Matrix methods for solving protein substructures of chlorine and sulfur from anomalous data.

The weak signal obtained from the anomalous scattering (at lambda = 1.54 A) of naturally occurring elements such as sulfur, phosphorus and ordered solvent chloride ions is used to determine the atomic positions of these atoms. Two examples are discussed: the sulfur and chlorine substructure of tetragonal hen egg-white lysozyme and an oligonucleotide containing ten P atoms. The substructure of lysozyme was also solved from Cu K(alpha) radiation data collected on a standard rotating-anode generator. The results presented here are an illustration of the power of the matrix methods, which are to be implemented in next distribution of the direct methods package CRUNCH.

Digestion of so-called resistant starch sources in the human small intestine.

BACKGROUND: Resistant starch sources, which are only partially digested in the small intestine, can be used to increase colonic availability of short-chain fatty acids. OBJECTIVE: To study the characteristics of the fermentation of resistant starch, the digestion of resistant starch in the small intestine has to be quantified. We compared the metabolic fates of highly digestible cornstarch (DCS), Hylon VII (type 2 resistant starch), and Novelose 330 (type 3 resistant starch), which are of corn origin and, therefore, naturally enriched in (13)C. DESIGN: After administration of 40 g starch or glucose to 7 healthy volunteers, glucose and exogenous glucose concentrations in serum and (13)CO(2) excretion in breath were analyzed for 6 h. (13)C abundance in carbon dioxide was analyzed by isotope ratio mass spectrometry (IRMS) and (13)C abundance in glucose by gas chromatography-combustion IRMS. RESULTS: By comparing the area under the curve (2 h) of exogenous glucose concentration in serum ((13)C glycemic index) after intake of starch or glucose, (13)C glycemic indexes for DCS, Hylon VII, and Novelose 330 were calculated to be 82 +/- 23%, 44 +/- 16%, and 43 +/- 15%, respectively. Comparison of 6-h cumulative percentage dose recovery in breath showed that 119 +/- 28% of DCS, 55 +/- 23% of Hylon VII, and 50 +/- 26% of Novelose 330 was digested in the small intestine. CONCLUSION: The exogenous glucose response in serum and the (13)CO(2) excretion in breath can be used to estimate small intestinal digestion of resistant starch, which amounts to approximately 50%.

[Tingling in the hands]. / Prikkelingen in de handen.

Four patients whose most prominent complaint was tingling in the hands are presented. In the first patient, a 33-year-old man, the cause appeared to be a traumatic cervical myelomalacia caused by a rear end collision three years before. The second patient, a 34-year-old woman, initially only had tingling in the hands but eventually developed paresis of the right arm and leg. MRI followed by surgery revealed a centrally located ependymoma. The third patient had a cervical disc protrusion to the left at CVI-CVII. This 49-year-old man recovered after rest and physical therapy. The last patient, a 23-year-old woman, had tingling in the ulnar area of the left hand. This appeared to be caused by an avulsion of the medial epicondyle of the humerus, the result of a trauma 10 years before. After extirpation of the epicondyle the complaints disappeared. In patients with paraesthesias it is very important to take the history meticulously and to perform thorough neurological examination. A simple neuroanatomical scheme may be used to interpret the somatosensory findings.

Chiral recognition between host and guest: a binaphthyl-18-crown-6 host with D-phenylglycinium methyl ester perchlorate guest. A difficult structure solved with CRUNCH.

The complex between (R)-4,5,7,8,10,11,13,14,16,17-decahydro-2,19- diphenyldinaphtho[2,1-q:1',2'-s][1,4,7,- 10,13,16]hexaoxa[2,5,8,11,14,17,19]cycloicosaheptene {Chemical Abstracts name: (R)-4,5,7,8,10,11,13,14,16,17-decahydro-2,19- diphenyldinaphtho[2,1-q:1',2'-s][1,4,7,-10,13,16]hexaoxacycloic osin} and D-2-phenylglycinium methyl ester perchlorate, C9H12NO2+.ClO4-.C42H40O6.-H2O, crystallizes in the orthorhombic space group P2(1)2(1)2(1) with two C9H12NO2+.C42H40O6 complexes, two ClO4- ions and two molecules of water in the asymmetric unit. Crystal data: M(r) = 924.44, a = 23.048 (7), b = 34.383 (6), c = 11.992 (6) A, V = 9503 (6) A3, Z = 8, Dx = 1.292 Mg m-3, F(000) = 3904, mu(Cu K alpha) = 1.261 mm-1, T = 175 K, R = 0.0896 for all 7784 reflections, 1208 parameters refined in three blocks with 29 restraints. Nearly twenty years elapsed between the first data collection and the solution of the structure with the direct-methods program CRUNCH. The structural details are of interest because enantiomers of this host show a high degree of discrimination between enantiomers of alpha-amino acids and their esters. The crystal structure demonstrates the influence of C-H...O and C-H...pi interactions on the unexpected orientation of the guest in the host cavity. The same orientation is found in both of the unique complexes, and the geometric details are in agreement with solution studies.

