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Biomedical subjects

H Gustafsson

Publications and source records attributed to H Gustafsson.

At least 91 records · Page 5Linked to original sources
PubMed1994

Cell kinetics of head and neck squamous cell carcinomas. Prognostic implications.

Forty-three squamous cell carcinomas of the head and neck region were in vivo labelled with the thymidine analogue iododeoxyuridine. Combined flow cytometric (FCM) and immunohistochemical (IHC) analysis was performed, and the following parameters calculated: labelling index (LI), S-phase time (TS) and potential tumor doubling time (Tpot). Complete FCM and IHC analyses could successfully be performed in 31 cases, showing a median LI of 13.6% with FCM and 9.1% with IHC. A correlation achieved between LI/FCM and LI/IHC was due to the aneuploid cases, whereas the diploid cases showed no such correlation. Data indicated that Tpot calculated with LI from IHC (Tpot/IHC) might be a prognostic factor, in contrast to Tpot determined using LI/FCM.

Adult↗
PubMed1994

Viability of fresh and frozen-thawed biopsied bovine embryos.

Bovine embryos were biopsied using a simplified splitting technique and frozen-thawed according to a standard method with glycerol as cryoprotectant. The viability of fresh and frozen-thawed biopsied and intact embryos were evaluated after in vitro culture, by means of fluorescence test or following transfer to recipients. The survival rates after in vitro culture of fresh intact and biopsied embryos and of frozen-thawed intact and zona free embryos were not significantly different (70%, 60%, 68% and 52%, respectively), but significantly reduced for biopsied frozen-thawed embryos (16%) (p < or = 0.05). The pregnancy results after transfer of biopsied frozen-thawed embryos were also significantly lower (8%) compared to fresh biopsied embryos (39%) (p < or = 0.05). Both intact and biopsied embryos fluoresced after incubation with diacetylfluorescin but with higher intensity for the intact embryos. It is suggested that the reduced survivability for the frozen-thawed biopsied embryos might be caused by combined effects of the loss of the zona pellucida and the reduction of cells as a result of the simplified biopsy technique. It is concluded that improved biopsy and/or freezing techniques must be used if biopsied embryos have to be frozen.

Animals↗
PubMed1994

Survival rate and ultrastructure of vitrified bovine in vitro and in vivo developed embryos.

The capacity of different vitrification media and methods was tested onto in vivo and in vitro produced bovine morula/blastocysts and their ultrastructure and survival studied post-thawing. Two vitrification solutions were finally selected, named 40 ES (40% ethylene glycol in PBS containing 0.5 M sucrose) and 35 EFS (composed of 35% (v/v) ethylene glycol in PBS containing 0.5 M/l sucrose and 30% (w/v) Ficoll 70). The straws were either precooled or not precooled in nitrogen vapour, plunged and stored in LN2 for 10-25 days, and then thawed in a 20 degrees C waterbath. The content of the straws was rediluted in 1M sucrose solution in PBS and later cocultured with BOEC for 48 h. The overall survival rates for in vitro and in vivo embryos were 36% (12 of 33) and 20% (3 of 15) after 24 h and 21% (7 of 33) and 33% (5 of 15) after 48 h. The survival rates for precooled embryos were significantly higher than for not precooled (48% vs 13% after 24 h and 44% vs 4% after 48 h) when tested across vitrification media. The in vitro-produced embryos presented an ultrastructure similar to the pre-freeze state, irrespective of the vitrification media used. The in vivo developed embryos showed a rather modified post-thaw ultrastructure, with clear signs of osmotic changes at both the trophoblastic and embryonic cells. The results indicated that in vitro and in vivo developed bovine embryos can survive vitrification using ethylene glycol as a cryoprotectant.

Animals↗
PubMed1993

Structural changes in the middle ear tissues of the rat after fractionated irradiation.

