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Biomedical subjects

W H Marshall

Publications and source records attributed to W H Marshall.

At least 19 recordsLinked to original sources
PubMed1992

A low cost microprocessor-controlled electrofusion and electroporation system.

An important recent development in the field of biotechnology has been the use of high electric fields to render cell membranes temporarily permeable (electroporation). Cells in this state are receptive to gene transfer or can be induced to fuse with each other (electrofusion) to form hybrid cells containing the combined characteristics of the parent cells. A major reason for fusing cells is to form hybridoma cells which secrete monoclonal antibodies. A problem for research workers has been the high price of some of the electrofusion equipment. This problem has been addressed by designing a device that is inexpensive (less than $800 Canadian) and can be assembled by an electronics technician. The system uses a Radio Shack CoCo III microcomputer which is programmed in BASIC and controls the electroporation voltage pulse amplitude (25-500 V) and duration (2-275 microseconds) to an electrofusion chamber; this yields electric field strengths of 0.25-5 kV cm-1 for a 0.1 cm electrode spacing. The system is capable of delivering pulse currents up to 3 A. This paper provides technical details on how to construct an instrument that has greater flexibility at less cost than comparable commercially available instruments.

Biotechnology↗
PubMed1992

Increased limb salvage with intraoperative and postoperative ankle level urokinase infusion in acute lower extremity ischemia.

Over a 30-month period (May 1988 to November 1990) 143 acutely ischemic lower extremities (126 patients) were treated with an aggressive surgical approach that included ankle level tibial-peroneal artery thromboembolectomy. Twelve lower extremities in 10 patients that remained ischemic were further treated with adjuvant ankle level urokinase infusion. Sixteen ankle level arteries in 12 extremities were infused with an intraoperative bolus (1 to 2) of urokinase (50,000 to 100,000 units). Continuous postoperative urokinase (25,000 to 50,000 units per catheter per hour x 1 to 5 days) was infused through ankle level arteriotomies in 10 extremities (14 arteries) that did not improve with the initial intraoperative bolus. Concomitant bypass grafting was necessary in four extremities. With adequate inflow established, adjuvant ankle level urokinase salvaged all 12 extremities. The mean increase in ankle/brachial pressure index was 0.84. During continuous postoperative urokinase infusion, lower extremity bleeding requiring blood transfusion occurred in four patients (50%). No deaths occurred in the operative period. Although rhabdomyolysis occurred in 90% of patients, no patients had renal insufficiency. The addition of ankle level urokinase delivery increased the potential limb salvage from 90% of the entire 143 extremities treated during this period to an actual limb salvage of 98%. A mean follow up of 13 months (6 to 36 months) identified one late amputation. Despite the demanding postoperative management required in these patients and the frequent need for early reoperation, the limb salvage obtained justifies this aggressive adjuvant technique in the management of the acutely ischemic lower extremity.

Aged↗
PubMed1991

Transfection of HLA genes using genomic DNA.

Mouse L cells expressing HLA genes are potentially useful for producing and analyzing monoclonal antibodies (mAb) to HLA molecules. This paper describes the preparation of transfectants using uncloned human DNA and three methods to isolate the HLA-expressing transfectants. Transfectant libraries were made by cotransfecting mouse thymidine kinase (tk)-deficient L cells with a calcium phosphate precipitate containing genomic DNA and tk plasmid DNA. Transfectants expressing HLA genes were isolated using these methods: immunomagnetism, replicate-plating combined with cellular enzyme-linked immunoassay, and sorting using a fluorescence-activated cell sorter. Two HLA-A2 transfectant were isolated using immunomagnetism, two HLA-A24 transfectants by replicate plating, and one HLA-Bw60 transfectant by FACS. However, no transfectants were isolated that stably expressed class II genes. The class I transfectants have been useful in characterizing several locally prepared mAbs which bind to monomorphic determinants on class I HLA molecules. Two of the transfectant lines, one expressing HLA-A2 (8001) and the other HLA-A24 (8008), have been included in the collection of lines distributed for use in the Eleventh International Histocompatibility Workshop.

Antibodies, Monoclonal↗
PubMed1991

Carotid endarterectomy in a community hospital surgical practice.

