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Biomedical subjects

M Schultz

Publications and source records attributed to M Schultz.

At least 73 records · Page 4Linked to original sources
PubMed1995

Novel urinary metabolite of alpha-tocopherol, 2,5,7,8-tetramethyl-2(2'-carboxyethyl)-6-hydroxychroman, as an indicator of an adequate vitamin E supply?

Previously, the metabolism of alpha-tocopherol was considered to involve the opening of the chroman structure because of its oxidation to tocopherylquinone. In contrast, we describe here 2,5,7,8-tetramethyl-2(2'-carboxyethyl)-6-hydroxychroman (alpha-CEHC) as the major urinary metabolite of alpha-tocopherol that appears in human urine after vitamin E supplementation. It is formed directly from alpha-tocopherol without previous oxidative splitting of the chroman ring. The correlation of alpha-tocopherol intake, plasma alpha-tocopherol concentrations, and urinary excretion of alpha-CEHC in human volunteers supplemented with RRR-alpha-tocopherol dosages ranging from 0 to 800 mg/d was examined. HPLC and gas chromatography-mass spectroscopy analysis revealed that alpha-CEHC was only excreted when a plasma threshold of 7-9 mumol alpha-tocopherol/g total lipid was exceeded. This concentration was obtained by a daily intake of approximately 50-150 mg alpha-tocopherol. We suggest that alpha-CEHC excretion indicates a saturated binding capacity of vitamin E in the plasma and thus may be considered to be a marker of optimum vitamin E intake.

Biomarkers↗
PubMed1995

Microscopic haematuria as a relative contraindication for tranexamic acid.

Tranexamic acid has been advocated for patients with severe bleeding tendency due to thrombocytopenia not responding to platelet transfusions. Macroscopic haematuria is a well-known contraindication for its use in such patients. We present three clinical cases with microscopic haematuria, in whom tranexamic acid caused problems of clot formation in the urinary tract, indicating that microscopic haematuria should also be considered as a contraindication for tranexamic acid.

Adult↗
PubMed1995

Venous transcranial Doppler ultrasound monitoring in acute dural sinus thrombosis. Report of two cases.

BACKGROUND AND PURPOSE: We sought to establish the efficacy of the Doppler technique in the evaluation of the intracranial venous system and to assess its usefulness in the monitoring of venous collateral pathways in superior sagittal sinus thrombosis. METHODS: Venous Doppler ultrasound was performed with a range-gated 2-MHz transducer in 10 healthy volunteers and in two patients with superior sagittal sinus thrombosis confirmed by cerebral angiography. RESULTS: In normal control subjects, a venous signal was found at a depth ranging from 40 to 72 mm, which was considered to correspond to the deep middle cerebral vein and the basal vein of Rosenthal. Mean blood flow velocities ranged from 9 to 20 cm/s. In both patients with superior sagittal sinus thrombosis, Doppler studies detected elevated mean blood flow velocities (146 and 33 cm/s), which normalized after 16 weeks and 1 week, respectively. CONCLUSIONS: Venous transcranial Doppler ultrasonography provides a reliable, noninvasive, and rapid technique for intracranial venous examination. It was performed without difficulty in young health volunteers, and it can be applied as a monitoring tool in the evaluation of collateral venous flow in superior sagittal sinus thrombosis.

Acute Disease↗
PubMed1995

Targeted mutation of the murine goosecoid gene results in craniofacial defects and neonatal death.

The goosecoid gene encodes a homeodomain-containing protein that has been identified in a number of species and has been implicated in a variety of key developmental processes. Initially suggested to be involved in organizing the embryo during early development, goosecoid has since been demonstrated to be expressed during organogenesis-most notably in the head, the limbs and the ventrolateral body wall. To investigate the role of goosecoid in embryonic development, we have inactivated the gene by gene targeting to generate mice mutant for the goosecoid gene. Mice that are homozygous for the goosecoid mutation do not display a gastrulation phenotype and are born; however, they do not survive more than 24 hours. Analysis of the homozygotes revealed numerous developmental defects affecting those structures in which goosecoid is expressed during its second (late) phase of embryonic expression. Predominantly, these defects involve the lower mandible and its associated musculature including the tongue, the nasal cavity and the nasal pits, as well as the components of the inner ear (malleus, tympanic ring) and the external auditory meatus. Although the observed phenotype is in accordance with the late expression domains of goosecoid in wild-type embryos, we suggest that the lack of an earlier phenotype is the result of functional compensation by other genes.

Animals↗
PubMed1994

Cytologic atypia associated with microglandular hyperplasia.

