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Biomedical subjects

H Evans

Publications and source records attributed to H Evans.

At least 55 records · Page 3Linked to original sources
PubMed1995

Metabolic epidermal necrosis in two dogs with different underlying diseases.

Two dogs with metabolic epidermal necrosis had hyperkeratosis of the footpads accompanied by erythematous, erosive and crusting lesions affecting the muzzle, external genitalia, perineum and periocular regions. Histopathological examination of skin biopsies revealed a superficial hydropic dermatitis with marked parakeratosis. Both dogs had high plasma activities of alkaline phosphatase and alanine aminotransferase and high concentrations of glucose, and also a marked hypoaminoacidaemia. Despite these similarities, the cutaneous eruptions were associated with different underlying diseases. One dog had a pancreatic carcinoma which had metastasised widely; the primary tumour and the metastases showed glucagon immunoreactivity on immunocytochemical staining, and the dog's plasma glucagon concentration was markedly greater than that of control dogs. The other dog had diffuse hepatic disease; its plasma glucagon concentration was similar to that of control samples and cirrhosis was identified post mortem. Metabolic epidermal necrosis in dogs is a distinct cutaneous reaction pattern which may be associated with different underlying systemic diseases; however, the pathogenesis of the skin lesions remains unclear.

Alanine Transaminase↗
PubMed1995

Calcium absorption, endogenous excretion, and endocrine changes during and after long-term bed rest.

Negative calcium balance is a known consequence of bed rest, and is manifested in elevated urine and fecal calcium (Ca). Elevated fecal Ca can result from either decreased absorption, increased endogenous fecal excretion, or both. We measured the Ca absorption and endogenous fecal excretion in eight healthy male volunteers before and during 4 months of bed rest. Dual isotope (n = 6) or single isotope (n = 2) methods in conjunction with Ca balance were used to calculate true and net Ca absorption and endogenous fecal excretion. Stool Ca increased from 797 mg/day (mean intake 991 mg/day) to 911 mg/day during bed rest, whereas urine Ca excretion increased from 174 to 241 mg/day. True Ca absorption decreased from 31 +/- 7% of Ca intake pre-bed rest to 24 +/- 2% during bed rest, (p < 0.05) and returned toward pre-bed rest values within 5-6 weeks following reambulation. Endogenous fecal excretion did not change significantly, and therefore, most of the increased fecal Ca resulted from changes in absorption. However, in one individual, endogenous fecal Ca excretion was the major contributor to Ca loss. Ionized Ca and pyridinium crosslinks increased and 1,25(OH)2 vitamin D decreased during bed rest, similar to the decrease in Ca absorption; parathyroid hormone (PTH), calcitonin, serum albumin, phosphorus, and total serum Ca were unchanged. Although alkaline phosphatase, osteocalcin, and PTH were unchanged during bed rest, they were elevated during reambulation. These changes accompanied by increased Ca absorption and balance and decreased ionized and total serum Ca suggest a rebound in bone formation following immobilization.

Absorption↗
PubMed1995

Assessment of dose and time responses to TRH and thyrotropin in healthy dogs.

Changes in total thyroxine (T4 [TT4]), free T4 (FT4) and total tri-iodothyronine (T3 [TT3]) in serum after the intravenous administration of different doses of thyrotropin (TSH) and thyrotropin-releasing hormone (TRH) were measured in six healthy beagles. Significant (P < 0.05) elevations in serum TT4, FT4 and TT3 were observed at each sampling time (two, four, five, six, seven, eight and 10 hours) after administration of 1, 3 or 5 iu (total dose) TSH and peak mean responses were observed six to eight hours after injection. At six hours after injection the mean TT4, FT4 and TT3 levels were approximately 2.6, 3.9, and 1.5 times basal levels, respectively, and there were no significant differences between the three doses of TSH, Significant (P < 0.05) elevations in serum TT4 and FT4 but not TT3 were observed at each sampling time (two, four, five, six, seven and eight hours) after the administration of TRH. Peak mean responses were observed at four hours after injection at which time TT4 and FT4 levels were approximately 1.7 and 1.9 times basal levels, respectively. No significant differences were observed between the four doses of TRH used (100, 200, 300, and 600 micrograms total dose). Concentrations of TT4, FT4 and TT3 were significantly (P < 0.05) higher following the administration of TSH compared with TRH, and the response to TRH showed greater individual variation.

