Biomedical subjects

A Krieger

Publications and source records attributed to A Krieger.

15 recordsLinked to original sources

PubMed1992

Management of traumatic optic neuropathy--a study of 23 patients.

Twenty three patients with traumatic optic neuropathy were managed by medical and surgical treatment as follows. High dose intravenous steroids were initiated in all patients. If visions did not improve significantly after 24 to 48 hours decompression of an optic nerve sheath haematoma by medial orbitotomy and neurosurgical decompression of the optic canal were considered based on computed tomographic scan findings. Nine of 16 patients who received steroids only showed significant improvement. One of three showed improvement on optic nerve decompression after steroid failure; three or four showed improvement on optic nerve decompression after steroid failure; three or four showed improvement with combined optic nerve sheath decompression by the medial orbitotomy and decompression of the optic canal by frontal craniotomy. A lucid interval of vision after injury and an enlarged optic nerve sheath were associated with an improved prognosis. Five of the 23 patients had a lucid interval and all five had a final improved vision, while only five of 18 patients without a lucid interval improved. Similarly seven of the nine with an enlarged optic nerve sheath showed improvement while only three of 10 patients (three bilateral cases) who presented with no light perception improved with medical and surgical treatment. While a prospective controlled study of the management of traumatic optic neuropathy is necessary this preliminary study suggests that treatment of traumatic optic nerve sheath haematoma by optic nerve sheath decompression should be considered in selected patients.

Adolescent↗

PubMed1992

[Pilot study of dose dependence in glucuronidation of morphine to morphine-3- and morphine-5-glucuronide].

In the capacity of an initial study both, the half-lives of morphine and its metabolites morphine-3-glucuronide and morphine-6-glucuronide as well as the ratio of concentrations in the development of time using two different dosages were determined and shown by comparison. A bolus of 10 mg (10 micrograms) tritium-marked morphine was administered intravenously. Subsequently the half-lives of morphine, morphine-3-glucuronide and morphine-6-glucuronide in serum, saliva and urine were determined. To achieve this, morphine and its glucuronides were separated via HPLC and then quantified by measuring the radioactivity. In addition to the short half-lives of morphine and morphine-glucuronides long half-lives were found in the range of 12.6 to 20 hours in serum and urine. There was no positive evidence for glucuronides in saliva. In urine the morphine/glucuronide ratio showed a linear resp. exponential development dependent of dose.

Adult↗

PubMed1990

Relative effects of different spinal autonomic nuclei on cardiac sympathoexcitatory function.

Mean arterial pressure and heart rate were monitored in immobilized and artificially ventilated male Wistar rats either anesthetized with pentobarbital or decerebrated at midcollicular level. The rate of increase in the left ventricular pressure was also monitored in order to compute contractility index. L-glutamate (1.77 nmole) was microinjected (10 nl) into the following autonomic nuclei of the spinal cord at C8 to T4 levels: 1) intermediolateral column (IML), 2) n. intercalatus spinalis (IC) and 3) n. intercalatus pars paraependymalis (ICpe); this region is commonly known as the central autonomic area (CA). The site of microinjection was marked by injection of a dye; these studies suggested that microinjections of glutamate into the IML are likely to encompass the neurons in the nucleus (n.) intermediolateralis thoracolumbalis pars principalis (ILp) and n. intermediolateralis thoracolumbalis pars funicularis (ILf). Sympathoexcitatory cardiac responses to glutamate microinjections were elicited from T1 to T3 levels; these responses could not be evoked at C8 and T4 levels. In each of these segments, maximum responses were obtained from the IML while the responses evoked from the IC and the CA were minimal. These results suggest that at T1 to T3 levels of the spinal cord, IML is the main cell group regulating sympathetic cardiac function; CA and IC may play a relatively minor role in this function.

Adrenergic Fibers↗

PubMed1989

Microinjections of cholinergic agonists into the intermediolateral cell column of the spinal cord at T1-T3 increase heart rate and contractility.

