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Biomedical subjects

P Roberts

Publications and source records attributed to P Roberts.

At least 19 recordsLinked to original sources
PubMed1992

Elevation of free beta subunit of human choriogonadotropin and core beta fragment of human choriogonadotropin in the serum and urine of patients with malignant pancreatic and biliary disease.

Human choriogonadotropin (hCG), its free beta subunit (beta hCG), and the core beta hCG fragment (c beta hCG) were measured by highly sensitive time-resolved immunofluorometric assays in the serum and urine of 29 patients with pancreatic cancer, 7 patients with biliary cancer, and 45 patients with benign pancreatic or biliary diseases. The results were compared with those of an age- and sex-matched reference population of nonpregnant women and men. Of the various forms of hCG assayed in serum, beta hCG showed the best diagnostic accuracy, and c beta hCG was the best marker in urine. Elevated serum concentrations of beta hCG were observed in 72% of the patients with pancreatic cancer, in 6 of 7 patients with biliary cancer, and in 9% of those with benign disorders. The serum concentrations of c beta hCG were elevated in 45%, 57%, and 2%, respectively, and those in urine in 55%, 71%, and 11%, respectively. The molar concentrations of c beta hCG in serum were mostly lower than those of beta hCG. Thus beta hCG secreted into serum appears to be the main source of c beta hCG in urine. Provided that they are measured by sufficiently sensitive and specific assays, beta hCG in serum and c beta hCG in urine appear to be useful markers for pancreatic and biliary cancer.

Adult↗
PubMed1992

Daily dose of ethanol and the development and decay of acute and chronic tolerance and physical dependence in rats.

Using behavioral and physiological measures, we compared the rates of development and decay of acute and chronic tolerance to ethanol (ET) and the severity of the withdrawal syndrome. Male rats were treated with 6, 9, or 12 g/kg/day ET or equicaloric dextrin maltose, delivered intragastrically. Although treatment duration varied, the total dose of ET was kept constant at 162 g/kg/rat for the three groups. The effects of a cumulative test dose of ET or equicaloric dextrin maltose, after exposure to a total of 0, 42, 83, 126, and 162 g/kg ET, and at 3, 5, and 7 days after termination of the chronic treatments, were evaluated on rectal temperature, dowel performance, and tail-flick and startle responses. After the initial five tolerance tests, chronic treatments were discontinued and rats were tested in a modified open-field apparatus and for their startle response to an auditory stimulus at 8, 12, 16, 20, 32, and 40 h later. With all measures, little tolerance developed in the 6-g/kg/day group. On the other hand, development of chronic tolerance was fastest in rats treated with the 12-g/kg/dose of ET. Chronic tolerance did not develop to ET's depressant effect on the startle response. Acute tolerance declined with chronicity of treatment in animals given the largest daily dose of ET. During withdrawal, and in contrast to the dextrin maltose-treated animals, there was impairment in all measures taken during the modified open-field test and hypersensitivity of the startle response for all three chronic ET-treated animals. Greatest behavioral impairment occurred in animals treated with 12 g/kg/day, and some impairment was still evident 40 h after the last dose of ET. Thus, the severity of the withdrawal syndrome was greatest in the group displaying the most acute and chronic tolerance.

Alcoholic Intoxication↗
PubMed1992

Reaction of skeletal muscle to small implants of titanium or stainless steel: a quantitative histological and autoradiographic study.

Small wire implants of titanium or stainless steel were inserted into mouse leg muscles to test the reaction of regenerating skeletal muscle. Muscle fibres regenerated rapidly, starting at 3 d; by 2 wk all implants were encapsulated in thin (10 microns) fibrous tissue capsule surrounded by myotubes for 15-20 microns. Quantitatively there were no detectable differences in muscle regeneration between the two metals. The initiation of myoblast precursor cell replication was determined in regenerating muscle next to the implants. Tritiated thymidine was injected 18-156 h after implant insertion and labelled myotube nuclei in the regenerated muscle indicated that their precursors had started DNA synthesis 24 h after implant insertion. This is similar to myogenesis in many other muscle lesions and indicated that neither titanium nor stainless steel retarded muscle regeneration.