Although it has long been known that microglandular hyperplasia (MGH) may be associated with cytologic atypia in cervical smears, the cytomorphology of MGH has not been described in great detail. To clarify its cytomorphology, Pap smears obtained from biopsy proven cases of MGH over a 3-yr period were reviewed. Of 122 smears containing endocervical cells, 34 (28%) showed striking glandular abnormalities. In two cases, adenocarcinoma and adenocarcinoma in situ were falsely suggested and a high grade squamous intraepithelial lesion (HGSIL-CIN III) was not confirmed in a conization specimen which showed only low grade SIL and MGH. Review of six cytologic diagnoses of HGSIL (CIN III) unconfirmed on biopsy suggested overcalls related to MGH related atypia in five. Cytologic features of MGH, therefore, may occasionally result in erroneous interpretations of HGSIL as well as glandular neoplasia. Although these changes may be striking, comparison with glandular atypia not associated with MGH shows that they are not entirely specific.

Adolescent↗
PubMed1994

The macroscopic and microscopic structure of double-head antlers and pedicle bone of cervidae (Mammalia, Artiodactyla).

Ortho- and heterotopically formed double-head antlers were studied in red, fallow and roe deer. The malformation was the result of new antler growth without previous casting of the old antlers. Thus, two antler structures belonging to successive antler generations originated from one pedicle. These two structures were always separated by a horizontal groove. Histologically, signs of osteoclastic resorption were observed in the interior and at the outer circumference of the distal parts of the pedicles of the double heads. The resorptive process had, however, not been of an intensity necessary for subsequent antler casting. We also observed that the double-head's second antler generation had developed as a periosteal exostosis of the distal pedicle bone. Thus, we assume that in normogenesis formation of the bony component of subsequent antlers is also probably dependent on cells derived from pedicle periosteum. Finally, the process of antler regrowth in deer is compared with epimorphic regeneration occurring in other vertebrates.

Animals↗
PubMed1993

Effects of an antiandrogen treatment on the antler cycle of male fallow deer (Dama dama L.).

Weekly application of the antiandrogen cyproteron acetate (CA) to 3 adult (group 1, treatment starting 3 weeks prior to the rut) and 4 subadult (group 2, treatment starting after the rut) fallow bucks led to premature antler casting after about 9 weeks (group 1) or 16 to 17 days (group 2). Variation in time span between onset of CA administration and induced casting (in late November/early December) is attributed to age- and season-dependent differences in androgen levels before and during the treatment period. Casting surfaces of the antlers were flat. In all bucks, casting was followed by a complete though shortened antler cycle, occurring under short day conditions. In February/March velvet was shed from the antlers, indicating a rise in plasma androgen levels at that time. At time of fraying, antlers exhibited signs of immaturity and were shorter than normal. In the most pronounced case of immaturity, the antlers consisted mainly of cancellous woven bone, revealing that bone remodeling and antler mineralization had not occurred to a larger extent. These observations prove that onset of fraying behaviour does not depend on prior maturation of antler bone or necrosis of velvet. Occurrence of the additional antler cycle in late autumn and winter had no negative effect on subsequent antler formation starting in the following spring.

Animals↗
PubMed1993

Bacterial ventriculitis and duration of ventriculostomy catheter insertion.

Invasive monitoring of intracranial pressure (ICP) plays an important role in managing many neurosurgical patients. While there are several techniques available to monitor ICP, the ventricular catheter is most commonly used and the most accurate. ICP monitoring poses potential risks to the patient. The most common and one of the most devastating complications is infection. This research study examined the rate of bacterial ventriculitis in relation to duration of ventricular catheter insertion as well as other factors which may contribute to ventriculitis. Data were collected prospectively on 78 patients with a ventriculostomy who were 14 years of age or older and admitted to the neuroscience intensive care unit. Patients were followed from the time of ventricular catheter placement to two weeks after the catheter was removed or until the patient was discharged from the hospital. A significantly higher ventriculitis rate was found in patients with a mean catheter duration of 11 days or longer (p = .004). In the group that developed ventriculitis there was a significant rise (means = 6.03592, p = .014) in the cerebrospinal fluid (CSF) lactate prior to the onset of ventriculitis. Neuroscience nurses should be aware of the factors which may increase the rate of ventriculitis, such as duration of catheter placement and factors which may indicate impending infection such as a rise in the CSF lactate. Future studies should compare various methods of ventriculostomy site care for efficacy of infection prevention, cost and caregiver time.

Adolescent↗
PubMed1993

[Results of surgical treatment and prognosis of colonic neoplasms complicated by perforation].

Twenty two patients (13 males), whose ages ranged between 25 and 94 years, were subjected to surgical treatment for perforative carcinoma of the colon in a period of 10 years. Seventy three percent of tumors were localized in rectum and sigmoid colon. The perforation lied within the tumor in half of the patients and proximal to the tumor, specially in the cecum, in the rest. The perforation produced a local abscess in 5 patients and a diffuse peritonitis in 17 patients. Fifteen patients were subjected to segmental resections with a 40% operative mortality rate and 5 to a fecal diversion procedure with a 57% operative mortality. Tumor staging was similar to that of patients subjected to elective surgery. Crude 5 year survival was 18% and, excluding operative mortality, 57%.

