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Biomedical subjects

C Goetz

Publications and source records attributed to C Goetz.

At least 19 recordsLinked to original sources
PubMed1991

[Hardware for graphics systems].

In all personal computer applications, be it for private or professional use, the decision of which "brand" of computer to buy is of central importance. In the USA Apple computers are mainly used in universities, while in Europe computers of the so-called "industry standard" by IBM (or clones thereof) have been increasingly used for many years. Independently of any brand name considerations, the computer components purchased must meet the current (and projected) needs of the user. Graphic capabilities and standards, processor speed, the use of co-processors, as well as input and output devices such as "mouse", printers and scanners are discussed. This overview is meant to serve as a decision aid. Potential users are given a short but detailed summary of current technical features.

Computer Graphics↗
PubMed1990

A comparative analysis of THAM (Tris-buffer) in traumatic brain oedema.

The effect of THAM on brain oedema parameters was initially investigated in animals with cold brain lesions; THAM was then used in head injury patients, ICP, SAP and CPP were analyzed. In the experiments with rats after freezing lesion, THAM was compared to equivalent doses of Na-bicarbonate. The animals were artificially respirated and sacrificed 6 h after trauma. THAM did significantly reduce water (wet-dry weight technique) and sodium contents in both hemispheres, whereas bicarbonate was ineffective. The potassium contents were even preserved at almost normal levels. In 80 patients receiving alternatively THAM (18-36 g/100-200 ml/1-2h), mannitol (20%, 125-250 ml/20-40 min) or sorbitol (40%, 70-140 ml/20-40 min), the ICP rapidly decreased following THAM infusion. The maximal fall in ICP (33%) was equal to that with mannitol and sorbitol. The slope of ICP decrease was equal with THAM and Mannitol but steeper with sorbitol. With THAM, however, the effect on ICP lasts longer than with osmotherapy. The EEG improved more rapidly after THAM. As shown by blood plasma values, the action of THAM is not based on osmotic effects. The increases in pH and especially in base excess suggest an intracerebral buffering. The encouraging results with THAM require a randomized clinical trial after severe head injury which is presently prepared.

Adolescent↗
PubMed1990

[The foramen of Monro--blockage caused by a giant aneurysm of the basilar artery. A case report and review of the literature].

A case of a giant aneurysma of the basilar artery bifurcation with occlusive hydrocephalus due to bilateral foramen of Monro occlusion is reported. The patient presented with progressive neurological deterioration which led to computerized tomography examination and implantation of a ventricular shunt as an emergency procedure. After the patient had recovered to a certain extent, four-vessel angiography was performed that demonstrated a giant basilar tip aneurysm. As the posterior communicating, the posterior cerebral as well as the superior cerebellar arteries originated from the aneurysm sac direct surgical attack as well as endovascular treatment was considered to be impossible. A permanent biventricular-abdominal shunt system was implanted and the patient was discharged. Three weeks later the patient was readmitted comatose after he had suffered a massive subarachnoid hemorrhage from which he finally died. The clinical and radiological signs, the differential-diagnostic considerations as well as the few cases of foramen of Monro occlusion by a giant basilar artery tip aneurysm, presented in the literature so far, are discussed.

Basilar Artery↗
PubMed1990

Variable expression of Parkinson's disease: a base-line analysis of the DATATOP cohort. The Parkinson Study Group.

The DATATOP database, which includes clinical information on 800 patients with early untreated Parkinson's disease (PD), is well suited to explore clinical heterogeneity in PD. Patients with early-onset PD (less than or equal to 40 years, N = 33) reached the same level of disability as the late-onset PD (greater than or equal to 70 years, N = 85) group at a significantly slower rate (2.9 vs. 1.7 years). Early-onset PD patients functioned cognitively better than late-onset PD patients. Bradykinesia, and postural instability and gait difficulty (PIGD), were more common at onset in patients with a rapid rate of disease progression ("malignant PD"; duration of symptoms less than 1 year and Hoehn/Yahr stage of 2.5, N = 11) as compared with those with a relatively slow rate of progression ("benign PD"; duration of symptoms greater than 4 years, N = 65). Comparisons of tremor-dominant PD (mean tremor score/mean PIGD score less than or equal to 1.5, N = 441) with the PIGD-dominant type (mean tremor score/mean PIGD score greater than or equal to 1.0, N = 233) provided support for the existence of clinical subtypes. The PIGD group reported significantly greater subjective intellectual, motor, and occupational impairment than the tremor group. Stage II patients had higher depression scores than stage I patients. Among the patients participating in the DATATOP, older age at onset with bradykinesia, or with the PIGD form of PD, is associated with more functional disability than when the symptoms are dominated by tremor or begin at a younger age.