Animals↗
PubMed1992

12q13 abnormality in rhabdomyosarcoma. A nonrandom occurrence?

We describe two cases of rhabdomyosarcoma with a translocation involving 12q13 as the primary cytogenetic abnormality. Literature review of 35 cases has identified 3 other cases with this abnormality, and we speculate that this may be another nonrandom rearrangement in rhabdomyosarcoma.

Adolescent↗
PubMed1992

Autosomal dominant 'Mediterranean fever' in a Finnish family.

A 23-year-old Finnish man was examined because of an 8-year history of recurrent bouts of fever and abdominal pain. His father had been repeatedly investigated because of similar episodes since he was 24 years old, and one of the father's sisters was reported to have had recurrent periods of fever. The clinical features closely resembled those of familial Mediterranean fever (FMF), a syndrome rarely described in families of European descent. Unlike typical FMF, which is inherited as an autosomal recessive trait, the mode of inheritance of the syndrome in our family may be regarded as dominant. During a recent attack, serum concentrations of interleukin-1-beta, interleukin-6 and acute phase reactants, including serum amyloid A protein, were high. No signs of amyloidosis were detected in our patients.

Adult↗
PubMed1992

Effect of immunization with Freund's adjuvant and pneumolysin on histologic features of pneumococcal infection in the rat lung in vivo.

Immunization with Freund's adjuvant and pneumolysin and stimulation with Freund's adjuvant alone both reduced the severity of the pneumonia caused by injections of bacteria into the apical lobe bronchi of rats. Neither protocol influenced the incidence of pneumococcal bacteremia. Illness sufficiently severe to require sacrifice was delayed from 2.8 days in nonimmunized animals to 5.7 days in those immunized with Freund's adjuvant and pneumolysin (P < 0.05) and 4.5 days in those stimulated with Freund's adjuvant alone (P, not significant).

Adjuvants, Immunologic↗
PubMed1992

Identification of an African swine fever virus gene with similarity to a myeloid differentiation primary response gene and a neurovirulence-associated gene of herpes simplex virus.

Here we describe an open reading frame (LMW23-NL) in the African swine fever virus genome that possesses striking similarity to a murine myeloid differentiation primary response gene (MyD116) and the neurovirulence-associated gene (ICP34.5) of herpes simplex virus. In all three proteins, a centrally located acidic region precedes a highly conserved, hydrophilic 56-amino-acid domain located at the carboxy terminus. LMW23-NL predicts a highly basic protein of 184 amino acids with an estimated molecular mass of 21.3 kDa. The similarity of LMW23-NL to genes involved in myeloid cell differentiation and viral host range suggests a role for it in African swine fever virus host range.

African Swine Fever Virus↗
PubMed1992

Effect of Pseudomonas aeruginosa rhamnolipids on mucociliary transport and ciliary beating.

Pseudomonas aeruginosa rhamnolipid causes ciliostasis and cell membrane damage to rabbit tissue, is a secretagogue in cats, and inhibits epithelial ion transport in sheep tissue. It could therefore perturb mucociliary clearance. We have investigated the effect of rhamnolipid on mucociliary transport in the anesthetized guinea pig and guinea pig and human respiratory epithelium in vitro. Application of rhamnolipid to the guinea pig tracheal mucosa reduced tracheal mucus velocity (TMV) in vivo in a dose-dependent manner: a 10-microgram bolus caused cessation of TMV without recovery; a 5-micrograms bolus reduced TMV over a period of 2 h by 22.6% (P = 0.037); a 2.5-microgram bolus caused no overall changes in TMV. The ultrastructure of guinea pig tracheal epithelium exposed to 10 micrograms of rhamnolipid in vivo was normal. Application of 1,000 micrograms/ml rhamnolipid had no effect on the ciliary beat frequency (CBF) of guinea pig tracheal rings in vitro after 30 min, but 250 micrograms/ml stopped ciliary beating after 3 h. Treatment with 100 micrograms/ml rhamnolipid caused immediate slowing of the CBF (P less than 0.01) of human nasal brushings (n = 7), which was maintained for 4 h. Mono- and dirhamnolipid had equivalent effects. The CBF of human nasal turbinate organ culture was also slowed by 100 micrograms/ml rhamnolipid, but only after 4 h (CBF test, 9.87 +/- 0.41 Hz; control, 11.48 +/- 0.27 Hz; P less than 0.05, n = 6), and there was subsequent recovery by 14 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Diagnosing infection in hip replacements. The use of fine-needle aspiration and radiometric culture.

