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Biomedical subjects

M Zeman

Publications and source records attributed to M Zeman.

At least 19 recordsLinked to original sources
PubMed1992

Development of melatonin rhythm in the pineal gland and eyes of chick embryo.

A melatonin rhythm was observed in the pineals of 18-day-old chick embryos incubated under a light-dark regime of 18: 6 h. A low pineal melatonin content was found during the light phase of the day. Concentrations started to increase 2 h after dark onset and reached maximum levels after 4 h of darkness. The amplitude of the pineal melatonin rhythm increased considerably after 2 days and night-time concentrations in 20-day-old embryos were more than 5 times higher than in 18-day-old ones. Significant day/night differences in melatonin production were found both in pineals and eyes. Exposure of eggs to 1 h of light during the dark period decreased the high melatonin concentrations in the eyes but not in the pineals of the 20-day-old chick embryo. The results suggest that in this precocial bird at least part of the circadian system may already operate during embryonic life.

Animals↗
PubMed1991

[The importance of plasma lipids and apolipoproteins in the assessment of risk of myocardial infarction in the most common types of primary hyperlipoproteinemias].

In a group of 60 men after myocardial infarction (IM) with primary hyperlipoproteinaemia (HLP), type IIA, IIB and IV the authors revealed on comparison with a control group of 71 men with similar types of HLP where ischaemic heart disease (IHD) was not detected, significantly higher concentrations of total plasma cholesterol (TC), low density lipoproteins (LDL-C), apolipoprotein (apo)B in LDL; in the hyperlipidaemic subjects after IM the concentration of HDL-C was significantly lower as well as the ratio of cholesterol and apo-B in the LDL fraction. In patients with hypercholesterolaemia (HLP IIA and IIB) for estimation of the risk of IHD LDL-C, HDL-C and apo-B in LDL are useful. In patients with hypertriglyceridaemia (HLP IIB and IV) subjects with a history of IM have in addition to a higher concentration of apo-B in LDL a lower ratio of cholesterol to apo-B in LDL and in those with HLP IV also a lower plasma concentration of apo-A-I. By the discriminating function the variable of which is in HLP IIB the apo-B concentration in LDL and in HLP IV apo-B in LDL and apo-A-I in plasma in HLP IIB 77.8% subjects and in HLP IV 82.9% subjects with an increased risk of IHD can be detected.

Apolipoproteins↗
PubMed1990

[Beta-sitosterol in the treatment of hypercholesterolemia].

A group of 28 patients with primary hyperlipoproteinaemia [19X lipoprotein (LP) type IIA, 8X type IIB and 1X a normolipidaemic patient with concurrent hyperapoB lipoproteinaemia] were given for a period of three weeks a dietetic preparation containing phytosterols - 12 g/day. This led to a significant drop of total cholesterol and LDL-cholesterol in plasma. The cholesterol concentration in HDL and both its fractions increased, the differences however were not significant. The triglyceride levels did not change. There was a significant drop of the apolipoprotein B (apo-B) concentration in LDL, the apo-A-I in plasma did not change. There was a significant drop of atherogenic indexes TC/HDL-C, LDL-C/HDL-C and apo-B/-A-I. During investigation of the LCAT activity the authors observed a significant rise of the fractional esterification rate associated with a highly significant drop of the free cholesterol concentration in plasma as a result of treatment. Discrimination analysis of parameters of the lipoprotein metabolism and the patients' body weight before treatment helps to assess a function by means of which it is possible in 92.3% of the subjects to predict the success of treatment before the administration of beta-sitosterol.

Female↗
PubMed1990

Ontogeny of N-acetyltransferase activity rhythm in pineal gland of chick embryo.

1. N-acetyltransferase was present in pineal glands of 14-day-old chick embryos though no rhythm either in LL, DD or LD 12:12 was observed in this age. 2. Daily rhythm in pineal NAT activity was found in 18-day-old embryos incubated under LD 12:12 and LD 16:8 but no NAT rhythm was detected in DD or LL. 3. NAT rhythm persists for 2 days in constant darkness and it may be circadian in nature. 4. Presence of melatonin (85 +/- 8 pg/mg tissue) was detected in pineals of 18-day-old chick embryos.

Animals↗
PubMed1990

Changes in plasma testosterone, thyroxine and triiodothyronine in relation to sperm production and remex moult in domestic ganders.

Changes in plasma testosterone (T), thyroxine (T4), triiodothyronine (T3), semen output and remex moult were studied in domestic ganders. A bimodal pattern in both plasma T and sperm concentration was observed during the annual cycle. Ganders started to produce semen at the end of January; maximum semen volume (0.32 +/- 0.04 ml) and sperm concentration (148 +/- 38 x 10(3)/mm3) were reached in March and a marked decrease was observed after mid-April, when the moult of the remiges began. Plasma T3 levels peaked in February (9.7 +/- 0.6 nmol.l-1) and this peak coincided with maximum T concentrations (9.8-10.4 nmol.l-1). Elevated levels of T4 were found from late February until mid-April (31.0-33.6 nmol.l-1). Plasma T concentration was low at all stages of remex moult and regrowth. Decreased T4 levels were found in ganders during remex regrowth from the "brush" to half of the full primary growth stage. Higher plasma T4 levels were found before and after this stage of the moult. A reverse pattern was observed for T3 concentrations.