Successful conservative treatment of rheumatoid subaxial subluxation resulting in improvement of myelopathy, reduction of subluxation, and stabilisation of the cervical spine. A report of two cases.

OBJECTIVE: To report the efficacy of conservative treatment with cervical traction and immobilisation with a Halo vest, in two consecutive rheumatoid arthritis patients with progressive cervical myelopathy caused by subaxial subluxation. METHODS: Description of neurological symptoms and signs and findings in plain radiography (PR) and magnetic resonance imaging (MRI) of the cervical spine before and after treatment of the subaxial subluxation by traction and immobilisation with a Halo vest during four months. RESULTS: During four months of traction and immobilisation neurological examination showed a considerable improvement of the signs and symptoms of cervical myelopathy. Afterwards PR and MRI of the cervical spine showed reduction of the subaxial subluxation. Eventually firm stabilisation was obtained in both patients without surgery of the cervical spine. CONCLUSION: Cervical traction and immobilisation with a Halo vest can be considered as an independent conservative treatment in rheumatoid arthritis patients with cervical myelopathy caused by subaxial subluxation.

[Two patients with osteochondroma of the cervical spine]. / Twee patiënten met een osteochondroom van de cervicale wervelkolom.

In two patients, both women of 32 years old, who had a local tumour in the neck firmly attached to the spine, radiologic imaging and biopsy led to the diagnosis of osteochondroma. Both patients recovered, but one had an episode of atrophy of the M. trapezius and the M. rhomboideus. If a solid mass is palpated in the neck a malignant process and cervical exostosis should be considered in the differential diagnosis. Exostoses usually are benign symptomless tumours, diagnosed in the second or third decade of life. They may compress spinal nerves and in rare cases cause severe complications by compression of vital structures such as myelum and arteries. An exostosis should be resected only if it is symptomatic or if a malignant process is suspected. In case of doubt surgical intervention is indicated with special attention to surrounding structures such as nerves and blood vessels.

New developments in phase refinement.

A longstanding problem in X-ray crystallography is that vital information regarding the crystal phases in missing from the experimental data that are gathered in the diffraction experiment. Prior knowledge needs to be introduced in order to resolve phase ambiguities whenever the diffraction data are not sufficient to unequivocally reconstruct the crystal phases through anomalous or isomorphous differences. Very recent developments include progress in the application of direct methods to small proteins and other compounds of a similar small size (Shake 'n' Bake, SHELXD, CRUNCH and SIR96), bias-free refinement through the gamma-correction (Solomon), improvements in the determination of phase probability distributions (SHARP) and automated atomic refinement (wARP).

Von Recklinghausen neurofibromatosis (VRNF) and pregnancy. A single case study.

A case of Von Recklinghausen neurofibromatosis (VRNF) with progression during two pregnancies and obstetrical complications is described to illustrate the effect of pregnancy on VRNF and vice versa. The interaction between VRNF and pregnancy is discussed. The obstetrical complications and progression of VRNF lesions during pregnancy necessitate close follow-up of these patients by neurologist and obstetrician.

The conservative treatment of patients presenting with Grisel's syndrome.

Two cases of Grisel's syndrome are described to demonstrate that early recognition of this condition allows effective conservative treatment. To explain the good response to early conservative treatment, a combination of hypotheses is proposed.

Sciatic nerve compression by an aneurysm of the internal iliac artery.

A 73-year-old female with severe sciatica suffered from an aneurysm of the left internal iliac artery. At first minimal caudographic abnormalities suggested intervertebral disc herniation and lumbar root compression but at exploratory surgery the diagnosis had to be rejected. Once the correct diagnosis was established by echography, CT-scanning and angiography surgical treatment of the aneurysm resulted in complete recovery. Because sciatic nerve lesions due to aneurysms in the pelvic region very seldom occur and may be the cause of diagnostic confusion, symptoms and treatment of these aneurysms are discussed.

Lumbosacral lipoma investigated by conventional radiography, ultrasound and direct coronal mode CT-scanning.

The authors describe a case of lipoma of the lumbosacral region, associated with meningocele in an infant and advocate the utilization of CT scanning in direct coronal mode (DCM) and ultrasound (US) as means of diagnosis of the extension and geography of the lesion and differential diagnosis. The surgical management is also indicated.

Congenital block vertebrae C2-C3 in patients with cervical myelopathy.

One hundred and forty-five patients presenting with symptoms of cervical myelopathy were treated surgically. Eight of these patients (5.5%) showed congenital block vertebrae C2-C3. The relationship between this congenital anomaly and the occurrence of spondylotic myelo-radiculopathy is discussed.