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Biomedical subjects

L Wood

Publications and source records attributed to L Wood.

At least 163 records · Page 9Linked to original sources
PubMed1988

Head-to-head arrangement of murine type IV collagen genes.

The genes for the two dissimilar subunits of type IV collagen are organized in a head-to-head manner with their translation initiation codons within 874 base pairs. Murine genomic clones which contain portions of both genes have been isolated and characterized. These clones contain the first exon of the alpha 1(IV) chain and the first 3 exons for the alpha 2(IV) chain within a 1.7-kilobase HindIII fragment. The intergenic region appears not to resemble previously described bidirectional promoters. The HindIII fragment is present as a single copy in the mouse genome ruling out the presence of one of these gene fragments as a pseudogene. These findings agree with linkage studies of these two genes and differ from the known organization of human fibrillar collagen genes which have been found to be dispersed within the human genome.

Amino Acid Sequence↗
PubMed1988

Isolation of a new human herpesvirus producing a lytic infection of helper (CD4) T-lymphocytes in peripheral blood lymphocyte cultures--another cause of acquired immunodeficiency?

A new human helper (CD4) T-lymphotropic herpesvirus (HTLHV) was first isolated in February 1985 from the cultured peripheral blood lymphocytes (PBL) of a patient with the acquired immunodeficiency syndrome, and subsequently from the PBL of 1 patient with hairy cell leukaemia and 2 patients with lymphoproliferative disease associated with human T-lymphotropic virus type I infection. The viruses could be serially subcultured in umbilical cord PBL cultures in which they infected helper (CD4) T-lymphocytes producing multinucleate giant cells with intranuclear inclusions followed by cell lysis. Electron microscopy of infected cultures revealed that the isolates were herpesviruses. Specific DNA probing showed that the 4 isolates were related to one another but were distinct from cytomegalovirus, Epstein-Barr virus, Herpesvirus hominis types 1 and 2, and varicella-zoster virus. HTLHV lyses the same target cell as human immunodeficiency virus in PBL cultures suggesting that it may have a similar potential to cause acquired immune deficiency. The development of an unequivocally diagnostic serological test is a priority, so that the epidemiology and pathogenesis of HTLHV infection can be studied.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Responses of quadriceps motor units to mechanical stimulation of knee joint receptors in the decerebrate cat.

Recordings were obtained from single quadriceps motor units in decerebrate cats. Tonic discharges were induced in these units by stretch applied to the patellar tendon. The activity of these motor units was examined during repetitive mechanical indentation of the posterior aspect of the knee joint capsule. The amplitude of indentation could be graded to regularly elicit a volley of one or more action potentials from afferents travelling in the posterior articular nerve (PAN). Either repetitive indentation at a fixed frequency or random indentation resulted in entrainment of motor unit discharge with a latency of 6.5-17 ms from the onset of the first PAN spike. This effect was achieved in one case by a single joint afferent. Usually two or more afferents were required to produce entrainment. This effect was mediated by joint receptors as its reversibly abolished by application of lignocaine to the joint nerve. The modal reflex latency suggests that group II joint afferents were responsible for this effect. Stimulation of some areas of the joint capsule readily produced motor unit entrainment whereas other areas did not although PAN afferents were also activated at the latter sites, suggesting inhomogeneity in the synaptic actions of joint afferents.

Action Potentials↗
PubMed1988

Classical swine fever: virulence and tissue distribution of a 1986 English isolate in pigs.

Following the recurrence of classical swine fever in the United Kingdom in 1986, a virus isolated from a single outbreak was studied. A major factor in the spread of this disease is considered to be the presence of infectious virus in tissues taken from animals at certain stages of infection, although their condition may escape detection by routine inspection either before or after slaughter. Intranasal inoculation of the isolate into eight-week-old pigs reproduced the acute form of the disease. The pigs were killed or died between seven and 25 days after inoculation. The virus concentration was determined in a wide range of tissues taken at different stages of infection. Infectious virus was present at high concentrations in all the tissues taken and at all stages of infection. Any porcine tissue is therefore a potential source of infection even when it is taken either before the animal displays detectable signs of disease of after it develops serum neutralising antibodies.

Animals↗
PubMed1988

A genetic, pathological and virological study of congenital hypotrichosis and incisor anodontia in cattle.