Cardiovascular responses to the microinjections of cholinergic agonists into the intermediolateral cell column (IML) of the spinal cord at T1-T3 level were studied. Mean arterial pressure (MAP), heart rate (HR), the rate of increase in the left ventricular pressure (dp/dt) and contractility index (CI) were monitored in immobilized and artificially ventilated male Wistar rats either anesthetized with pentobarbital or decerebrated at mid-collicular level. Microinjections (20 nl) of carbachol (110-660 pmol) into the right IML elicited a marked increase in HR and a small increase in CI. A marked increase in the CI with relatively little effect on the HR was observed when carbachol was injected into the left IML. The cardioacceleratory effects of carbachol, but not those of L-glutamate, were blocked by prior microinjections of scopolamine (18 nmol) into the IML. Intravenous injections of chlorisondamine (a ganglion blocker) also blocked these effects of carbachol. Spinal transections at C4 or T6 level did not alter these responses. Microinjections of acetylcholine (0.01-1 nmol) into the right IML also produced tachycardic effects. The responses to acetylcholine were blocked by prior injections of a muscarinic receptor blocker (atropine hemisulfate, 0.2 nmol). Microinjections of a selective M2 muscarinic receptor agonist, cis-methyldioxolane (CD; 0.2-0.8 nmol), but not those of a relatively selective M1 receptor agonist (McN-A343; 2-3 nmol), into the right IML elicited an increase in HR. Previous microinjections of a selective competitive M2 receptor antagonist (AFDX-116; 0.8 nmol), but not those of a potent selective M1 receptor antagonist (pirenzepine; 2 nmol), into the IML blocked the effects of CD. Nicotine (0.25-1 nmol) when injected into the right IML also produced positive chronotropic effects. These responses were blocked by prior microinjections of hexamethonium (5 nmol). The above-mentioned results suggest that cholinoceptive neurons, interneurons or terminals are located in the areas of IML which control cardiac functions. Muscarinic as well as nicotinic receptors are present in this area. Muscarinic receptors are predominantly of the M2 type. The physiological significance of the presence of cholinergic receptors in this area in controlling cardiac functions remains to be established.

Acetylcholine↗

PubMed1989

Electrolytic lesions in the depressor area of the ventrolateral medulla of the rat abolish depressor responses to the aortic nerve stimulation.

The pressor (VLPA) and the depressor (VLDA) areas in the ventrolateral medulla were identified with the microinjections of L-glutamate (1.77 nmol/site) in artificially ventilated, pentobarbital-anesthetized male Wistar rats. Electrical stimulation of the left or right aortic nerve (1-6 V, 10-40 pulses/s, 3 ms) produced usual depressor responses. Electrolytic lesions (2.5 mA for 30 s) were placed bilaterally in the VLDA. Lack of responses to subsequent microinjections of glutamate into the VLDA indicated that the lesions were complete. The function of the VLPA was not compromised because it continued to respond to microinjections of glutamate. Subsequent stimulation of the aortic nerves failed to elicit the usual depressor responses. These results confirm our earlier reports indicating that the VLDA is important in mediating the depressor component of the aortic baroreflex.

Animals↗

PubMed1986

Human axillary secretions influence women's menstrual cycles: the role of donor extract from men.

Menstrual cycle lengths of 29.5 +/- 3 days ("normal cycles") are more frequent in women who have weekly coital activity than in women who do not. In order to investigate potential mechanisms controlling the association between heterosexual activity and menstrual cycle length, and in light of the nonhuman literature suggesting that a chemical signal from males could be involved, menstrual cycle lengths of nulliparous women were evaluated following regular application of axillary extract from donor males. Compared to controls receiving only blank/ethanol applications, women receiving axillary extracts for 12.5 to 14.5 weeks showed the following changes: a reduced incidence in variability of cycle lengths; and a reduced proportion of aberrant length cycles.

Adult↗

PubMed1983