Chronic suppurative otitis media often ensues in patients treated with irradiation against a head and neck tumor. In an experimental study, rats were exposed to irradiation to evaluate the sensitivity of the middle ear to an accumulated irradiation dose of 20-45 Gy. Observed otomicroscopically, all animals appeared to have normal tympanic membranes and no fluid developed in the middle ear space. Ten days after the irradiation, minor structural changes had occurred in the pars flaccida. The keratinizing epithelium had thickened and mitoses were seen histologically. The lamina propria was edematous and contained polymorphonuclear cells and macrophages. The middle ear mucosa from all other tissue sites appeared normal. Six months after irradiation only minor changes in the pars flaccida were evident: the lamina propria was thin and inelastic and macrophages were present in the stroma. It is inferred from this study that the middle ear of the rat is relatively resistant to irradiation.

Animals↗
PubMed1993

Irradiation-induced effects on the innervation of rat salivary glands: changes in enkephalin- and bombesin-like immunoreactivity in ganglionic cells and intraglandular nerve fibers.

When treating head and neck for cancer with the use of radiotherapy the salivary glands are usually within the treatment volume with ensuing dryness and discomfort. Since the autonomic nervous system is of pivotal importance for the salivary gland function and integrity, the irradiation-induced effects may involve an influence on the innervation of salivary glands. Therefore, the rat submandibular gland, including the submandibular ganglionic cells, has been subjected to immunohistochemical examination with respect to expression of neuropeptides following fractionated irradiation with high energy photons. A markedly enhanced expression of bombesin- and leu-enkephalin-(ENK)-like immunoreactivities (LI) in the ganglionic cells and a pronounced increase in the number of nerve fibers showing these immunoreactivities in the submandibular gland tissue following irradiation were observed 10 days after treatment. On the other hand, no changes in the patterns of VIP (vasoactive intestinal polypeptide)- and NPY (neuropeptide Y)-immunoreactivities occurred. Thus, the present study shows that alterations in the expression of certain neuropeptides take place in the submandibular gland and its associated ganglionic cells in response to irradiation of the head and neck region. These changes may add further explanation to the inherent radiosensitivity of salivary glands.

Animals↗
PubMed1993

In vitro development up to hatching of bovine in vitro-matured and fertilized oocytes with or without support from somatic cells.

To verify the importance of somatic cells upon in vitro embryo development, in vitro-matured (IVM) and -fertilized (IVF) bovine oocytes were cultured in TCM 199 supplemented with estrous cow serum (10% v/v) and 0.25 mM sodium pyruvate (ECSTCM) under the following treatments: 1) ECSTCM alone; 2) together with bovine oviduct epithelial cells (BOEC); 3) with cumulus cells (CC); 4) in fresh BOEC conditioned ECSTCM; or 5) in frozen-thawed BOEC conditioned ECSTCM. Culturing zygotes encased in cumulus cells significantly reduced the cleavage rate (P<0.05). There was no difference between culture systems in the proportions of embryo development through the 8-cell stage (P=0.42) up to the morula/blastocyst stages (P=0.50) at Day 7 post insemination. However, co-culture with BOEC yielded the highest percentage (21.2% of zygotes; P<0.05) of quality Grade-1 and Grade-2 embryos with the number of blastomeres per embryo (114.4) comparable to that of 7-day-old in vivo-developed embryos of similar grades (102.5), and higher (P<0.05) than those of the other treatments. The ratio of blastocysts to total morulae/blastocysts obtained from frozen-thawed conditioned medium was lower (P<0.05) than that from ECSTCM or after co-culture with BOEC at Day 7 post insemination. On average, 7.5 to 17.5% of the zygotes developed to blastocyst, expanded blastocyst and hatched blastocyst stages by Day 10 post insemination, depending upon the culture system. The difference between treatments, however, was not significant (P=0.68). The results indicate that chronological development up to hatching of bovine IVM-IVF embryos is not favored by somatic cells; however, the presence of viable oviduct epithelial cells in culture significantly improves the quality of 7-day-old embryos.

Journal Article↗
PubMed1993

Fractionated irradiation and late changes in rat parotid gland: effects on the number of acinar cells, potassium efflux, and amylase secretion.

