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Biomedical subjects

J Ferguson

Publications and source records attributed to J Ferguson.

At least 307 records · Page 17Linked to original sources
PubMed1981

The role of M.D.-Ph.D. training in increasing the supply of physician-scientists.

Since 1968 the number of postdoctoral research fellows with M.D.s or other professional degrees has fallen from about 4100 to 1730 in training each year. By 1980, the number of M.D. postdoctoral fellows entering and completing research training was about 850 per year. During the past 12 years, the number of M.D.-Ph.D. trainees has risen to about 650 in the federal Medical Scientist Training Program (MSTP) and about 500 in nonfederal programs. The attrition rate in non-federal M.D.-Ph.D. programs has been shown to be 44 per cent, and that from the MSTP, 9 per cent. When the length of the training program, the attrition rate, and other factors are considered, present trainees will account for about 150 M.D.-Ph.D. graduates annually in the immediate future. Current training programs can meet only about half the estimated national need for physician researchers. The federal M.D.-Ph.D. program should be expanded to ensure that the country's future research and teaching needs will be met.

Education, Graduate↗
PubMed1981

Construction and characterization of three yeast-Escherichia coli shuttle vectors designed for rapid subcloning of yeast genes on small DNA fragments.

We have constructed three new subcloning plasmid vectors, pRC1, pRC2, and pRC3, derived from pKC7, which allow the rapid, single-step subcloning of yeast genes. Subcloning with these vectors utilizes a partial digestion with Sau3A to generate a quasi-random set of DNA fragments from the original plasmid. All three vectors contain a kanamycin resistance gene. Therefore, if the original cloned yeast DNA fragment is present in a vector that does not specify kanamycin resistance, the subclone pool can be propagated in Escherichia coli in the presence of kanamycin to select against parent plasmids that escaped restriction by Sau3A. Selection by complementation in yeast yields a collection of plasmids with smaller yeast DNA inserts containing the gene of interest. In the vectors pRC2 and pRC3, constructed from pRC1, the unique BamHI site is located within an intact tetracycline resistance gene, thus making it possible to screen bacterial transformants for those containing recombinant plasmid molecules. Vectors pRC2 and pRC3 also contain the yeast 2 micrometers DNA replication origin, and thus are more stable than plasmids carrying only the TRP1-associated replicator (ars1).

Cloning, Molecular↗
PubMed1981

Physostigmine and arecoline: effects of intravenous infusions in Alzheimer presenile dementia.

Physostigmine (0.25 mg-1 mg), arecoline (2 and 4 mg) and saline were administered intravenously over 30 minutes in a randomized double blind design to 11 patients with a clinical diagnosis of Alzheimer presenile dementia. Significant improvement was seen on a picture recognition test with physostigmine 0.375 mg and arecholine 4 mg. A trend towards improvement was also seen with physostigmine 0.25 mg and 0.75 mg, and arecholine 2 mg. For the majority of the patients improvement was only slight but in two patients it was clear cut and consistent.

Alzheimer Disease↗
PubMed1979

Exacerbation of senile macular degeneration following cataract extraction.

Six eyes in four patients had hemorrhagic detachment of the retinal pigment epithelium following cataract extraction. All eyes had evidence of nonexudative senile macular degeneration preoperatively as manifested by drusen or alterations in the retinal pigment epithelium, or both. Postoperatively, all eyes had evidence of a subretinal neovascular membrane manifested by the presence of subretinal hemorrhage or by evidence on fluorescein anglography. We believe cataract extraction may cause changes in the choroidal hemodynamics that allow pre-existing new blood vessels to leak or bleed, or induces the formation of choroidal neovascularization in a predisposed eye.

Aged↗
PubMed1978

Dietitians as behavior--change agents.

The traditional relationship between the client and the dietitian or nutritionist has been that of student and teacher. In the past, a patient has received excellent dietary counseling and advice from the dietitian, but has often ignored what he or she has taught. Until recently, the referring physician could only blame the patient, the dietitian, or both for this failure. Dietitians needed some new tools. The behavioral sciences have taken a new look at the problems of obesity, including a new assumption, viz.at some time, the obese have learned to eat in a way that results in excess caloric intake. Treatment now includes not only nutritional and caloric instruction, but also an attempt to change eating habits and behaviors. With these new tools, the dietitian-teacher becomes a dietitian-behavior-change agent; in addition to food content, the context of food becomes important in dietary counseling. Although dietitians are not usually trained in behavioral counseling, the weight loss in groups led by dietitans, after only minimal instruction, is comparable to that reported for groups led by psychiatry residents.

Behavior Therapy↗
PubMed1977

Isolation of viable human pancreatic islets.

This article reports a method for the isolation of viable pancreatic islets from the human pancreas. Isolated islets were obtained from human pancreata of cadavers, patients undergoing surgical operations, and fetuses, using a freehand microdissection procedure. Viability was assessed by light microscopy of sections stained with aldehyde fuchsin and by measuring the insulin output of islets in response to a glucose stimulus in vitro using a perifusion system. Ten pieces of cadaver pancreas were studied. Islets were isolated from 6 specimens and in 5 of these were shown to respond to a glucose stimulus in vitro. Histologically the islets showed minimal damage with slight degranulation of the beta cells. Five pieces of pancreas removed at operation were studied as well. Islets were isolated in all cases, but only 2 showed a response to a glucose stimulus. Pancreata from a 26-week and 34-week human fetus were also studied. It was not possible to microdissect islets from either case, but small pieces of pancreas from the 26-week fetus were shown to respond to a glucose stimulus by producing a significant increase in insulin output.