Three hundred twenty-four carotid endarterectomies (CEAs) were performed on 303 patients over 5 years. Sixty per cent of the patients were symptomatic with completed stroke (36.4%), amaurosis fugax (35.4%) or transient ischemic attack (TIA) (50.5%). Some patients had multiple symptoms. Perioperative stroke occurred in four patients (1.2%) and 30-day mortality in five (1.5%). The combined stroke-mortality rate was 2.8 per cent. Other postoperative complications included TIA (1.9%), cranial nerve injury (3.1%), wound hematoma (6.5%), and hypertensive reperfusion syndrome (9.6%). Ten early reoperations were performed for wound hematoma (7) or technical problems (3). Follow-up of 284 CEAs (88%) at a means of 31 months revealed 33 late deaths, with two due to stroke. Late strokes occurred in 11 patients (3.9%). Five late strokes were ipsilateral (1.8%) and six were contralateral (2.1%) to the operated carotid artery. Ninety-seven carotid arteries were evaluated by duplex ultrasound scanning at a mean postoperative interval of 27.2 months. Ninety-two per cent had 0-30 per cent restenosis, 5 per cent had 40 per cent to 60 per cent restenosis and 3 per cent had 70 per cent or greater restenosis. The authors conclude that CEA can be performed with acceptable morbidity and mortality rates and that it is a durable operation that reduces the risk of late stroke.

Adult↗
PubMed1979

A search for association between IgD concentrations and immunoglobulin allotypes in 936 sera from a genetic isolate in Newfoundland.

Immunoglobulin allotype (Gm) data has been analysed agaonst immunoglobulin D (IgD) concentrations in a population study in Newfoundland. There was no significant difference between the distribution of IgD concentrations in people homozygous for the alleles G1m(f) and G3m(b) when compared with people homozygous for the alleles G1m(a) and G3m(g). These findings, involving 573 homozygous individuals as opposed to ninety-eight in an earlier study on a New York population, do not confirm the earlier findings. Thus a genetic influence on IgD concentration by Gm genes or genes closely linked to them is not universally demonstrable by typing for these four markers and by using the Mancini technique for mearusing IgD concentration.

Gene Frequency↗
PubMed1979

A study of human leukocyte D locus related antigens in Graves' disease.

An association between Graves' disease and the human leukocyte antigen (HLA) system has previously been reported. The disease was more strongly associated with the HLA D locus antigen Dw3 than with HLA B8. Products of the HLA D locus are determined by the interaction of test cells with standard typing lymphocytes, a technically difficult procedure. Recently, it has been possible to type serologically for D locus related (DRw) specificities on peripheral bone marrow-derived (B) lymphocytes. Blood B lymphocytes from 50 unrelated controls and 41 patients with Graves' disease were typed for seven HLA DRw specificities. 28 patients with Graves' disease (68%) were positive for DRw3, in contrast to 14 controls (28%); whereas only 21 patients (50%) were HLA B8 positive, compared with 13 (26%) controls. Thus, positivity for DRw3 afforded a relative risk for Graves' disease of 5.5, whereas that for HLA B8 amounted to 3.0. Additionally, a family with multiple cases of Graves' disease in which the disease was previously shown to be inherited with the haplotype, was linked to DRw2, which suggests that the susceptibility to the disease was inherited in association with that antigen. Two HLA B/glyoxalase recombination events were observed in this family; in both instances HLA DRw followed HLA B. This study thus demonstrates that the disease susceptibility gene for Graves' disease is in strong linkage disequilibrium with DRw3; however, it may be associated with other DRw specificities and inherited within family units in association with them.

Alleles↗
PubMed1979

Cerebral infarction and migraine: clinical and radiologic correlations.

Cerebral infarction was documented by arteriography and serial computed cranial tomography (CT) in four young adults (ages 16 to 32 years) with migraine. In one case, posterior cerebral artery occlusion produced a deep parietotemporal infarct. The other three cases all had frontotemporal infarcts (one hemorrhagic) in the territory of the middle cerebral artery, without major arterial occlusion. Two infarcts produced lasting neurologic deficits; one was associated with mild, transitory symptoms, and one was asymtomatic. Laboratory investigations in two cases revealed no hematologic or cardiovascular predisposition to cerebrovascular disease. Cerebral infarction, as revealed by CT, may be more prevalent in "complicated" migraine than is generally appreciated. Such lesions may or may not develop in chronologic and anatomic relationship to the headache, and may involve either large or small arteries. The prognosis for functional recovery, based on this limited sample, seems favorable.