In 78 consecutive patients, we performed fine-needle aspiration of the hip before revision surgery. At the revision operation biopsies were taken from the capsule and joint tissues. The aspirate and the homogenised soft-tissue specimens were cultured using a radiometric technique. Fifteen hips proved to be infected and 63 sterile on culture of the tissues taken during revision surgery; 94% of the aspiration results were correct. The sensitivity of the technique was 87% and the specificity 95%. Fine-needle aspiration combined with a radiometric culture technique is a simple and reliable method of diagnosing infection of hip prostheses.

Bacteria↗
PubMed1992

I think of Ronald Reagan: future selves in the present.

A nonlinear perspective on time (where the future exists in and affects the present) has been described by several theorists but there is little research on the extent, quality or origins of the personal future perspective. The present study examined the existence and origin of the future in the present by asking adults aged nineteen to eighty-three to: 1) project themselves into the oldest age imaginable, 2) describe their hopes and fears for that age, and 3) name role models for those hopes and fears. Data analysis revealed that length of future perspective, number of hopes and number of role models for the distant future declined with age. In addition, types of fears for the future varied with age, with older adults stressing dependency issues while younger adults reported concerns about personality and mental health. Despite age differences, most participants could name role models for both their hopes and fears for aging, but specific models were identified more often for hopes than for fears. Personalized hopes and fears for the distant future as motivators for the present are discussed.

Activities of Daily Living↗
PubMed1992

Propranolol retards revascularisation and impedes early myogenesis in regenerating skeletal muscle transplants: an autoradiographic and morphometric study in mice.

The beta-antagonist (blocker) propranolol was tested for its effects on satellite cell proliferation and the revascularisation and regeneration of transplanted skeletal muscles. Utilising autoradiographic techniques it was found that there was no difference in the actual timing of onset of satellite cell activation between propranolol-treated and control mice. However, the numbers of proliferating myogenic cells were substantially reduced in the propranolol-treated mice until revascularisation of these transplants began, about 24 h later than in the controls; myogenesis was therefore retarded by propranolol. When transplants from propranolol-treated and control mice which had been allowed to regenerate for 14 d were analysed morphometrically it was found that there was no significant difference in the size of the transplants, although propranolol induced the formation of substantial lipid deposition in the central transplant region; this was evidence of inhibited revascularisation in the early stages (up to 4 d) after transplantation.

Animals↗
PubMed1992

The effects of clenbuterol on satellite cell activation and the regeneration of skeletal muscle: an autoradiographic and morphometric study of whole muscle transplants in mice.

The beta-2 agonist clenbuterol was tested for its effect on the proliferation of satellite cells in transplanted skeletal muscles. Using autoradiographic techniques it was found that satellite cells in clenbuterol treated transplants began proliferating earlier than in control animals. The effect of clenbuterol on the growth of regenerating muscle fibres was also examined using morphometric techniques, which manifested itself as hypertrophy of the fibres when compared with the controls.

Animals↗
PubMed1992

The effects of pre- and posttransplantation exercise on satellite cell activation and the regeneration of skeletal muscle transplants: a morphometric and autoradiographic study in mice.