Adult↗
PubMed1990

[Microsurgery, laser-assisted cranial nerve anastomosis. An experimental study].

Recently the milliwatt-CO2-laser has been introduced into the armentarium of experimental microsurgery for performing coaptation in peripheral nerves using the thermal effect of laser energy in order to achieve an atraumatic and reliable tissue bond. Experimental studies have shown that laser-assisted nerve coaptation are equal if not superior to conventional techniques in the reduced incidence of neuroma formation as well as the regenerative capacity. In this experimental study we have investigated if the CO2-laser working in the milliwatt range can be successfully applied for performing anastomosis of cranial nerves. The right oculomotor nerve in cats was microsurgically explored along the lateral temporal fossa from its exit at the brain stem to its entrance into the rudimentary cavernous sinus. Following division of the nerve with microscissors the nerve ends were loosely approximated. Thereafter welding of the cut nerves was performed with the CO2-laser (Cooper Laser Sonics, Model 860) using a power of 80-90 milliwatts, a spot-size of 150 microns and single bursts of laser energy. Complete welding of the cut nerve ends took about one to two minutes after which the surgical wound was closed. All experimental animals were observed for a period of 12 weeks after which they were sacrificed and the welded oculomotor nerve was removed for histological examination. Functional recovery of the III. nerve during the observation period was demonstrated by examination of the resting diameter of the pupil as well as by its reaction to direct stimulation with light. Morphological regeneration of the operated nerves could be demonstrated by histological studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1989

Efficacy of single intracisternal bolus injection of recombinant tissue plasminogen activator to prevent delayed cerebral vasospasm after experimental subarachnoid hemorrhage.

Premature lysis of subarachnoid blood clots by thrombolytic substances such as urokinase and plasmin has been shown to be efficacious in preventing cerebral vasospasm in clinical and experimental investigations. Recently, tissue plasminogen activator (rtPA) derived from recombinant deoxyribonucleic (DNA) technology has been introduced as a new thrombolytic substance. With its high affinity for fibrin-bound plasminogen and low affinity for circulating plasminogen by which a clot-selective fibrinolysis can be achieved without the danger of inducing systemic fibrinogenolysis, rtPA might be the ideal substance for the postoperative lysis of cisternal blood accumulations after subarachnoid hemorrhage. The efficacy of rtPA in preventing delayed cerebral vasospasm after experimental subarachnoid hemorrhage using a single intracisternal bolus injection of this agent was investigated. With a single injection of 25 micrograms of rtPA into the cisterna magna 48 hours after the first and 6 hours after the second injection of blood in the two-hemorrhage model of cerebral vasospasm, angiographic spasm of the basilar artery was completely prevented in all animals so treated whereas in the control group severe vasospasm occurred. Autopsy studies of the experimental animals demonstrated that the subarachnoid blood clots were almost completely removed by intracisternal rtPA application. Additionally the pathomorphological signs of proliferative vasculopathy present in all animals of the control group were not demonstrable in the rtPA group. As intracisternal bolus injection of rtPA is highly efficacious in preventing angiographic as well as pathomorphological vasospasm, it is concluded that use of this thrombolytic substance might be a promising approach for pharmacological blood clot removal.

Animals↗
PubMed1989

[Microcomputer systems in urology: hardware--mole's hole or useful equipment?].

The basic concepts and elements of micro- and minicomputer hardware components frequently used in urology are described. For advanced users, the details and trends are discussed in more detail. The interdependence of hardware and operating systems is emphasized. In addition, a method for the evaluation of personal computer performance is presented. Finally, proposals are made concerning purchasing procedures and selection criteria.

Humans↗
PubMed1988

Longitudinal development of specific and functional antibody in very low birth weight premature infants.

We evaluated the formation of specific and functional antibody in preterm infants born weighing less than 1500 g (mean 1088 g) and less than 32 wk gestational age (mean 28.8 wk). Plasma IgG antibody against tetanus and diphtheria toxoids were measured by an enzyme-linked immunosorbent assay. Opsonic activity of heat-inactivated plasma was measured using radiolabeled bacteria, adult polymorphonuclear leukocytes and exogenous human complement. In the presence of complement, the strain of coagulase negative staphylococcus used was opsonized by IgG antibody, and the strain of Escherichia coli by IgM. Geometric mean plasma levels of tetanus and diphtheria IgG antibody fell from birth to 4 months chronological age, but rose significantly by 9 months (approximately 2 months after the third dose of diphtheria, tetanus, pertussis vaccine). However, at 9 months they remained lower than the respective geometric mean levels in 9-month-old term infants (tetanus: p less than 0.001; diphtheria: p = 0.02). The preterm infants' mean plasma IgG staphylococcal opsonic activity fell from birth to 2.5 months, but by 9 months was comparable to that of term infants of the same age. Mean IgM opsonic activity for E. coli was very low at birth in both preterm and term infants. It rose with chronological age, correlating with the rise in total IgM (r = 0.48, p less than 0.001) and by 9 months the mean preterm and term infants' levels of IgM opsonic activity for E. coli were comparable.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody Formation↗
PubMed1987

Peripheral blood T-cell subpopulations in the very low birth weight (less than 1,500-g) infant.

