One hour after occlusion, infusion of the stable prostacyclin analogue iloprost or saline was started. In the control group myocardial infarction was associated with an increase of the ratio TXB2/6-keto-PGF1a which was abolished by iloprost treatment. After occlusion in the control group, the atherosclerosis index (TC-HDLC): HDLC was increased, but in the iloprost-treated group it was significantly decreased. The results of this study suggest that the administration of iloprost is able to prevent changes in eicosanoid metabolism and lipoprotein pattern after coronary artery occlusion in dogs.

6-Ketoprostaglandin F1 alpha↗

PubMed1988

Action of iloprost and PGE1 on global ischemic and reperfused myocardium: a 31P-NMR-study.

The influence of iloprost, PGE1 and of the combined application of iloprost and PGE1 on high energy phosphate contents was investigated in isolated rat hearts perfused aerob at 37 degrees C in Langendorff mode. Changes in creatine phosphate, ATP and inorganic phosphate were registered during 20 minutes of global ischemia and 56 minutes of reperfusion with 31P-NMR-spectroscopic methods starting drug application prior to ischemia simultaneously with onset of heart perfusion. Most effective in preservation of high energy phosphates was the combined application of PGE1 and iloprost resulting in a creatine phosphate/inorganic phosphate ratio of 103.2 +/- 30.9% of pre-ischemia values compared to 52.5 +/- 6.1% in control group without drug application 0-5 minutes after onset of reperfusion, 148.8 +/- 24.8% vs 78.8 +/- 15.2% at 6-11 minutes of reperfusion and 116.6 +/- 16% vs 68.9 +/- 12.7% at 12-17 minutes of reperfusion. The same trend was observed employing ATP/inorganic phosphate ratio. The improved energy state in reperfused hearts following application of PGE1 and iloprost in combination is presumed to be supported by a reduction of the loss of high energy phosphates (HEP) during global ischemia and by a cytoprotective effect of iloprost immediately after starting reperfusion.

Alprostadil↗

PubMed1988

Influence of drugs on the TXA2/PGI2 balance and on the atherogenic index in myocardial ischemia in dogs.

The effect of drugs on eicosanoid production and on the development of atherogenic index was investigated in canine myocardial ischemia. Iloprost, verapamil, the trapidil derivative AR 12463 or 0.9% NaCl solution were administered 60 min after coronary artery ligation in anaesthetized dogs. Both iloprost and AR 12463 reduced the thromboxane A2/prostacyclin (TXA2/PGI2) ratio in coronary sinus plasma in comparison to controls. The atherogenic index was significantly decreased in the iloprost as well as in the AR 12463-treated group in comparison to the control group. Verapamil had no influence on the investigated parameters.

Animals↗