Substance P and cholecystokinin-like immunoreactive varicosities in somatosensory and autonomic regions of the rat spinal cord: a quantitative study of coexistence

Substance P- and cholecystokinin-like immunoreactivities have been shown to coexist in some, but not all, dorsal root ganglion cell bodies of the rat. Quantitative immunofluorescence techniques were used in the present study to describe densities of substance P- and cholecystokinin-like immunoreactive varicosities in several spinal cord nuclei. By combining simultaneous immunofluorescent techniques on one tissue section with computerized image processing, coexistence of substance P- and cholecystokinin-like immunoreactivity in varicosities was also quantified. By comparing spinal cord regions between normal and unilateral dorsal rhizotomy affected animals, densities of substance P- and cholecystokinin-like immunoreactive varicosities associated with primary afferent neurons were established. To determine the densities of immunoreactive varicosities that were related to unmyelinated primary afferent fibers, data were compared between normal animals and those treated neonatally with capsaicin. Four major observations were made: (1) Substance P- and cholecystokinin-like immunoreactivity coexist in populations of varicosities in sensory and autonomic regions of rat spinal segment L6. (2) Within the superficial laminae of the dorsal horn, varicosities containing both substance P- and cholecystokinin-like immunoreactivity and cholecystokinin-like immunoreactivity alone are of primary afferent neuron origin, but those containing only substance P-like immunoreactivity are most likely of spinal or descending neuronal origin. (3) Capsaicin-insensitive cholecystokinin-like immunoreactive varicosities were present predominantly in lamina I. These data suggest some cholecystokinin-like immunoreactive varicosities are associated with myelinated primary afferent neurons. (4) Primary afferent fibers containing substance P- and cholecystokinin-like immunoreactivity project to intermediate gray regions of the rat spinal cord. A large proportion of these fibers are capsaicin sensitive, suggesting that they are unmyelinated.     

Reproducibility of walking test results in chronic obstructive airways disease.

Thirty six patients with chronic airflow obstruction were studied to examine (1) the reproducibility and order effect of repeated walking tests when performed over consecutive days or consecutive weeks; (2) the correlation between walking distance and spirometric measurements; and (3) the effect of static visual clues on performance. In study 1, where 12 patients performed 12 walks over three consecutive days, five minute walking distance increased by 33% between walks 1 and 12, half of the increase occurring after the first three walks. In study 2, where 24 patients performed 12 walks over four consecutive weeks, five minute walking distance increased by 8.5% between walks 1 and 12. A learning effect was seen over the first nine walks. Static visual clues to performance did not affect the distance walked. Spirometric measurements showed no order effect in either study. Although walking distance correlated significantly with FEV1, forced vital capacity, and peak expiratory flow, these measurements were poor predictors of exercise performance. The learning effects seen on repeated performance of walking tests over short intervals should be considered when an individual's response to treatment is being interpreted. When walking tests are used in clinical trials a placebo group or randomised crossover design is essential.     

Human herpesvirus 6 (HHV-6) isolation from bone marrow: HHV-6- associated bone marrow suppression in bone marrow transplant patients [see comments]

These studies tested the hypothesis that human herpesvirus 6 (HHV-6) can cause posttransplant bone marrow (BM) suppression in BM transplant (BMT) patients. Fifteen adult patients who received T-lymphocyte- depleted, allogeneic BM transplants and who developed posttransplant BM suppression were studied. Detailed chart reviews were used to divide the patients into two groups: (1) those with diagnosed BM suppression (DBMS) and (2) those with idiopathic BM suppression (IBMS). BM aspirates obtained from the patients at the onset of BM suppression were subjected to an HHV-6 isolation procedure using mitogen-stimulated blood mononuclear cells. BM specimens obtained from another population of BMT patients solely to document engraftment irrespective of their BM function were also subjected to the HHV-6 isolation procedure as controls. HHV-6 was isolated from 6 of 15 BM samples from BMT patients with BM suppression. BM samples from patients with IBMS were more likely to be positive for HHV-6 than those from patients with DBMS (P < .01). Also, HHV-6-positive BM were significantly more likely (P < .05) to come from patients with suppression of more than one BM lineage than HHV-6-negative BM. Finally, samples of BM from an unselected series of BMT patients studied without regard to their BM function were less likely (P < .01) to be positive for HHV-6 than patients with IBMS.     

Characterization of a new TEM-derived beta-lactamase produced in a Serratia marcescens strain.

A natural TEM variant beta-lactamase was isolated from an epidemic strain of Serratia marcescens. Nucleotide gene sequencing revealed multiple point mutations located in the 42-to-44 tripeptide and positions 145 to 146, 178, and 238. In addition, a glutamic acid 212 deletion was also found. The purified enzyme was studied from a kinetic point of view, revealing the highest catalytic efficiency (k[cat]/Km) values for ceftazidime and aztreonam compared with the TEM-1 prototype enzyme. The in vitro resistance correlated with kinetic parameters, and the enzyme also mediated resistance to some penicillins and an ampicillin-clavulanic acid combination. The mutational and kinetic changes are discussed in relation to the three-dimensional crystallographic structure of the wild-type TEM-1 enzyme.     

Comparative studies on the effect of growth conditions on adhesion, hydrophobicity, and extracellular protein profile of Streptococcus sanguis G9B.

Streptococcus sanguis G9B was grown in continuous culture at different generation times and pH values in media containing either glucose or fructose and differing in the concentrations of Na+ and K+. The growth pH, carbohydrate, and cation concentration each affected the yield of organisms, their ability to adhere to saliva-coated hydroxyapatite beads, and their hydrophobicity, as measured by adhesion to hexadecane. There was no correlation between adhesion to saliva-coated hydroxyapatite beads and hydrophobicity, the values for hydrophobicity varying between 44 and 83% for organisms that adhered poorly and between 24 and 75% for those that adhered effectively. For organisms grown in batch culture at pH 6.0 or 7.0 there was similarly no correlation between adhesion and hydrophobicity. The growth conditions also had a considerable influence on the production of extracellular protein. The total amount was greater at pH 7.5 than at other pH values, and there were also differences in the individual components in response to changes in generation time, pH, carbohydrate source, and cation concentration. Two protein bands were identified, namely, glucosyltransferase and protein P1 (also called antigen B or I/II). However, there was no correlation between a particular protein component and adhesion.     

Malignant fibrous histiocytomas of salivary glands

The light microscopic, immunohistological and ultrastructural findings in two cases of malignant fibrous histiocytoma arising in salivary glands are presented and the features of seven previously reported cases are reviewed. This neoplasm is extremely rare in this site and may pose problems in diagnosis. It has to be distinguished from other spindled cell tumours, in particular from epithelial tumours of predominantly spindled cell pattern; immunohistological markers for histiocytic cells may be of value. The histogenesis of this neoplasm is controversial but our electron microscopic findings support an origin from mesenchymal cells which differentiate along a broad fibrohistiocytic spectrum.