Irradiation of head- and neck cancer commonly results in oral dryness and discomfort for the patients due to salivary gland damage. The exact mechanisms behind the inherent radiosensitivity of salivary glands remain to be elucidated. In the present study, we used different in vitro secretory models and quantitative morphological characterization of rat parotid gland following fractionated unilateral irradiation to one gland on a 5-day fraction schedule (Monday-Friday) with 6 MV photons (total dose 30, 35, 40 and 45 Gy) or a two-fractions regimens in 5 days (Monday and Friday) with total dose of 24 and 32 Gy. The contralateral shielded gland served as control, and parallel analyses of irradiated and control glands were performed 180 days following the last irradiation treatment. The relative noradrenaline stimulated electrolyte secretion (86rubidium tracer for potassium) was decreased in the irradiated compared with control glands. The noradrenaline-stimulated exocytotic amylase release was not significantly affected by irradiation, but the gland content of amylase was decreased dose-dependently. The quantitative morphological analysis revealed a dose-dependent decline in the number of acinar cells, whereas the other parenchymal cells (intercalated, striated- and excretory duct cells) were unaffected by the irradiation compared with control glands.

Amylases↗
PubMed1993

Rhythmic contractions of isolated small arteries from rat: influence of the endothelium.

Small arteries of the mesenteric arcade from Wistar rats display rhythmic oscillations superimposed on the tonic contractile response when exposed to submaximal doses of noradrenaline. We have previously shown that mechanical removal of the endothelium abolishes these oscillations. In the present study different methods to eliminate or modify the influence of the endothelium were used in order to further characterize the mechanisms behind rhythmic contractions in these vessels. Endothelium was removed either mechanically or chemically by perfusing the vessels with 0.3% CHAPS. The absence of functional endothelium enhanced noradrenaline sensitivity and simultaneously abolished oscillations in tension and membrane potential, but did not affect resting membrane potential. The rhythmic activity was also reduced or abolished by exposure to haemoglobin, methylene blue, LY83583 or L-NNA. Indomethacin and propranolol were without effect. Sodium nitroprusside or the permeant analogue of cyclic GMP, 8-bromo cyclic GMP, restored rhythmic activity in precontracted endothelium-denuded vessels. The data suggest that release of nitric oxide from the endothelium, and subsequent generation of cyclic GMP in the smooth muscle, activates oscillations in membrane potential and tension; the oscillator itself appears to be located within the smooth muscle cells.

Aminoquinolines↗
PubMed1993

Rhythmic contractions of isolated small arteries from rat: role of calcium.

In order to investigate the mechanisms behind rhythmic contractions in small arteries of the mesenteric arcade from Wistar rats, the calcium dependency of the oscillations in response to noradrenaline activation was tested on isolated vessels. Application of 1 microM ryanodine or 30 microM TMB-8 (procedures known to inhibit Ca2+ release from intracellular stores) totally abolished the rhythmic activity, even though the antagonists had opposite effects on the amplitude of the contractile response to noradrenaline. Verapamil (1 microM) or felodipine (1 nM) (agents known to inhibit influx of extracellular Ca2+) also abolished the oscillations and reduced the maximal noradrenaline response by about 40%. Reducing the extracellular Ca2+ concentration to 0.1 mM reduced the amplitude of the noradrenaline response to a similar extent as 1 nM felodipine, but did not eliminate the oscillations. This may indicate that the effect of calcium entry blockers was to eliminate the voltage-dependency of Ca2+ inflow rather than just reducing the Ca2+ level. Manoeuvres that would increase the cytosolic Ca2+ concentration (exposure to caffeine or to the calcium agonist BAY-K 8644) increased the frequency of the oscillations. These observations indicate an important role, not only for voltage-operating channels, but also for intracellular calcium stores in the generation of rhythmic contractions in these small arteries. Oscillations appear to be generated by an interplay between membrane activation and intracellular calcium stores.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1993

Vasomotion and underlying mechanisms in small arteries. An in vitro study of rat blood vessels.