Adolescent↗
PubMed1979

Rupture of intracranial aneurysms during cerebral angiography: report of ten cases and review of the literautre.

Ten new cases of intracranial aneurysms that ruptured during cerebral angiography, obtained from four local hospitals and the practices of eight angiographers, are detailed. A review of the literature reveals 28 other well-documented cases. An analysis of this clinical material shows that internal carotid injections are not necessarily more dangerous than common carotid injections. Although critically ill patients are at higher risk and must be treated with caution, there is not enough evidence to warrant a delay in angiography to avoid rupture. The recent trend toward early angiography in cases of subarachnoid hemorrhage is reflected in the statistical analysis. A plea for meticulous angiographic technique is advanced.

Adult↗
PubMed1978

The HLA B w4/w6 diallelic system in Graves' disease.

We studied the diallelic system HLA--Bw4/w6 in patients with Graves' disease and control subjects. Twenty-one out of the 22 patients with Graves' disease were found to be HLA--Bw6 positive and 16 of these were homozygous, contrasted with 28 and 9 out of 34 controls, respectively. HLA--Bw6 positivity results in a relative risk for Graves' disease of 3.27; homozygosity for that allele further increases the risk to 7.4. It is possible that the increased risk attached to HLA--Bw6 is secondary to the increase in HLA--B8 previously described in Graves' disease.

Alleles↗
PubMed1978

Tuberculosis associated with HLA--B8, BfS in a Newfoundland community study.

In three adjacent Newfoundland communities comprising some 1500 people, 589 people have been HLA typed. Forty-six of the typed people gave a history of previous clinical tuberculosis which required treatment. Fifty-six percent of the TB patients carried HLA B8 compared with 20% of the remainder of the population. This is a highly significant difference (P less than 0.01). In each community the frequency of B8 as an epidemiological marker correlated with the incidence of tuberculosis. B8 is associated with TB in ths study with a relative risk of 5.2 which compares with combined relative risks in the literature for coeliac disease and Addison's disease of 9.5 and 6.4, respectively, and which is greater than the risks for all the other B8-related diseases. The factor B allele, Bf S, was found on all the B8 haplotypes, but the overall Bf gene frequencies in tuberculosis patients did not deviate from expected values.

Cytotoxicity Tests, Immunologic↗
PubMed1978

The operation of immunological networks in Graves' disease.

Association between Graves' disease and HLA--B8 has been previously documented, as have been associations between 1 gG heavy chain allotype markers (Gm). We found a significant increase in the phenotype fnb/fb (ie. positivity for fb) in patients with Graves' disease compared to controls, raising the possibility of allotypic restriction of thyroid stimulating antibodies thought to be causally related to the disease. The influence of fb on the susceptibility to Graves' disease was found to be independent of HLA--B8 status suggesting that the immunological network operated by the Histocompatibility-linked genes is independent of that centered around IgG allotypes. It is postulated that, whereas the former genes determine the level of helper T lymphocyte function in the production of thyroid stimulating antibodies in Graves' disease, a person who also happens to carry the Gm marker fb would be assured of the production of IgG antibodies with thyroid stimulatory activity.

Adult↗
PubMed1978

The association of HLA with juvenile diabetes mellitus in Newfoundland.

In view of the reported variation in the association between HLA antigens and Juvenile Diabetes Mellitus (J.D.M.) among different Caucasian populations, we have undertaken a study of these antigens among 44 Caucasian Newfoundlanders and 135 matched controls. We have also studied the allotypic markers for Immunoglobulin G (Gm) and variants of C3 among 36 of these patients. We found that both HLA--B8 and B15 were increased among the patient group, resulting in a relative risk of 3.9 and 4.4 respectively. While these values are the highest to be described for J.D.M. among Caucasians, and fell outside the 95% confidence intervals for the combined relative risk calculated from published series, it is still possible that they can be accounted for by sampling. The combination of the two antigens increased the relative risk for J.D.M. in an additive fashion. Additionally, we also found that the combination of HLA B8 and B18, but not B15 and B18, also appear to act in an additive manner. The incidence of Gm allotypes and variants of C3 were not different in the J.D.M. group from those observed among controls.

Adolescent↗