Two Friesian cows, half-sibs by a common dam, produced four bull calves with severe congenital hypotrichosis and incisor anodontia and three normal heifers by six unrelated Holstein, Friesian, Devon and Hereford bulls. The two dams, and their dam, had coats of a short, stubbly nature and the pigmented areas appeared rusty grey rather than black. Pathological examination of skin samples taken from multiple standardised sites from two of the affected calves showed a reduction in the number of large first-formed hair follicles. Smaller calibre hair follicles were present but, unlike those of normal neonatal calves, all were in the telogen (inactive) phase. Although the herd was infected with bovine virus diarrhoea virus there was no convincing evidence that the virus was implicated in the pathogenesis of these cases of congenital hypotrichosis with incisor anodontia. The family breeding information on the few severely affected and normal progeny and mildly affected and normal parents may be explained by the genetic hypothesis of an X-linked incompletely dominant gene.

Alopecia↗
PubMed1988

cDNA clones completing the nucleotide and derived amino acid sequence of the alpha 1 chain of basement membrane (type IV) collagen from mouse.

Six cDNA clones add 3549 nucleotides to the DNA sequence of the alpha 1 chain of basement membrane (type IV) collagen. Thus the complete nucleotide and derived amino acid sequence of the alpha 1 type IV collagen with 5007 nucleotides coding for 1669 amino acids with a calculated Mr of 160,827 is known. The six cDNA clones cover the putative N-terminal signal peptide, the 7 S region and two thirds of the helical region extending into the previously published murine nucleotide sequence [(1986) Gene 43, 301]. The protein sequence for 289 amino acids of the helical region adjacent to the 7 S region has not previously been published for any species.

Amino Acid Sequence↗
PubMed1988

Positive correlation of corneal thickness and endothelial cell loss. Serial measurements after cataract surgery.

A significant linear correlation was found between increase in corneal thickness (delta CT) in the immediate postoperative period and percentage of cell loss one and six months after surgery in a prospective study on cataract surgery. Eyes were grouped according to delta CT, and the groups were compared according to the percentage of cell loss. Eyes with delta CT of 0.1 mm or more at five days lost significantly more cells at one and six months than eyes with delta CT of less than 0.025 mm. Eyes were then regrouped according to the percentage of cell loss. Those with cell loss of 30% or more were found to have significantly greater delta CT at 48 hours and five days than eyes with cell loss of less than 30%. The derived probability of cell loss of 30% or more increases the greater the value of delta CT. For delta CT of 100 micron or more at five days, the probability of high cell loss is 30%; this is nearly three times the likelihood that high cell loss had occurred when delta CT is less than 100 micron. Our results suggest that delta CT could be a useful clinical indicator of endothelial cell loss.

Cataract Extraction↗
PubMed1988

cDNA clones coding for the complete murine B chain of complement C1q: nucleotide and derived amino acid sequences.

We have isolated cDNA clones covering the complete B chain of the complement subunit C1q from mouse; this subunit initiates the classical complement pathway. Deoxynucleotide sequence analysis shows that these clones contain 156 nucleotides of the 5' untranslated region, followed by sequences coding for the 25 amino acids of the signal peptide, all of the 228 amino acids of the mature protein and 140 nucleotides of the 3' untranslated region, including a poly A addition signal. The coding region for the mature protein contains 261 nucleotides for the Gly-X-Y repeat and 408 nucleotides for the globular portion of C1q. By comparing the nucleotide sequence of the mouse B chain of C1q with the B chain from human (Reid, K. B. M., 1985, Biochem. J. 231, 729), we find a high homology (80%) within the mature protein, a lower homology within the signal peptide (59%) and the 3' untranslated region (47%) and no homology (26%) in the 5' untranslated region.

Amino Acid Sequence↗
PubMed1988

cDNA clones coding for the complete murine B chain of complement Clq: nucleotide and derived amino acid sequences.

We have isolated cDNA clones covering the complete B chain of the complement subunit Clq from mouse; this subunit initiates the classical complement pathway. Deoxynucleotide sequence analysis shows that these clones contain 156 nucleotides of the 5' untranslated region, followed by sequences coding for the 25 amino acids of the signal peptide; all of the 228 amino acids of the mature protein; and 140 nucleotides of the 3' untranslated region, including a poly A additional signal. The coding region for the mature protein contains 261 nucleotides for the Gly-X-Y repeat and 408 nucleotides for the globular portion of Clq. By comparing the nucleotide sequence of the mouse B chain of Clq with the human B chain (Reid, K.B.M., 1985, Biochem. J. 231, 729), we find a high homology (80%) within the mature protein, a lower homology within the signal peptide (59%) and the 3' untranslated region (47%) and no homology (26%) in the 5' untranslated region.