Arteries from many vascular beds display vasomotion, i.e. rhythmic oscillations superimposed on a tonic contraction. Vasomotion has been studied for more than hundred years, but the underlying mechanisms are still not fully understood; they may even differ between vascular beds. The aim of this study was to characterize the elements and mechanisms behind vasomotion in mesenteric small arteries from rat. Isolated arteries displayed vasomotion when contracted by noradrenaline, both under isometric and pressurized conditions. The frequency (12-16 cpm) was not dependent of agonist concentration, but showed a tendency to reduce at low transmural pressures. The amplitude was maximal at half-maximal contraction and was inversely correlated to transmural pressure. The tension oscillations were associated with corresponding oscillations in membrane potential and are known to be associated with oscillations in intracellular Ca2+ concentration. The endothelium was essential for vasomotion, apparently by increasing smooth muscle cyclic GMP via the release of nitric oxide. Cyclic GMP seemed to have a permissive role for a pacemaker located in the smooth muscle cell. The influence of transmural pressure on vasomotion was also located at the smooth muscle level. Upon reduction of extracellular Ca2+, vasomotion continued as long as a tonic contraction was obtained. In contrast, pharmacological blockade of voltage-operated Ca2+ channels (VOCs) totally abolished vasomotion, even though a sustained contraction was still obtained. Inhibition of the handling of Ca2+ in the sarcoplasmic reticulum (SR) abolished the oscillations while facilitating Ca2+ release with caffeine increased the frequency. Thus, both VOCs and the SR are essential in generation of vasomotion. The findings in the present work did not support either K+ channels or Cl channels to be directly involved in the feedback system of oscillation, although some K(+)-channels had a modulating influence. However, vasomotion was immediately abolished when the electrogenic effect of the Na+,K(+)-ATPase was inhibited by ouabain. The present data indicates that vasomotion was eliminated even when the Na+,K(+)-ATPase activity was only partly reduced. It also suggests that the activity of Na+,K(+)-ATPase might be regulated by the extracellular Na+ concentration. Based on the present results, a model for the generation of vasomotion in rat mesenteric small arteries is proposed. Vasomotion is generated via an endothelium-dependent feedback system in the vascular smooth muscle. Release and uptake of Ca2+ by the SR causes changes in sub-membrane Ca2+ concentration, which modulate the (electrogenic) activity of the Na+,K(+)-ATPase. The subsequent changes in membrane potential modulate the activity of VOCs and the ensuing changes in Ca2+ inflow feed back on the SR.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Bilateral irradiation of head and neck induces an enhanced expression of substance P in the parasympathetic innervation of the submandibular gland.

Substance P and calcitonin gene-related peptide (CGRP) are present in nerve fibers innervating the submandibular gland. Radiotherapy of tumors in the head and neck region usually embraces the salivary glands in the irradiated field and consequently a dramatic decrease in salivary function is seen. In this study, the submandibular glands and ganglia of rats subjected to fractionated irradiation were examined by use of immunohistochemical techniques for demonstration of substance P and CGRP. Irradiation was given on five consecutive days (daily doses of 6-9 Gray) with unilateral or bilateral irradiation techniques. Specimens of control and experimental animals were processed in parallel. A marked increase in the expression of substance P in the ganglionic cells--presumably parasympathetic--and in the number of fibers showing substance P-like immunoreactivity in association with acini and small ducts was seen in response to bilateral irradiation. (Surprisingly, unilateral irradiation of the parotid area had no effect on peptide distribution in the irradiated gland and ganglion). No changes in the pattern of CGRP immunoreactivity occurred. In the trigeminal ganglion, which supplies the submandibular gland with the majority of the sensory substance P- and CGRP-containing nerve fibers, no changes in the expression of substance P or CGRP immunoreactivity were seen. The results suggest that bilateral irradiation leads to an increase in the synthesis of substance P-like substance in the parasympathetic ganglionic cells supplying the submandibular gland with secretory nerves, and can thus be an additional factor in explaining the altered secretory capacity of salivary glands.

Animals↗
PubMed1992

Fine structure of corpora lutea in superovulated heifers.