Analysis of Variance↗
PubMed1995

Regional muscle loss after short duration spaceflight.

BACKGROUND: Muscle strength and limb girth measurements during Skylab and Apollo missions suggested that loss of muscle mass may occur as a result of spaceflight. Extended duration spaceflight is important for the economical and practical use of space. The loss of muscle mass during spaceflight is a medical concern for long duration flights to the planets or extended stays aboard space stations. Understanding the extent and temporal relationships of muscle loss is important for the development of effective spaceflight countermeasures. HYPOTHESIS: We hypothesized that significant and measurable changes in muscle volume would occur in Shuttle crewmembers following 8 d of weightlessness. METHODS: MRI was used to obtain the muscle volumes of the calf, thigh and lower back before and after the STS-47 Shuttle mission. RESULTS: Statistical analyses demonstrated that the soleus-gastrocnemius (-6.3%), anterior calf (-3.9%), hamstrings (-8.3%), quadriceps (-6.0%) and intrinsic back (-10.3%) muscles were decreased, p < 0.05, compared to baseline, 24 h after landing. At 2 weeks post recovery, the hamstrings and intrinsic lower back muscles were still below baseline, p < 0.05. CONCLUSIONS: These results demonstrate that even short duration spaceflight can result in significant muscle atrophy.

Adult↗
PubMed1994

Innervation of the spondylolysis "ligament".

SUMMARY OF BACKGROUND DATA: Spondylolysis of the lower lumbar vertebrae is a non-united childhood fracture of the arch of the vertebra, persisting into adult life. Symptoms of disabling low back pain appear in a minority of patients, usually for the first time in adulthood. This pain is considered to arise from several separate sources, one of which may be the spondylolysis ligament. STUDY DESIGN: The innervation of the ligament has been investigated immunohistochemically. METHODS: Specimens from eight patients were divided longitudinally for histology including hematoxylin and eosin, toluidine blue, and elastic van Gieson. Histochemistry involved immunostaining for the neuropeptides: protein gene product, calcitonin gene related peptide, substance P, vasoactive intestinal peptide, and the c-flanking peptide of neuropeptide Y. RESULTS: Immunoreactivity to calcitonin gene-related peptide, the c-peptide of neuropeptide Y, and vasoactive intestinal peptide was identified in the ligament or in the adjacent adipose tissue. CONCLUSION: The movement that the ligament allows at the fracture site may result in stimulation of the nerve endings both in the ligament and in the surrounding soft tissue.

Adult↗
PubMed1994

Pulmonary carcinoid with papillary structure: report of a case with fine-needle aspiration cytology.

Fine-needle aspiration biopsy of a peripheral lung mass in a 44-yr-old man revealed a papillary tumor. Histologic examination of the mass, removed by lobectomy, demonstrated a pulmonary carcinoid tumor with papillary structure. Most papillary tumors of the lung are malignant. Pulmonary carcinoid and pulmonary sclerosing hemangioma--benign tumors--have papillary variants. Both have been described in fine-needle aspiration specimens and should be included in the differential diagnosis of papillary lung tumors. The cytologic features of pulmonary carcinoid are described.

Adult↗
PubMed1994

Proteoglycan components of the intervertebral disc and cartilage endplate: an immunolocalization study of animal and human tissues.

Monoclonal antibodies have been used to study the presence and distribution of various components of the proteoglycan molecule in the intervertebral disc and cartilage endplate. Link protein, hyaluronic acid binding region, keratan sulphate and chondroitin 4- and 6-sulphate have been investigated in tissues from humans and other mammals. Exposure of the carbohydrate and protein epitopes was enhanced by chondroitinase and trypsin pretreatment respectively. The degree of immunoreactivity varied with location, being greater in the nucleus pulposus than the annulus fibrosus with least reactivity in the cartilage endplate. In addition, there was increased staining in the pericellular domains, particularly in adult tissues. Areas of ectopic calcification exhibited very different immunoreactivity, depending on the type of calcium salt present. Calcium hydroxyapatite deposits showed greater staining for 8A4 (link protein), while calcium pyrophosphate deposits demonstrated greater staining for 3B3(-), 7D4(-) and 3D5 than the surrounding non-calcified matrix. Staining for chondroitin sulphate isomer epitopes 3B3(-) and 7D4(-), indicative of modified chondroitin sulphate chains, was greater in human tissues of degenerate than non-degenerate appearance. This suggests that expression of these epitopes may be an indicator of disease and subsequent reparative procedures in intervertebral disc and cartilage endplate, similar to that seen in articular cartilage degeneration.