The development of monoclonal antibodies to cell-surface antigens has provided method for characterizing distinct subpopulations of T-cells. In the present study we have quantified peripheral blood T-cell subpopulations in premature infants born weighing less than 1,500 g (1123 +/- 223 g) and ranging in gestational age from 25 to 32 weeks. The relative proportion of T4 cells in the very low birth weight (VLBW) infants was markedly higher at 1 week and 1 month of age (mean +/- SEM; 67.5 +/- 4.1 and 59.2 +/- 1.6) than in adult controls (47.2 +/- 1.5). The percentage of T4 cells remained elevated until 6 months of age, when it decreased to a level comparable to that in adults. In contrast, the proportion of T8 cells was significantly lower than the adult level at 1 week and 1 month of age. The T4/T8 ratio in the VLBW infants was higher at 1 week (4.3 +/- 0.5) and 1 month (3.5 +/- 0.2) than in adult controls (2.0 +/- 0.1). Thereafter, the T4/T8 ratio decreased but was still significantly higher than that in adult controls at 6 months of age (2.6 +/- 0.2). The absolute numbers of total T-cells (T3) and T8 and T4 cells were significantly higher in VLBW infants. The numbers of T8 cells were significantly lower in the first month of life than at 3-6 months of age. These alterations in the T-cell subsets in the first 6 months of life suggest that postnatal T-cell phenotypic changes in VLBW infants may parallel the T-cell ontogenetic process which occurs during the last trimester of pregnancy in full-term infants.

Blood Cells↗
PubMed1986

Development of the immune system in very low birth weight (less than 1500 g) premature infants: concentrations of plasma immunoglobulins and patterns of infections.

Plasma immunoglobulin concentrations of premature infants of birth weight less than 1500 g were measured longitudinally from birth to 10 months chronological age. Infants were divided into two groups based on gestational age (group I: 25-28 wk; group II: 29-32 wk). In the 1st wk of life, plasma IgG levels correlated with gestational age (r = 0.5, p less than 0.001). At 3 months chronological age, the geometric mean plasma IgG levels were 60 mg/dl in group I and 104 mg/dl in group II infants. Most infants remained hypogammaglobulinemic at 6 months with seven of 11 infants in group I and 13 of 21 infants in group II having plasma IgG levels below 200 mg/dl. In the 1st wk of life, plasma IgM concentrations were 7.6 and 9.1 mg/dl in groups I and II, respectively. They rose to 41.8 and 34.7 by 8 to 10 months of life. Plasma IgA concentrations were comparable for groups I and II in the 1st wk of life (1.2 and 0.6 mg/dl, respectively), but at 1 month of age group I infants had a transient increase in IgA which was not seen in the group II infants (4.5 versus 1.9 mg/dl, respectively, p less than 0.02). This transient elevation in IgA did not correlate with type or route of feeding or amounts of transfused blood. Group I and group II infants had comparable rates of infections prior to discharge from the nursery (p = 0.27). After discharge, the 43 preterm infants followed until 10 months chronological age had a significantly higher incidence of infections than 41 term infants (p = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1977

Clonazepam and 5-hydroxytryptophan-induced myoclonic stereotypy.

The effect of clonazepam on a behavioral model of increased whole brain serotonin activity was investigated. While clonazepam induces a moderate elevation of whole brain serotonin, the drug fails to potentiate or inhibit 5-hydroxytryptophan-induced stereotypy in young guinea pigs. These results suggest that despite drug induced alterations in serotonin concentration clonazepam does not hava an effect on the physiologic activity of serotonin and may not exert its pharmacologic activity by influencing serotonin within the brain.

5-Hydroxytryptophan↗
PubMed1975

Levodopa-induced myoclonus.

Twelve parkinsonian patients on long-term levodopa therapy developed intermittent, myoclonic body jerks. The movements consisted of single unilateral or bilateral abrupt jerks of the extremities and occurred most frequently during sleep. Although directly related to daily dosage of levodopa, the myoclonus was specifically blocked by the serotonin antagonist, methysergide. Levodopa-induced myoclonus may be related to intermittent increases of activity of serotonin in the brain and results from levodopa-induced dysregulation of serotonin activity.

5-Hydroxytryptophan↗