Search PubMed⌕ Search

Biomedical subjects

A R Smith

Publications and source records attributed to A R Smith.

At least 163 records · Page 9Linked to original sources
PubMed1982

Pion radiotherapy at LAMPF.

Clinical investigations of pi meson radiotherapy were conducted by the Cancer Research and Treatment Center of the University of New Mexico and the Los Alamos National Laboratory from 1974 until 1982. Two hundred and thirty patients have been treated for a variety of locally advanced primary and metastatic neoplasms. One hundred and ninety-six patients have been followed for a minimum of 18 months. Crude survival data range from 11% for unresectable pancreatic carcinoma to 82% for Stages C and D1 adenocarcinoma of the prostate. Acute tolerance of normal tissues is approximately 4500 pion rad in 36 fractions over 7 weeks. Severe chronic reactions have appeared with increasing frequency after doses in excess of 4000 pion rad.

Adenocarcinoma↗
PubMed1982

Effect of an intramammary polyethylene device in primiparous dairy cows.

A sterilized polyethylene intramammary device (IMD) was inserted through the papillary duct into a front and a rear mammary quarter of 12 primiparous dairy cows, which were mastitis-free. This study was conducted during lactation from month 1 postpartum to completion (generally month 9). After the device was inserted, milk somatic cell counts (SCC) increased. Milk scc in the quarters fitted with IMD from foremilk, primary, and stripping samples were 5.2, 2.6, and 5.9 X 10(5) cells/ml, respectively. Comparable counts for control quarters were 2.1, 1.4, and 3.6 X 10(5) cells/ml. The SCC in foremilk from the quarters fitted with the device were 2 to 3 times greater than the counts in foremilk from control quarters during month 2 and subsequent months of lactation. The SCC were significantly increased in primary and stripping samples from quarters fitted with IMD; however, the SCC of 2.6 X 10(5) cells/ml in primary milk would not affect market milk quality. Milk production for the lactation was decreased (0.6 kg/quarter/day) in the quarters fitted with IMD in comparison with control quarters throughout the lactation. There were no differences in percentages of milk fat or protein between deviced and control quarters. Conductivity values were increased in foremilk and stripping samples, but not in primary samples, for the quarters with IMD. Bovine serum albumin concentrations were also increased.

Animals↗
PubMed1981

Oxygen levels in claudicating fingers: a 3 year follow-up after replantation.

After successful replantation of amputated digits some patients develop signs and symptoms of claudication. In these replanted claudicating digits the pO2 levels are 20% lower than those found in "control" fingers or in successfully replanted digits which do not demonstrate claudication. These symptoms could be explained theoretically by postulating (i) partial arterial thrombosis and/or (ii) an impaired sympathetic nervous system. Observations on our small series of 10 patients suggest that the first explanation is improbable.

Fingers↗
PubMed1980

Monolayer destruction by leukocytes from patients with multiple sclerosis.

Separated lymphoid cells from patients suffering from multiple sclerosis (MS) were co-cultivated with various cell lines. Over 80% of such co-cultivations showed destruction of the tissue-culture monolayers, whereas less than 5% of "normal" blood co-cultivation behaved in the same manner. Because of the possible involvement of virus in the aetiology of MS, many positive co-cultivations were 1) examined electron-microscopically, but no virus particles were seen; and 2) tested for measles and herpes viruses using immunofluorescent techniques, but these also proved negative. Leukocytes from stroke patients showed monolayer destruction in about 50% of cases. Granulocyte contamination was high in the stroke blood samples. Reduction of granulocyte numbers to "normal" levels completely abrogated the effect in the stroke samples, but had no effect on the MS co-cultivations. Monolayer destruction by MS leukocytes also appeared not to be due to lymphotoxin.

Cell Line↗
PubMed1980

Tissue reaction & tumor response with negative pi mesons.

As a prelude to a randomized trial of negative pi meson (pion) radiotherapy, as compared to conventional radiation treatment, tolerance of several normal tissues was investigated. Fifty-three of 108 patients received at least 2700 peak pion rads at a usual dose rate between 100 and 125 rads daily. The major sites treated were head and neck, pancreas, prostate, rectum and brain. Acute normal tissue reactions, late effects, and tumor response are correlated with the two dose levels. Pancreatic tumors have not fared well. At this point, tumors that can be observed disappear more rapidly, and, for tumors that cannot be observed, symptoms disappear more rapidly and normal tissues exhibit less reaction than with conventional radiotherapy. It is believed that the dose level can be raised an additional 7 percent above the current 4100 rads, measured at the maximum within the treatment volume.