Adolescent↗
PubMed1994

Pharyngeal pouch: link with reflux and oesophageal dysmotility.

Twenty patients aged 56-92 years who underwent surgical correction of pharyngeal pouches at Queen Alexandra Hospital, Portsmouth were asked to fill in a detailed questionnaire. They were then interviewed and barium swallow studies performed from 3 months to 4 years post-operatively. Nineteen patients in the sample were found to have reflux and 20 had dysmotility. These findings suggest that pharyngeal pouches are not a purely localized inco-ordination of the cricopharyngeal sphincter but are associated with a generalized oesophageal muscle dysfunction.

Aged↗
PubMed1994

Sensitivity of the fibrinogen clotting time: an in vitro test of potential thrombogenicity.

The fibrinogen clotting time (FCT) is a measure of thrombin activity, and is used to evaluate the potential thrombogenicity of prothrombin complex concentrates (PCC). We have defined end points for clot formation in this test which allow the measurement in PCC of thrombin concentrations as low as 0.001 IU/ml. The FCT of thrombin and PCC samples which did not contain antithrombin III (ATIII) were the same when measured at 20 degrees C or 37 degrees C. In the presence of ATIII (0.05 or 0.25 IU/ml), samples of PCC which were known to contain thrombin showed shorter FCT at 20 degrees C than at 37 degrees C. Inclusion of both ATIII (0.25 IU/ml) and heparin (4 IU/ml) in PCC ensured the complete inactivation of endogenous thrombin.

Antithrombin III↗
PubMed1994

Modulation of left ventricular relaxation in isolated ejecting heart by endogenous nitric oxide.

Nitric oxide (NO) modulates myocardial contractile behavior in several isolated preparations, e.g., cardiac myocytes and papillary muscles, via elevation of intracellular guanosine 3',5'-cyclic monophosphate (cGMP). We have recently reported that the exogenous NO donor, sodium nitroprusside, selectively modulates left ventricular (LV) relaxation in the isolated ejecting guinea pig heart, independent of coronary flow. We now report the effects of endogenously released NO on LV performance in this preparation (constant heart rate and loading). Both bradykinin (1 nM, n = 6) and substance P (100 nM, n = 6) accelerated early LV relaxation (maximum change in time constant, tE, -10.5 +/- 1.6 and -13.4 +/- 2.1%, respectively; both P < 0.05), without significantly altering early systolic parameters (e.g., rate of LV pressure development). These effects were inhibited by hemoglobin (P < 0.05; n > or = 6), which inactivates NO. Bradykinin (100 nM, n = 10) had an additional negative inotropic effect, which was not inhibited by hemoglobin. Neither agonist altered relaxation in isolated papillary muscles. These data suggest that endogenous NO, probably released from coronary microvascular endothelial cells, modulates LV relaxation in the intact heart.

Animals↗
PubMed1994

Rates of cesarean section and perinatal outcome. Perinatal mortality.

A comparison of relevant statistics from National Maternity Hospital, Dublin, Ireland and University Hospital, Newark, New Jersey, USA, for the years 1983-1989, revealed that after removal of major confounding factors, such as a fourfold difference in < 2500 gram births and an about tenfold discrepancy in the frequency of lethal congenital defects, the perinatal survival rates in all weight categories were significantly higher in the American center. The findings suggest that optimum perinatal results could not be achieved in an American high risk center with the approximately 6% abdominal delivery rate favored in Dublin. The same data also suggest, however, that the 17.5% rate of abdominal deliveries in Newark was unnecessarily high. The favorable impact of the relatively liberal use of cesarean section might have been derived in this study from a marked reduction of in utero losses, in the absence of an identifiable effect upon the rate of neonatal mortality.