Amino Acid Sequence↗
PubMed1988

Pure red cell aplasia. Stable complete remission following antilymphocyte globulin administration.

A 25-yr-old woman with idiopathic pure red cell aplasia achieved complete remission following a single 5-day course of antilymphocyte globulin at a dose of 50 mg/kg daily by intravenous injection as initial and sole therapy. Apart from transient arthralgia and asymptomatic thrombocytopenia there were no side effects. At 2 yr, the patient has normal peripheral blood, bone marrow and in vitro culture studies. This approach offers an alternative to conventional immunosuppressive therapy where there is evidence of an underlying immune disorder.

Adult↗
PubMed1988

The effect of acute joint inflammation on flexion reflex excitability in the decerebrate, low-spinal cat.

Experiments were performed to investigate whether acute knee joint inflammation, induced by intra-articular injection of carrageenan and kaolin, significantly influences the magnitude of the flexion withdrawal reflex of knee flexors in the decerebrate, low-spinal cat. It was observed that after injection of these inflammatory agents, reflex intensity increased with a time course that matched the development of the inflammatory process, as assessed by monitoring the intra-articular temperature. Control experiments involving intra-articular injection of saline showed neither a rise in intra-articular temperature, nor any change in reflex intensity. The normal pattern of modulation of reflex intensity with changing joint angle was abolished in the inflamed joint with the reflex being equally intense at all positions tested. Abolition of neural activity in the inflamed joint by intra-articular injection of lignocaine resulted in a marked decrease in the reflex back to control values, suggesting that there is no maintained increase in central excitability in the absence of joint afferent input. It was also observed that the spontaneous activity of knee flexor motor units was modulated during continuous passive rotation of the knee, with activity being greater in extension than in flexion. This pattern reversed when the knee was acutely inflamed, but could be returned to the control pattern by joint anaesthesia, although now the response was attenuated when compared to the control.

Animals↗
PubMed1988

Pressures in normal and acutely distended human knee joints and effects on quadriceps maximal voluntary contractions.

Pressures were recorded in ten knees from five subjects with informed consent. Resting intra-articular pressures were found to be sub-atmospheric with a mean value of -5 +/- 1.5 mmHg (S.E. of mean). There was little variation in intra-articular pressure with changing joint angle in the normal joint. Infusion of as small a volume as 5 ml of sterile saline into the joint cavity caused the intra-articular pressure to increase to supra-atmospheric levels. Changing joint angle now produced clear modulations in intra-articular pressure. Pressure increased as the limb was moved out to extension and back to flexion with a minimum occurring in the mid-range. These modulations were more pronounced with active positioning of the joint than with passive positioning. Successive increases in intra-articular volume produced increases in intra-articular pressure as well as the degree of modulation of intra-articular pressure with joint angle. Cyclical flexion-extension movements caused a progressive decrease in the maximum pressure observed in extension. Non-noxious distension of the knee joint caused substantial reductions in the magnitude of isometric and isokinetic maximal voluntary contractions of quadriceps due to a reflex inhibition from joint mechanoreceptor afferents.

Electromyography↗
PubMed1987

The effect of mechanical stimulation of knee joint afferents on quadriceps motor unit activity in the decerebrate cat.

The present experiments demonstrate that repetitive activation of as few as two joint afferents by an imposed mechanical stimulus results in entrainment of stretch-induced firing of quadriceps motor units. There is no significant input from extracapsular receptors as the effect is abolished during local anaesthetic block of the joint nerve. These results indicate that joint receptors can exert potent effects on motoneurone excitability which may be of considerable functional significance.

Animals↗
PubMed1987

Risk of unexplained stillbirth at different gestational ages.

In 40,635 deliveries in 1978-85, unexplained stillbirths were an important component (nearly a quarter) of all perinatal deaths. The rate of unexplained stillbirth (unexplained stillbirths divided by total births) was highest among preterm deliveries, fell to a minimum at 39-40 weeks' gestation, then rose at 41-42 weeks. Rate is generally accepted as measuring risk, but since it is the population of undelivered, not delivered, infants that is at risk of intrauterine death, stillbirth risk would be better measured as the number of impending stillbirths divided by the total number of undelivered fetuses. With this measure the risk of unexplained stillbirth was least in preterm pregnancies, rising fourfold after 39 weeks to a maximum at 41 weeks. At this time, it was also four times higher than at 33 weeks, in contrast to the rate, which was nineteen times lower.

England↗