Elementary Particles↗
PubMed1979

Experience with pion radiotherapy.

Forty-one patients with a total of 86 tumors were treated with negative pimesons (pions) at the Los Alamos Meson Physics Facility (LAMPF) through December 31, 1977. An additional 30 tumors in the total patient population were treated with 100 kVp x-rays to assess comparative effects on skin nodules and 8 patients received additive photon or electron radiation to pion-treated portals. Of 52 evaluable tumors in 20 patients treated with pions only and followed for 3 to 22 months, 81% (42 tumors) completely regressed; 6% (3 tumors) partially regressed; and 13% (7 tumors) did not respond, although 5 of the 7 have shown no growth for 10 months. Of eight tumors in seven patients treated with a combination of pions and conventional radiation, three tumors showed complete response and five tumors showed partial response, though the resected specimens in two (one with complete and one with partial response) revealed no tumor microscopically. Reactions in normal tissues have been mild, with some patients exhibiting no normal tissue reaction, as compared with relatively marked tumor response.

Abdominal Neoplasms↗
PubMed1979

Mastitis history, California Mastitis Test, and somatic cell counts for identifying cows for treatment in a selective dry cow therapy program.

Mastitis history, California Mastitis Test scores, and filter-deoxyribonucleic acid cell counts from 232 cows were used to project the effectiveness of criteria which could be used to determine which cows to treat in a selective dry cow therapy program. Bacteriological analyses of quarter milk samples were used to identify infected cows. Effects of month, lactation parity, stage of lactation, and interaction of stage of lactation with lactation parity on somatic cell numbers in milk were determined. The various criteria singly or in combinations correctly identified from 50 to over 92% of the cows with one or more infected quarters at drying off. However, from 25 to 80% of the cows free of infection would have been treated as well. The most discriminating criteria were two monthly cell counts exceeding 500,000 cells per milliliter where 53% of the cows with infected quarters were identified correctly and only 25% of the uninfected cows would be treated, or the two monthly cell counts exceeding 500,000 cells per milliliter plus a California Mastitis Test score of +2 or +3 at drying off. Here 89% of the cows with infected quarters would be treated, and 56% of the uninfected cows would be treated.

Animals↗
PubMed1978

Alterations in plasma and CSF amino acids, amines and metabolites in hepatic coma.

The dog with an end-to-side portacaval shunt (PCS) has been extensively used as a model to investigate hepatic encephalopathy (HE) as it demonstrates a plasma amino acid pattern similar to patients with chronic liver disease. In adult mongrel dogs, the effect of PCS on plasma and CSF amino acids, octopamine (OCT), phenylethanolamine (PEA) and CSF 5-hydroxyindolacetic acid (5-HIAA), were studied. Moreover, the effect of correction of plasma amino acids by infusional techniques was investigated.Tyrosine, tryptophan and phenylalanine levels increased dramatically during the development of HE in plasma and CSF, while valine, leucine and isoleucine decreased in plasma only, but CSF levels remained stable. Plasma and CSF octopamine and phenylethanolamine and CSF 5-HIAA increased markedly as clinical features in the dogs' behavior, characteristic of hepatic encephalopathy occurred, including hypersalivation, ataxia, flapping tremor, somnolence and finally coma. Once in coma, the dogs were infused with an amino acid mixture (F080) calculated to normalize the plasma amino acid pattern. After one to eight hours, the dogs began to awake. Simultaneously, blood, and CSF aromatic amino acids returned to their control values, as did OCT, PEA and CSF 5-HIAA. If F080 infusion was stopped, biochemical alterations would appear within one week, again accompanied by clinical hepatic encephalopathy.The results indicate that the altered levels of aromatic and branched chain amino acids, octopamine and PEA in plasma and CSF correlate well with the development of HE and that correction of the plasma amino acid abnormalities improves encephalopathy simultaneously with correction of neurotransmitter derangements in CSF.

Amines↗