The effects of pre- and posttransplantation exercise on satellite cell activation, and the eventual regeneration of skeletal muscle transplants, were studied histologically, morphometrically and autoradiographically. It was found that satellite cells in these transplants were synthesising DNA 30 h after transplantation, and the transplants appeared to be revascularising at 60 h after surgery. Respectively, this was 18 and 12 h earlier than found in previous studies on nonexercising muscle using the same techniques. The morphometric analysis showed hypertrophy of the muscle fibres of the exercised transplants when compared with controls, and also an increase in the capillarity of the exercised transplants.

Animals↗
PubMed1991

Demonstration of insulin and glucagon mRNA in routinely fixed and processed pancreatic tissue by in-situ hybridization.

Human insulin and glucagon mRNA were identified in routinely processed pancreatic tissue by non-radioactive in-situ hybridization using digoxigenin-labelled oligonucleotide probes. Cocktails of synthetic oligonucleotides complementary to human insulin and glucagon mRNA were labelled with digoxigenin using terminal deoxynucleotidyl transferase (Tdt). Specific hybrids were detected with alkaline phosphatase-labelled anti-digoxigenin antibody and visualized by BCIP-nitroblue tetrazolium indicator substrate. The results showed highly sensitive and specific staining of islet cells on a range of routinely formalin-fixed and paraffin-embedded tissues. Post-mortem pancreatic tissue from adults and stillborn neonates yielded acceptable signals as long as tissue morphology was well preserved. Preliminary investigations using pancreatic endocrine cell tumours gave clear easily interpretable signals which were comparable to conventional immunostaining. The application of this technique promises to be of value in the investigation of pancreatic disease.

Adult↗
PubMed1991

A very large PC LAN as the basis for a hospital information system.

Brigham and Women's Hospital is converting its financial, administrative and clinical information systems from a mini-computer environment to a platform based on MUMPS and a network of several thousand personal computers. This article describes the project rationale and status and provides an overview of the architecture of the new system. The initial results of the project indicate that the personal computer network can provide large amounts of processor power and storage at costs per unit of power and storage that are several times less expensive than the minicomputer environment. The performance of the converted Accounts Payable system indicates that the architecture can deliver acceptable performance.

Hospital Information Systems↗
PubMed1991

Milk-induced malabsorption in malnourished African patients.

Fifty malnourished rural African patients were randomly assigned to whole milk (50 g lactose/L), acidified milk (24 g lactose/L), or a commercial lactose-free diet (LFD) as a constant nasogastric infusion for 3 d, starting at 2 L/d and increasing to 3 L/d if tolerated. During the first 2 d mild symptoms of intolerance developed in 63% of patients on whole milk, 37% on acidified milk, and 54% on LFD whereas severe intolerance, necessitating withdrawal, was encountered in 22% receiving whole milk and none receiving LFD. Stool weights and fat excretion on day 3 were greater (P less than 0.02) in the remaining milk-fed patients whereas nitrogen balance remained strongly positive in all three groups. Eighty-seven percent of patients were methane producers, and high excretion rates were associated with better milk tolerance. The results suggest that although undiluted cow milk will not form a suitable tube feed for malnourished African patients, products such as acidified milk may prove cost effective.

Adult↗
PubMed1991

Development of tolerance to and physical dependence on ethanol: daily versus repeated cycles treatment with ethanol.

We examined the effect of various treatment schedules with ethanol on the development of tolerance and the severity of withdrawal in rats. Tolerance to ethanol was examined after a challenge dose of ethanol using rectal temperature, dowel performance, and tail flick response; open field activity and the startle response were determined during withdrawal. Animals treated daily with ethanol developed greater tolerance, and also lost it faster, compared with animals subjected to repeated cycles of 3 days of ethanol treatment followed by 3 drug-free days. Also, the severity of withdrawal was greater in animals treated daily with ethanol. In the second study, we examined the development of tolerance and withdrawal severity of animals subjected to three different schedules of daily ethanol administration. Overall, the animals receiving continuous infusion of ethanol showed the most severe withdrawal and had, except for dowel performance, the fastest loss of tolerance to ethanol.

Alcohol Drinking↗