Adult↗
PubMed1992

Structure of the major oligosaccharide of cobra venom factor.

Cobra venom factor (CVF), the complement-activating glycoprotein in cobra venom, contains three or possibly four N-linked oligosaccharide chains per molecule and is devoid of O-linked saccharides. Analysis by lectin-affinity staining revealed the presence of complex-type oligosaccharides containing non-reducing terminal alpha-galactosyl residues and fucose residues linked to the proximal N-acetylglucosamine. Sialic acid residues could not be detected. For their structural analysis, the oligosaccharides were released by hydrazinolysis and fractionated on Bio-Gel P-4. Approximately 80% of the eluted oligosaccharides have a size equivalent of 17 +/- 2 glucose units. The major oligosaccharide representing about 45% of the total carbohydrate present in CVF was purified to homogeneity by MicroPak AX-5 HPLC and its structure was analyzed by sequential exoglycosidase digestion. The positions of the glycosidic linkages of the sugar residues were established by methylation analysis of CVF-derived glycopeptides. The data of these analyses indicated that the major oligosaccharide has a symmetrical fucosylated biantennary complex-type structure terminating with unusual alpha-galactosyl residues.

Animals↗
PubMed1992

[Colon and rectum cancer complicated with obstruction: immediate results and long-term follow-up].

Colorectal cancer is the leading cause of large bowel obstruction in Chile. The aim of this work was to assess the immediate results and long term survival of the surgical treatment of this complication. The clinical features of 113 patients (48 male and 65 female) with a mean age of 65 years, operated in a period of 10 years, were reviewed. The follow up was made by clinic appointments or home visits. The tumor was localized in the right colon in 30 cases, transverse colon in 20, splenic angle in 14, left colon in 39 and rectum in 10. Operative mortality was 34% for tumors of the right colon and 14% form tumors of the left colon. The follow up of the 89 survivors was accomplished in 97% with a mean follow up of 54 months (range 6 months-10 years). The principal prognostic factor was the initial stage of the tumor; survival was 87% for Dukes-Turnbull stage A, 70% for stage B and 32% for stage C1. The maximal survival period for stages D was 28 months. Patients subjected to an initial resective surgical procedure fared better, although not significantly, than colostomized patients. Present tendency is to perform one surgical procedure, avoiding colostomies that worsen patients quality of life and require a second intervention that increases surgical morbidity.

Adult↗
PubMed1992

[The problems of early diagnosis of diffuse malignant mesothelioma from the pathologo-anatomic view].

An account is given in this paper of particular problems associated with early detection of mesotheliomatous alterations and differential diagnosis for their distinction from reactive mesothelial cell proliferations. Reference is made, in that context, to pathologico-anatomic experience obtained from postmortem and biopsy samples of human malignant mesotheliomas and animal experiments, following exposure to various asbestos-containing dusts. Diagnoses, such as "premesotheliomatous alteration" or "early mesothelioma", in other words, differentiation between benign and malignant, consequently, appear to be unjustified.

Animals↗
PubMed1991

Patterns of early lexical and cognitive development in premature and full-term infants.

The linguistic and cognitive development of 26 premature and 27 full-term infants was studied longitudinally over the first 3 years of life. Infants in the premature population included 12 who were below 1500 g in birthweight and an even larger number with "at risk" signs. Language samples were collected in the home approximately every other month, the children were given experimenter-designed tests periodically, and mothers were asked to keep diaries of their children's lexical development. The children were given standardized tests as they exited the study. Cognitive development was also measured periodically. The patterns of lexical and cognitive development of the prematures did not differ markedly from those of full-term infants. There were no significant differences between the prematures as a whole and the full-term infants on standard language test measures as they exited from the study. There were significant differences between the very low birthweight and full-term infants on two of the exit measures. However, the performance of the very low birthweight infants was well within the range of normal on these two measures. The nature of the study and the factors that might have led to lack of differences between the two groups are discussed.

Cognition↗
PubMed1991

Parvovirus B19 infection of the fetus. Histology and in situ hybridization.

Fetal tissues from 16 spontaneous abortions, two terminations, and one perinatal death, 18 of which were associated with maternal human parvovirus B19 infection, were examined for B19 infection by histology and in situ hybridization using a digoxigenin-labeled B19-DNA probe. In 15 spontaneous abortions and one termination, erythroblasts with intranuclear inclusions (lantern cells) reacted with B19-DNA by in situ hybridization. No internal or external fetal malformations were observed. Because 13 (86.7%) spontaneous abortions with lantern cells occurred between the 20th and 28th weeks of gestation, it is postulated that B19 infection may be a particular threat to the fetus during this stage of gestation.

Adult↗