The aim of the present study was to determine the degree of development and structural status of perfusion-fixed day-7 corpora lutea (CL) (using qualitative and quantitative histology at light and electron microscopy levels) in FSH-induced superovulated (SO) and untreated heifers. Blood samples were collected daily to monitor the plasma progesterone levels during the FSH treatment up to slaughter 7 days after oestrus. Meanwhile the ovarian activity was followed by ultrasonography and rectal palpation. At slaughter, the ovaries were fixed by vascular perfusion to avoid distortion of the structures and conventionally processed for electron microscopy. The volume density of the luteal tissue was calculated on the examined sections by point-counting. The histology of the corpora lutea, exception made of a higher incidence of degenerated luteal and endothelial cells in the superovulated animals, did not differ from that of the untreated animals, confirming their normal development. The mean weight and volume of the CL in SO animals was 50% smaller than that of the untreated heifers. The progesterone concentration (nmol/l) at day 7 was significantly positively correlated with the number of CLs/heifer (r = 0.93, P less than 0.01), with the weight of Cls/heifer (r = 0.97, P less than 0.005) and with the volume of CLs/heifer (r = 0.97, P less than 0.005). The results indicated that there were no morphological differences, in terms of histological structure and volume density, between the luteal tissue of SO heifers and the luteal tissue of non-SO heifers on day 7 of the oestrous cycle which could interfere with its endocrine function.

Animals↗
PubMed1992

Profiles of oestradiol-17 beta and progesterone and follicular development during the reproductive season in mink (Mustela vison).

Plasma concentrations of oestradiol-17 beta and progesterone were studied in yearling mink females. The blood samples were collected from 2 March until 13 April in females not subjected to mating and in females mated on two consecutive days, early or late in the breeding season, or with 8-9 days between matings. Peaks in oestradiol-17 beta were recorded on the day of first mating, in relation to the second wave of growing follicles, and in early April, around the time when implantation should have occurred. Significant rises in progesterone were recorded from 17 to 21 March and were slightly later in females mated late in the season. Histological studies of ovaries from unmated females revealed that the number of 'active' follicles exceeded the number of degenerated or luteinized follicles until 7 April, after which the number of degenerated follicles increased rapidly. Degeneration was followed by luteinization. On 15 April, ovaries were collected from two females having 15 luteinized follicles each. These females had increased plasma concentrations of progesterone. These studies indicate that, in female mink, peaks in oestradiol-17 beta coincide with the first mating as a result of the copulatory act and that unmated females appear to experience a luteal phase in the absence of ovulation.

Animals↗
PubMed1992

Different effects of fractionated irradiation on potassium efflux and exocytotic amylase release.

Irradiation of head-neck cancer influences the salivary glands with dryness and discomfort for the patients as a consequence. In the present study we used in vitro secretory models and morphological characterization of rat parotid gland. Irradiation was given as a 5-day schedule with total doses from 20 Gy to 45 Gy. Electrolyte secretion (86Rb as indicator for potassium) caused by noradrenaline was decreased in correlation to irradiation dose delivered compared to controlateral control glands 10 days following irradiation. Noradrenaline stimulated exocytotic amylase release was not at all affected, and there were no signs of quantitative morphological alterations following irradiation compared to control glands. The results indicate that there are differences in radiation sensitivity for the two different secretory processes in the salivary glands; the structures regulating electrolyte and fluid secretion seem to be more vulnerable to irradiation than those regulating exocytosis.

Amylases↗
PubMed1992

Fractionated irradiation and early changes in noradrenaline induced potassium efflux (86Rb+) in rat parotid gland.

The effects of fractionated irradiation on the electrolyte fluid secretion from rat parotid gland were studied. Secretion was measured as noradrenaline stimulated potassium efflux in vitro with 86Rb+ as tracer for potassium. The irradiation was delivered either as a five-day schedule (total dose 20, 25, 30, 35, 40, 45 Gy) or a two-day schedule (total dose 24, 32 Gy). The noradrenaline stimulated efflux was decreased in comparison with contralateral controls 10 days after the last irradiation. The effect was dose-dependent. Based on the data available, alpha/beta ratio of the used system was calculated to about 20 Gy, which corresponds to other results regarding early radiation effects.

Animals↗