Cadaver↗
PubMed1977

A method to facilitate the isolation and handling of stratum corneum.

A specially designed frame is being used in this laboratory to facilitate the isolation and handling of human cadaveric stratum corneum of the upper back. Although it is in the early stages of use, the ease of isolation and subsequent handling of the stratum corneum has prompted the writing of this short report.

Skin↗
PubMed1977

A technique for evaluating the stability of figures in a figure-ground pattern.

A technique is described which uses a reversible word-figure for studying effects of experimental variables on the stability of figures. In a reversible word-figure black on white inter-letter spaces represent "nonsense" forms which are usually perceived first. In this study the latency of reversal to the white on black word-configuration is taken as an index of the stability of the perceptual construction involving the black nonsense forms. The results show that pre-exposure of the nonsense forms increases their stability. Either labelling the forms or attempting to memorize them increases stability somewhat more than merely rating them for "aesthetic appeal."

Discrimination, Psychological↗
PubMed1977

Extended survival of pancreatic islet allografts in the testis of guinea-pigs.

1. Pancreatic islets, isolated from the guinea-pig pancreas by microdissection and transplanted as allografts to the testis, may survive for 11 weeks, some 5 times the maximum survival of orthotopic skin grafts. 2. Intratesticular islet cell allografts appear not to provoke a systemic immunity such as might be detected by the behaviour of a subsequent orthotopic skin allograft from the same donor. 3. Intratesticular islet cell allografts succumb (in 'second set' fashion) to a pre-existing immunity generated by a prior orthotopic skin allograft. 4. Further experimental work is necessary to determine the relative importance of graft dosage, graft antigenicity, graft site and 'graft adaptation' in determining this extended survival.

Animals↗
PubMed1977

Further studies on the transplantation of isolated pancreatic islets.

It is concluded that the extended survival of allografts of isolated pancreatic islets in the testis and in the omentum is probably due to several factors. 1. An element of 'privilege' in both graft sites, of unknown nature. 2. The small amount of tissue transplanted. 3. Weaker antigenicity of ancreatic islet tissue as compared with that of skin.

Animals↗
PubMed1977

DDT and DDE in the blood and diet of eskimo children from Hooper Bay, Alaska.

An analysis of the levels of DDT and DDE in the blood of some Alaskan Eskimo children and in the fat of some local marine mammals taken for food suggests that the children's pesticide burdin is only modestly lower than that of other American children. Authors suggest that some other food source, perhaps packaged food, supplies a portion of the dietary chlorohydrocarbon pesticide.

Adipose Tissue↗
PubMed1977

Central nervous system involvement in mycosis fungoides: pre mortem diagnosis by light and electron microsocopic study of the spinal fluid.

Involvement of the brain, spinal cord, peripheral nerves, meninges, and cerebrospinal pathways in mycosis fungoides manifests itself, clinically, as an obscure neurologic disturbance, occurring in patients with cutaneous manifestations of that disorder. Neurologic expressions of this particular cutaneous lymphoma are infrequently reported, in spite of the fact that many patients dying in the course of mycosis fungoides have pathologically demonstrable central nervous system, peripheral nervous system, and meningeal involvement. We report here a patient who incurred devastating neurologic illness as one of the initial features of the course of systemic dissemination of mycosis fungoides. Death occurred nine years after the onset of cutaneous illness. In this instance, cerebrospinal fluid cytologic studies established the diagnosis of nervous system involvement. Mycosis fungoides cells shed into the cerebrospinal fluid were studied by special techniques of light and electron microscopy. Brain scan abnormalities were present, which were clinically correlative with foci of brain involvement. The initial response of patient's nervous system illness to therapy was gratifying but unsustained, and she went on to fatal brain and multiple organ involvement with disseminated mycosis fungoides. The techniques of spinal fluid cytologic diagnosis, confirmatory of the etiology of disease in this case, may have practical appications in the diagnosis of otherwise obscure neurologic disorders.

Adult↗
PubMed1976

Isolation and preservation of islets from the mouse, rat, guinea-pig and human pancreas.

Viable islets of Langerhans have been isolated from the mouse, rat, guinea-pig and human pancreas using a free hand microdissection procedure. Viablity has been assessed by light microscopy of sections stained with Gomori's aldehyde fuchsin and by measuring the insulin release from islets in vitro in response to a glucose stimulus. Ten pieces of human cadaver pancreas have been studied. Islets were isolated from 6 and in 5 cases were shown to respond to a glucose stimulus in vitro. Five pieces of human pancreas removed at operation have been studied. Islets were isolated in all cases but only 2 showed a response to a glucose stimulus. Isolated animal islets have been subjected to three preservation systems and their viability following storage noted. 1. Simple cold storage in Hank's balanced salt solution at 4 degrees C. At 15 hours 100% survival was noted. This dropped to 10% at 48 hours. There were no survivors at 72 hours. 2. Subzero storage. In group I (freezing rate 1 degree C/min) histological survival was 35% and functional survival 20%. In group II (freezing rate 5 degrees C/min with a 24-hour culture period after rewarming) histological survival was approximately 87% and functional survival 75%. 3. Organ culture. Islets from the guinea-pig, rat and mouse showed minimal morphological damage when cultured for 21 days in a simple organ culture system. At 28 days histological survival was approximately 30%. We were unable to correlate histological and functional survival in this group.

Adult↗