Birth Weight↗
PubMed1993

Foodborne disease surveillance in England and Wales: 1989-1991.

This review summarises reports of food poisoning, salmonellosis, campylobacteriosis and other acute foodborne illness to the PHLS Communicable Disease Surveillance Centre, and notifications of food poisoning collated by the Office of Population Censuses and Surveys, in the period 1989-1991. During this period there were continuing rises in notifications of food poisoning and reports of salmonellosis and campylobacteriosis. There was considerable success in the control of foodborne listeriosis. Newly emerging pathogens, such as Vero cytotoxin producing Escherichia coli, became more important. There was unprecedented scrutiny of the salmonella data by experts and politicians, reflecting continuing concern over the role of eggs as well as poultry meat in the increase of Salmonella enteritidis phage type 4 infection. This concern, along with advances in information technology, has led to developments in the collection and dissemination of information which continue to be implemented.

Adolescent↗
PubMed1993

The efficacy of monohydroxamates as free radical scavenging agents compared with di- and trihydroxamates.

Desferrioxamine, the therapeutic iron chelator, is limited in its usage by its short half-life in plasma and lack of oral activity, its side-effects and its slow penetration into cells. Several studies have emerged recently demonstrating the ability of this trihydroxamate compound to act as a radical scavenger, in addition to and independently of its iron-chelating properties. These include the interaction of desferrioxamine with the superoxide radical and ferryl myoglobin radical, as well as its action as a chain-breaking antioxidant in peroxidizing erythrocyte membranes. We have synthesized recently a series of monohydroxamate compounds and investigated their efficacy as radical scavenging antioxidants in comparison with desferrioxamine and rhodotorulic acid, a naturally occurring dihydroxamate compound. The results show that the relative rates of reaction of these hydroxamate derivatives with ferryl myoglobin are N-methyl-N-hexanoyl hydroxylamine > N-methyl-N-benzoyl hydroxylamine > N-methyl-N-acetyl hydroxylamine > desferrioxamine > rhodotorulic acid > N-methyl-N-butyryl hydroxylamine.

Deferoxamine↗
PubMed1993

Cytology of Mollaret meningitis.

The diagnosis of Mollaret meningitis was established by cytologic examination of the cerebrospinal fluid (CSF) in a patient with recurrent aseptic meningitis. The characteristic features of the "Mollaret cell," an activated monocyte, are presented; theories of etiology are reviewed.

Aged↗
PubMed1993

Genomic organization and localization of the gene encoding human preprogalanin.

An approximately 35-kb region of genomic DNA encoding the human preprogalanin gene including 5' and 3' flanking sequences has been cloned and characterized. Exons and flanking introns were sequenced to determine the structural organization of the gene. The gene spans 6.5 kb, with the first exon encoding only the 5' untranslated sequence. The coding region of preprogalanin and the 3' untranslated sequence is divided into five exons. Using high-resolution fluorescence in situ hybridization, the position of the single human preprogalanin gene was localized to chromosome 11q13.3-q13.5. Several oncogenes have been mapped to this region, which is also the breakpoint for the translocation t(11;14)(q13;q32) in chronic lymphocytic leukemia and diffuse B-cell lymphoma.

Base Sequence↗
PubMed1993

Evaluation of muscle injury using magnetic resonance imaging.

The objective of this study was to investigate spin echo T2 relaxation time changes in thigh muscles after intense eccentric exercise in healthy men. Spin echo and calculated T2 relaxation time images of the thighs were obtained on several occasions after exercise of one limb; the contralateral limb served as control. Muscle damage was verified by elevated levels of serum creatine kinase (CK). Thirty percent of the time no exercise effect was discernible on the magnetic resonance (MR) images. In all positive MR images (70%) the semitendinosus muscle was positive, while the biceps femoris, short head, and gracilis muscles were also positive in 50% and 25% of the total cases, respectively. The peak T2 relaxation time and serum CK were correlated (r = 0.94, p<0.01); temporal changes in muscle T2 relaxation time and serum CK were similar, although T2 relaxation time remained positive after serum CK returned to background levels. We conclude that magnetic resonance imaging can serve as a useful tool in the evaluation of eccentric exercise muscle damage by providing a quantitative indicator of damage and its resolution as well as the specific areas and muscles.

Adult↗