Animals↗
PubMed1989

[Cervical vertebrae replacements].

The authors analyze caused and indications for prostheses of bodies of cervical vertebrae. As caused they mention bone tumours, metastases, benign bone tumours and injuries. For operation they indicate patients with neurological symptoms and instability of the spine. For prostheses they use bone grafts from the blade of the ilium. They insert the graft during traction, as described by Crutchfield and do not routine fix it. After operation they immobilize by "Minerva" for three weeks. The method is in case of metastases and bone tumours only palliative, but improves the patients' mobility and prevents the development of early neurological complications.

Bone Transplantation↗
PubMed1989

[Changes in the distal end of the radius from the aspect of the injured person].

Based on an evaluation of a group of patients treated on account of fractures of the wrist. Colles type, we assume that the decisive factor is the type of fracture. We recommend therefore to divide these fractures into two groups. The first one includes all types where the fracture line does not involve the radiocarpal or radioulnar joint. The second one includes all multifragmental intraarticular fractures where an active surgical procedure can improve hitherto achieved therapeutic results.

Female↗
PubMed1989

[The post-traumatic carpal tunnel syndrome].

Chronic carpal canal syndrome (CCC) is a relatively rare post-traumatic complication in the area of the wrist. It develops either as the direct consequence of anatomical narrowing of the osteofibrous canal or hypertrophy of structures inside the canal, most frequently tendon sheaths. As the clinical finding in all our patients improved after release of the compressed median nerve after resection of the ligamentum carpi transversum, we consider this operation absolutely indicated in all posttraumatic carpal canal syndromes.

Adult↗
PubMed1989

[Injuries of the ligaments of the talar joint].

Based on experience with the treatment of 404 patients with injuries of the soft parts of the talus the authors maintain that markedly better results are achieved in patients where sufficiently long immobilization with a plaster bandage was used or where early reconstruction of the injured ligaments was performed. A very important negative factor is treatment of these injuries without immobilization or inadequate immobilization, as a high percentage of the patients develop instability of the talus with all its consequences. The authors consider arthrography the exact diagnostic method, the results of which are decisive for the therapeutic procedure.

Adolescent↗
PubMed1988

Rapid adjustment of the pineal N-acetyltransferase rhythm to change from long to short photoperiod in the Japanese quail (Coturnix coturnix japonica).

The dynamics of adjusting the pineal N-acetyltransferase rhythm from long to short photoperiod was assessed in the Japanese quail (Coturnix coturnix japonica). The transition from LD 16:8 to LD 8:16 was accomplished by symmetrical prolongation of the dark period. In LD 16:8, the period of elevated nocturnal activity lasted approximately 7 hours. During the first prolonged night, the evening N-acetyltransferase rise advanced by almost 3 hours relative to the rise in LD 16:8 and occurred at the same time as during the 3rd, 7th, and 14th day after the transition. The morning N-acetyltransferase decline did not shift during the first long night; during the third night it was delayed relative to the decline in LD 16:8 by more than 2 hours and occurred at the same time as during the 7th and 14th night following the LD 16:8 to LD 8:16 transition. Three, 7, and 14 days after the transition, the period of elevated N-acetyltransferase activity lasted approximately 12 hours. Hence extension of the N-acetyltransferase rhythm profile proceeded first into the evening and then only into the morning hours, and it was accomplished within 2 to 3 days.

Acetyltransferases↗
PubMed1986

Testosterone concentration in the seminal plasma of cocks.

Testosterone concentrations in the seminal plasma of cocks ranged from 0.46 to 5.05 ng/ml and were substantially lower than in blood plasma. No significant variation was noted in seminal plasma testosterone concentrations during the light phase of the day, whereas the concentration in blood declined over this period. Spermatozoal concentration and seminal testosterone decreased in the third sample of the semen collected sequentially at 3 h intervals. Testosterone concentrations in seminal plasma (1.57 +/- 0.17 ng/ml) and in the semen from the ductus deferens (1.34 +/- 0.24 ng/ml) were not significantly different.

Animals↗
PubMed1986

[Sexual development and levels of plasma testosterone in the light type of cockerel].

The concentration of testosterone in blood plasma during the ontogenetic development of cockerels was studied in relation to the development of spermatogenic part of gonads. On the basis of the results, sexual development of cockerels can be divided into three stages. The first stage (from hatching to the age of eight to nine weeks) was characterized by a slow increase in gonad weight, by low concentration of plasma testosterone (0.4-2.0 nmol/l) and by the occurrence of spermatogonia in testes. In the course of the second stage (from the age of nine to 16 weeks) a rapid increase in the weight of testes and testosterone concentration was observed. At the end of this stage all phases of spermatogenic cycle were observed in gonads; the testosterone levels averaged to 10 nmol/l. In the course of this stage all cockerels reached sexual maturity; large individual differences in spermatogenesis development were observed. The third stage (16 weeks of age and more) was characterized by an intensive spermatogenesis, further increase in gonad weight and by typical variations of the plasma testosterone levels. The concentration of the circulating testosterone increased before the onset of the final stages of the spermatogenic cycle.

Animals↗